View Full Version : Just got my French Prisms
oman321
08-13-07, 11:24 AM
A while back there was a group buy hosted by Skhattane.
Unfortunately that group buy was not authorised by AVS and was therefore blocked and deleted from the site. Some of us though, did get in on the deal especially since it was posted for some time and seemed like a legit buy.
Anyways Skhattane did inform us that it would take a few months for the prisms made of BK7 glass and AR coated would take a few months to produce and then a couple of weeks to ship. It took a little while longer than expected and I was somewhat concerned wether I would ever get the prisms. I am happy to report that the prisms have made it here a'ok.
They were extremely well packed and shipped US priority mail. They actually came from PA. I only have opened one of the prisms which were carefully wrapped and it is in perfect order. I carefully held it up to look thru and see how the clarity appears and I can say that it is amazingly clear. Now I just need to work on an enclosure for them but it will probably be some time before I get to this as I am still working on my room. I temporarily set up my projector though for my son's b-day and if I can safely place them in front of the projector to see how they work I'll probably do that.
If anyone else is waiting for theirs they are on their way.
Thanks Skhattane maybe next time you can work with AVS to make it a smoother event.
1Sharpdog
08-14-07, 12:58 AM
Great to hear. I am waiting here in Canada with fingers crossed. Was shipping prepaid, or how much did it cost?
Luke
jplmain
08-14-07, 04:49 AM
What a cur incidences, I was just thinking to my self (befor I looked into avs) about maybe how I could fallen for such a scamed and, then I tuned into avs and the first thread I looked at was yours. That makes me feel better.
Mine should comming soon to Hawaii. I should now be thinking about my containment box too. Please feel free to share ideas.
I have metel milling machines. I can shape metal to any design. If someone could come up with a good drawings I could make one for the contribetor and me.
But most of all Thanks for the INFO.
T_MINTON
08-14-07, 06:09 AM
cool I am in your group so maybe soon for me I hope
oman321
08-14-07, 08:46 AM
Shipping in the US was 5 bucks. The place where they were ordered and shipped from ships anything to the US for 5 bucks. Not sure about Canada or HI but it should have been part of the payment.
I grabbed copies of pics from the original thread or from the french site (not sure which) of a couple of enclosures.
oman321
08-14-07, 08:49 AM
and
This enclosure is made of pexiglass it appears. The last pic is a diagram for the cuts used. The prisms are smaller than you might think so you wanna wait till you get them before committing to anything.
oman321
08-14-07, 08:51 AM
Then there's a simple solution like:
Sorry no photo account.
oman321
08-14-07, 02:39 PM
I wanted to add these pics because they illustrates how to a create case which allows for a passthrough mode with dimensions. Again I don't take credit for any of these they are pics from the French site. Thanks goes to them they've done a lot of hard work.
Yes they have done their home work, but I do have to question their prisms angles, especially the rear prism. Based on the diagrams, I believe that the image will not provide a true symmetrical stretch, as the front prisms essentially stretched the left side whist the rear prisms essentially stretches the right side.
Did anyone them actually build the unit with a pass through?
Mark
1Sharpdog
08-15-07, 12:44 AM
I am now worried about the size of these prisms. What are their dimensions? It looks like they are only 2.5" high. I don't think that they are large enough for my w9000. Does anyone now if they will work?
Luke
The largest prism face is 110mm x 70mm or about 4.5" x 2.75" at 20 degrees, so pretty small...
Mark
voicecoils
08-15-07, 08:07 AM
i'm still waiting for mine to show up in Sydney. i've been regularly checking updates on the french site w/babelfish and haven't worried that i'd been scammed. i plan to make a simple sliding enclosure such as skhattane posted. cant wait!
oman321
08-15-07, 08:52 AM
Yes they have done their home work, but I do have to question their prisms angles, especially the rear prism. Based on the diagrams, I believe that the image will not provide a true symmetrical stretch, as the front prisms essentially stretched the right left side whist the rear prisms essentially stretches the right side.
Did anyone them actually build the unit with a pass through?
Mark
I wondered about the prism angle when I saw the rear one more straight and the front one at more of an angle on some of the pics I saw, like one of the diagrams above. I did see a setup on the french site with a picture flashing back and forth of an enclosure switching from pass to strech. It had some sort of binding mechanism which only allowed for the prisms to turn so far, If I find it I'll link to it.
When I held up the prism to look through it did shift everything over so I am confident it will work.
oman321
08-15-07, 09:03 AM
I am now worried about the size of these prisms. What are their dimensions? It looks like they are only 2.5" high. I don't think that they are large enough for my w9000. Does anyone now if they will work?
Luke
The prisms are small compared to others. Most of us asked if the prisms would work with a particular projector because of this, and if Skhattane knew of someone that had previously used it he would tell us so. Since you have one of the newer 1080P projectors their might not have been someone who tried it out.
You can try the paper test to see how large an image is being projected on to a white sheet of paper 6-8" away from the projector. If it is about 4" you should be ok. Good luck.
oman321
08-15-07, 09:29 AM
plan to make a simple sliding enclosure such as skhattane posted.
I liked his enclosure as well, simple top and bottom with a bolt at each corner. I wondered if the sides being open though would cause a flury of reflections even though the prisms are coated. We shall see soon enough :D
I wondered about the prism angle when I saw the rear one more straight and the front one at more of an angle on some of the pics I saw, like one of the diagrams above. I did see a setup on the french site with a picture flashing back and forth of an enclosure switching from pass to strech. It had some sort of binding mechanism which only allowed for the prisms to turn so far, If I find it I'll link to it.
When I held up the prism to look through it did shift everything over so I am confident it will work.
My prisms are a bit less at around 14 degrees, but what I found when using two of the same angle (not any different from what you guys will doing) is that if you only moved the front prism, that only the left side will stretch. Yes you can get a full stretch by then turning the lens, but the stretch will not be symmetrical...
Mark
oman321
08-15-07, 10:32 AM
http://www.homecinema-fr.com/forum/viewtopic.php?t=29803723&postdays=0&postorder=asc&start=3030
This is the link to the French site with the rotating enclosure. I thought they used these prisms to make it, but it appears to be of the home brew variety. It's a little past half way down after the first enclosure.
Mark, the first pic in post #8 shows the prisms flat against each other, when shifted for stretch the opposite side becomes flat against the projector lens. Not sure of the properties of these prisms but it will be fun to see how they come together. I almost wish I had ordered a spare set for testing, now I have to be extremely careful.
T_MINTON
08-15-07, 08:03 PM
Got mine today!!!! In perfect condition. Thanks SAM, where-ever you are...
http://www.homecinema-fr.com/forum/viewtopic.php?t=29803723&postdays=0&postorder=asc&start=3030
This is the link to the French site with the rotating enclosure. I thought they used these prisms to make it, but it appears to be of the home brew variety. It's a little past half way down after the first enclosure.
Mark, the first pic in post #8 shows the prisms flat against each other, when shifted for stretch the opposite side becomes flat against the projector lens. Not sure of the properties of these prisms but it will be fun to see how they come together. I almost wish I had ordered a spare set for testing, now I have to be extremely careful.
A thicker prism (ie 20 degrees) won't need as much angle as a thinner prism, but I think that you will find that the angles still need to be the same off the centre axis for both prisms. This has been well documented on both this site as well diyaudio.
It would change if the prisms used different angles, or were made from different materials, but in this case, both are BK7 and both have a 20 degree angle...
Mark
oman321
08-15-07, 08:56 PM
That's good news T_MINTON,
Are you ready to go with your set up? If you are, post some pics of what you end up doing.
Got mine today!!!! In perfect condition. Thanks SAM, where-ever you are...
I also got mine. I have not unpacked them. I hope they are ok.
But the concern is if they would work. They seem awfully small and they are
not identical as the package looks like and as CAVX points out that
could be a problem.
Anyway will wait and see if $126 works or if it is down the drain already.
Most likely I will sell one pair or both the pairs and will post a message.
If the mods are irresponsible enough to delete this thread or this post then
check videogon or ebay.
They seem awfully small and they are
not identical as the package looks like and as CAVX points out that
could be a problem.
No, they have the same angles, but the prisms' shapes are specified as front and rear, where the larger prism is the front...
Mark
T_MINTON
08-16-07, 05:32 AM
I don't believe they are too small. It will be a while before I get set up...I may need some help from MARK about throw distance for these. I have an NEC HT 1000.Older , but stil a great picture. I am sure I need to move PJ closer to screen or I will be way too big. Plus I am gone next week to Gatlinburg and BRISTOL race.
I may need some help from MARK
I don't know how much help I'll be - I don't own a pair of these. You need to work off the smallest image size possible within the zoom range...
Mark
oman321
08-16-07, 10:16 AM
Curious Mark,
Does that mean start with the smallest image possible and go up from there? I understood for CIH that one would start with their preferred 16:9 image and then place the prism's in front to get 2:35.
I will most likely have to start/go with my smallest image size since i'm projecting from about 15-16' and have to account for speaker placement and masking which I will have recess to the sides or above.
So much to do, such little time.
Curious Mark,
Does that mean start with the smallest image possible and go up from there? I understood for CIH that one would start with their preferred 16:9 image and then place the prism's in front to get 2:35.
These prisms are small, so your TR is going to have to be quite high even though Sam did make a post in the now deleted thread that 1.4:1 would work, I seriously doubt that. I'm at 1.3:1 and the image in the front prism of my lens is just under the full width of 170mm, so no chance that 110mm is going to work on my system...
I will most likely have to start/go with my smallest image size since i'm projecting from about 15-16' and have to account for speaker placement and masking which I will have recess to the sides or above.
So much to do, such little time.
I suggest to start with the smallest image size, then move the projector back if you have the room and still want a bigger image. For so long, people have relied on the zoom on the projector for more light and larger image size. That is OK when there is no anamorphic lens involved, but now you have to fit that light inside a very small area and not clip (vignette) the beam...
Mark
oman321
08-16-07, 10:57 AM
Got it, I understand now.
Thanks for the tips. I'm getting eager, maybe this weekend I might try to start an enclosure. We'll see if time allows.
snowkirk
08-16-07, 12:54 PM
Oman and others,
Were you in the first batch or second batch? Mine was in the second batch and I got a message sometime in June from Skhattane that he would be sending them out end of July or so....
oman321
08-16-07, 01:06 PM
Second Batch,
I think first batch was quite some time ago. I got the same message about July but then there was a message on the French site that they had been delayed and were shipping in a week at the beginning of August. A third batch never took off. You should be getting yours soon.
well I unpacked the prisms tonight. It was very well wraped. Thanks.
They seem very well made.
I havent been abke to get the right placement. At least the
image coming through the prisms is very clear. My 16:9 image is very small.
Only 63'' wide as I changed the projector location from the previous location which gave me 77'' wide 16:9 image. The 2.35 image would then get too big.
So I moved the projector to another location.
I have Infocus IN72. I believe its throw ratio is 1.77 to 2.16. I am at full zoom so mine is 1.77 which I guess should be ok. The image on the second prism is not going out of the prism but like I said I havent got the right placement yet.
I need to check one of the posts in the other thread to get the right placement
of the prisms.
It looks promising so far
oman321
08-16-07, 11:03 PM
That's good news Mupi,
Have you tried to set them up like the first image in post 5? I would try that and then angle the rear prism as you go. Good luck.
yes I just tried it and I am able to get a nice rectangular image. I am
not playing an anamorphic DVD. I just tried ESPNHD. I just wanted to see
if I can get a nice rectangular 2.35 image. I had to tilt both the prisms
as they werent perfectly normal to the beam. That can be fixed as my
projector is probably tilted. Notthing is perfect yet.
There is some reflection. Mine is table mounted. There is reflection to the
left and back but not like the reflections from the mirror like Massillon Plaque
prisms. If I just keep my hand on the side and back the reflections are gone.
So putting a simple enclosure would get rid of the reflections.
Yes the angles of the 2 prims are the same. It is a good way of cutting the cost
by making the first prism smaller.
I thought the left and right edges were a bit blurry. It could also be the
overscan thing. Who cares about the edges.
I am going to ask my coworker to come to my place so that he can give his
opinion as he has more experience with HT. He can also take a picture.
I am sure he is reading this post :-)
I just wonder why the pro lenses cost $3000. Just due to monopoly.
I think with more and more people going the DIY route the
price of the pro lenses will drop soon.
The picture looks pretty good to me. I am sure it will look a lot better when
I play an anamorphic 2.35 DVD
With a $600 projector and $126 prism I cant ask for more.
My dream of watching a movie without bars seems to be finnaly coming true :-)
will post next week.
I just wonder why the pro lenses cost $3000. Just due to monopoly.
I think with more and more people going the DIY route the
price of the pro lenses will drop soon.
2 elements verses 5 (or more)...
Mark
jplmain
08-17-07, 05:43 AM
I was in the last batch and received mine today. For the priced payed for coated lens and 5 dollar shipping to boot I feel this was a good gamble.
I have my 7210 hanging upside down so it's going to be while to test mine (until I can get my box and sled ready).
I have a existing pornamorph 100u (vertical compression). I will build my box around my panamorph's existing sled and bracket. Hope to have pictures someday.
oman321
08-17-07, 09:04 AM
Good to hear Mupi, glad you were able to get a good image.
jplmain, $5.00 to HI I don't think you'll get that anywhere else.
Guys post them pics when you get them, I'll try to do the same. I'm gonna try to start a wooden enclosure and probably line the top and bottom with something that will grip the prisms. I intend to use some sort of sled or slide system.
2 elements verses 5 (or more)...
Mark
and what are those extra elements?
MDF or aluminum enclosures? nuts and bolts for adjustment? mounts?
Even if the quality of the prisms is better and there are more
layers of coating it doesnt justify a whopping $3000
They dont have to strive to make such perfect lenses.
How many people here have a projector that is $5000 or more
to justify buying a $3000 lens. Just like there are budget projectors
like IN72 that has an image quality of a $5000 projector, there
could be a budget lens too.
All we need is something like sams prisms that works and that has a
simple enclosure. If someone wants a sled then they have to pay more.
It shouldnt cost more than 50 bucks to make a MDF enclosure.
and what are those extra elements?
MDF or aluminum enclosures? nuts and bolts for adjustment? mounts?
No, they are extra bits of purpose made glass that correct for focus, CA etc. If anyone says they don't need them, it is because they have not yet seen the improvement they make...
Even if the quality of the prisms is better and there are more
layers of coating it doesnt justify a whopping $3000
Allot of the expense comes down to the finish of the surface. Yes the DIY prisms look smooth with no visible surface markings to the naked eye, but under a microscope, they full of pits and grooves. To get the best finish takes time, and time is money...
They dont have to strive to make such perfect lenses.
It depends on who is buying I suppose...
How many people here have a projector that is $5000 or more
to justify buying a $3000 lens. Just like there are budget projectors
like IN72 that has an image quality of a $5000 projector, there
could be a budget lens too.
All we need is something like sams prisms that works and that has a
simple enclosure. If someone wants a sled then they have to pay more.
It shouldnt cost more than 50 bucks to make a MDF enclosure.
That is subjective...
Mark
snowkirk
08-17-07, 01:26 PM
Well, the volume produced & sold is less which jacks up the per unit price. Photographic lenses have more elements, motors, better housing and I bet are better finished than these prisms but they sell a lot more of them....
I guess currently only ball players are buying those $3000 prisms :-)
oman321
08-18-07, 09:48 PM
I was able to make a simple enclosure with wood & cork board to hold the prism's in place. I aligned the prism's according to the template that I posted above and I was able to quickly test them out. Like Mupi it wasn't perfect but it will work it's just a matter of fine tuning it. The thing is that I have the projector on a shelf over my head and had to hold the enclosure in front of the lens and try to line it up. My image was rectangular though so I am quite pleased.
I snapped some pic's of the enclosure and matierials used, I'll post when I get some time.
There's a package waiting at the post office for me! Come on monday!!!!
snowkirk
08-18-07, 10:44 PM
I got mine delivered yday. They are very nicely packed. I hv to build an enclosure and bring down the projector to do some tests.
Oman - any pictures on how you built the enclosure would be useful, thx
Justletmein
08-19-07, 12:12 AM
Can I get the info on where to order these lenses please ? ... send me a pm if necessary ;)
jplmain
08-19-07, 04:30 AM
Can I get the info on where to order these lenses please ? ... send me a pm if necessary ;)
Sorry it was a one shot deal at (http://www.commandes-groupees.fr/viewtopic.php?p=4384). If you keep a eye on there site you might get chance to order when they get another batch lined up.
Someone on this thread (MUPI) ordered two pairs and might be selling one on ebay.
GetGray
08-19-07, 11:08 AM
I just wonder why the pro lenses cost $3000. Just due to monopoly. I think with more and more people going the DIY route the
price of the pro lenses will drop soon. The "pro" category is Isco and Schneider. List on the Isco (III) is $5999, List on a Cinedigitar is $4200. So I'm not sure which "pro" lens you are speaking of that is $3k.
But regarding the former, they cost more becasue they are photographic quality lenses, with multiple spherical and cylindrical lens elements. They have adjustable astigmatism correction, and precision (i.e. pro telescope quality) housings. Curves cost more, in many places ;)
Hi GetGray,
I think he (Mupi) is referring to the Panamorph UH380 (http://www.panamorph.com/ModelUH380.html) which I already explained (a few posts back) has 5 glass elements not 2...
Mark
oman321
08-19-07, 02:15 PM
Here go some pics of what I came up with.
oman321
08-19-07, 02:21 PM
I used the the image on post 5 to get the outside dimensions of the enclosure. If you print it out it you'll notice that it isn't to scale, so like I stated it worked for the outside dimensions. Then I reduced the image on a photocopier to 90% and that brought the image of the prisms closer to scale and that is what I use on the inside of the enclosure to help align the prisms.
oman321
08-19-07, 02:25 PM
Finally this is how it all came to gether. I'll be recessing the screws, priming and spray painting for a nice finish. Also I'll be making some sort of bracket and mounting it to a drawer slide. A quick test showed it worked nicely, but I need to either mount or bring my projector down to fine tune. :cool:
GetGray
08-19-07, 02:31 PM
I think he (Mupi) is referring to the Panamorph UH380 (http://www.panamorph.com/ModelUH380.html) which I already explained (a few posts back) has 5 glass elements not 2...Oops, sorry. Different conotatations for pro
snowkirk
08-19-07, 06:05 PM
Hi Oman,
Would be helpful to know the outside and inside dimensions and the thickness of the wood/cork board? Does it fit snug?
Well done Oman321, Sam would be proud ;)
Mark
oman321
08-20-07, 07:56 AM
Snowkirk,
The wood is 3/8 X 6 X 36 craft wood. If I did it again I would use 1/2" wood cause you might notice in my last pic one of my side panels split. It's ok I already replaced it, the 36" length left enough scrap.
I got all the material at Lowes. The cork board was a plastic backed disc for plant pots. It cut easily and worked like a charm. The prisms are nice and snug and I have held the enclosure in every direction to test out. The most important dimension is for the side panels, they measure 3 1/8" inches. Originally they measured 3&1/4 and they were sliding everywhere the 1/8th made all the difference. The cork board measures 3/16. The top and bottom pieces are 5&7/8" at the big end and 4&1/4" at the small.
Top and bottom were measured after the fact. The easy way was print out first image in post 5, then reduce to 90%. Cut out both images use bigger one for outside dimensions and smaller one for inside dimensions of cork board. Adhesive to glue cork boards, make sure you account for sides, you might have to trim a little extra from smaller image.
Sam, thanks.
I meant thanks Mark it was early when I posted, although thanks do still go to Sam.
So when are we going to see some screen shots?
Mark
oman321
08-20-07, 09:21 AM
The thing right now is that I have a temporary set up I did for my son's B-day at the beginning of the month, I am trying to figure things out with this. From my current projector location at about 16-17 ft. I am not so sure it's gonna work. It works but the image is taking over my entire 11ft.5in. wall.
I moved my projector to about 12 ft. last night but I haven't been able to test out yet. I'm not sure I want to do this because it would mean that I would have to change a few things i.e. my exhaust vent for the projector, outlet video wires. Also I have been testing regular 16:9 images because I haven't gotten a solution for anamorphic stretch yet. I'm thinking either HTPC or maybe the Key Digital scaler if it's still available when I'm ready.
I will be testing tonight hopefully from my new location and see what I can come up with. I can snap some pics but it wont look right unless I find that my DVD player might do the stretch. It's an upconverting panansonic and it has an extensive menu so im not sure.
For my sanity, and I think you've posted this before Mark. If I start with a 90in. width I would then multiply 90 X 1.33 to get a dimension 119.7?
Also I have been testing regular 16:9 images because I haven't gotten a solution for anamorphic stretch yet. I'm thinking either HTPC or maybe the Key Digital scaler if it's still available when I'm ready.
What source material are you running? Whilst HD might pose problem for some projectors, SD DVD (set to 16:9) should be able to be scaled using either "letterbox" or "4 x 3 zoom" in pretty much every projector except the Benq - w100 (which for reasons I can't work out does not have a letterbox mode)...
I will be testing tonight hopefully from my new location and see what I can come up with. I can snap some pics but it wont look right unless I find that my DVD player might do the stretch. It's an upconverting panansonic and it has an extensive menu so im not sure.
For the purpose of testing and initial set up, set it back to SD. The fact that you'll be using the full panel will be a huge PQ improvement anyway...
For my sanity, and I think you've posted this before Mark. If I start with a 90in. width I would then multiply 90 X 1.33 to get a dimension 119.7?
Your math looks good to me. Once the prisms are aligned correctly (and you need a 2.37:1 AR screen to do this), you will have a 1.33x stretch optical adaptor...
Mark
oman321
08-20-07, 10:09 AM
I was viewing 16:9 HD and SD. TNT was showing Forrest Gump and we have both versions of the station on Comcast Cable. With my cable box set to 480P on SD channels it creates a 16:9 image. instead of 4:3 when set to 480i.
I have an Epson HC 400 which offers some good aspect control but not vertical stretch. It was interesting because if offers a through mode for 16:9 HD & SD which reduces the image by about 10% overall but does not cutoff anything that I noticed. This might be a solution I could utilize perhaps if it comes down to it.
I quickly looked at the manual on line it states "Use Wide if you want to expand a 4:3 image to 16:9 so it fills the whole screen" so I suppose this is the mode I want on this projector.
I was viewing 16:9 HD and SD. TNT was showing Forrest Gump and we have both versions of the station on Comcast Cable. With my cable box set to 480P on SD channels it creates a 16:9 image. instead of 4:3 when set to 480i.
Sounds like it is looking to 16:9 for any HD input (not good, but nothing you can so - mine also does this), so set to 480i and see what happens...
I have an Epson HC 400 which offers some good aspect control but not vertical stretch. It was interesting because if offers a through mode for 16:9 HD & SD which reduces the image by about 10% overall but does not cutoff anything that I noticed. This might be a solution I could utilize perhaps if it comes down to it.
No projector (even the Cinewide from Runco) lists it as vertical stretch...
I quickly looked at the manual on line it states "Use Wide if you want to expand a 4:3 image to 16:9 so it fills the whole screen" so I suppose this is the mode I want on this projector.
So long as it clips the top and bottom off the image and does not stretch it...
Mark
oman321
08-20-07, 11:04 AM
Actually it states that it stretches left and right but leaves the center unchanged.
There is a note at the bottom of all the aspects that states " if you display a 4:3 image using the Zoom setting, the top and bottom will be cutoff" perhaps this setting then?
Here's a link to the page with the manual if you have the time and energy to take a peek it would be appreciated. It lists the aspects on page 27.
http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_UseBVCookie=yes&infoType=Doc&oid=75864&prodoid=63059180
I knew it wouldn't list it as V. stretch, I had previously asked and I was told the Epson's didn't offer it. Tough to get your head around all of this it took a while to understand CIH and as you can see I still have questions. Thanks again for the help.
Quick correction the cable box goes to 4:3 on SD when SD override is set to off. I will do that to see.
snowkirk
08-20-07, 04:25 PM
Oman,
Thanks for your response. Got the idea, trip to Lowes or HD this wkend.
There is a note at the bottom of all the aspects that states " if you display a 4:3 image using the Zoom setting, the top and bottom will be cutoff" perhaps this setting then?
Yes that is it, so the black bars are now what will be chopped off...
Quick correction the cable box goes to 4:3 on SD when SD override is set to off. I will do that to see.
The source must always be set to 16:9. The display will be set to a 4 x 3 mode. For optical stretched 16:9 (DTV), you simply use the native 4 x 3 mode or remove the lens and use 16:9 mode...
Mark
oman321
08-21-07, 07:46 AM
Ok, I got some pics. They're not great but its something, I'll give you a sample of one before and stretch and then 3 with lens in place.
This is my first attempt on screen pics so they're not fabolous. The last pic posted was the first one I took, I was setting the timer on the camera and then placing it down on an unlevel surface. So it's the camera at an angle not the image,for the rest of the pics I slightly held the camera up on that side.
After some testing with my setup I measured the image without and with the lens at my lowest zoom (the pics taken are with zoom set to about 1/3 or a little more). After calculating the measurements I realized that prisms are adding 1.55 to the image and need to be adjusted. Alas the Mrs. was hollaring for me to come up.
I noticed as I was reviewing my pics on my camera last night that the one of the plane with lens in place has a green push. I'm not sure if this is an anomoly of the camera or lens, I don't remember it like that on the screen so I will have to test that image again when I adjust the prisms'. The other stretched pics actually look better than the original shots and the white areas in those pics don't exhibit the same green tint. We shall see.
crocowhile
08-21-07, 03:03 PM
Hi guys,
I must be blind but I couldn't find where to order the French Prisms you are talking about. Is there another thread where they are described?
Thanks
Giorgio
oman321
08-21-07, 03:34 PM
crocowhile,
Read the first post, you'll see that their was an opportunity to buy these that was not authorised by AVS back March/April. That original thread has since been removed/deleted. This is more of a discussion of those that just recently recieved and will be using. Mupi might sell a second set he has, and some might later on sell theirs if not used.
You never know if the French forum mentioned earlier might offer another group, but you have to go there and use google to translate.
http://www.commandes-groupees.fr/viewtopic.php?p=4384
voicecoils
08-21-07, 06:45 PM
Ok, I got some pics. They're not great but its something, I'll give you a sample of one before and stretch and then 3 with lens in place.
Looks good, now I'm getting excited!
I noticed as I was reviewing my pics on my camera last night that the one of the plane with lens in place has a green push.
Could be the camera, I'd place more trust in what your eyes (or better yet a colorimeter) see on screen.
Good results so far and I look forward to a more refined version :)
Mark
oman321
08-21-07, 08:56 PM
Good news, color shift was something silly. Lose component cable :p
I also corrected for 1.33 vs. the 1.50-1.55 I was displaying.
oman321
08-21-07, 09:03 PM
Now another thing I wanted to try was vetical compression I didn't think it would work but here is something interesting...
I was able to make it happen, it was a little tricky but the first pic is vertical compression at lowest projector zoom the second was vertical compression at max zoom. The last two pics show how I placed the lenses. I didn't take exact measurements but you can manipulate to compress.
Now JPEG 010 doesn't look quite right (not stretched enough?) where 11 looks good. Interesting that you got the VC app to work...
You screen seems to show sag in the fabric. Are you using a frame to line this up?
Mark
voicecoils
08-22-07, 03:58 AM
mine arrived this afternoon.
small chip in the corner of the smaller prism, despite being very well packed :( may need to talk to sam about it if it affects the image.
this is a very high quality DIY product and I'm happy I made it into the group buy!
pics to follow soon...
voicecoils
08-22-07, 07:12 AM
Ok, some pic's after playing around.
Firstly, my Sanyo Z5 is currently mounted on top of a tall dresser to the left of my couch. It has extreme lens shift to the right and mild lens shift down. It is zoomed about midway. All in all, not ideal for putting prisms in front!
As a result I have some distortion but have a look at the pic's anyways:
test_setup: here you can see the Z5 on the dresser with the prisms mounted in front on a sheet of paper
anamorph_hcfr_crop_resize: This shows the distortion at the images edges but also shows that the stretch is preformed relatively uniformly across the image.
jarhead_HD_DVD-crop_resize: Shows a still of an HD-DVD being played with PDVD 7.3, yxy for the v-stretch, 2400Pro ati graphics card preforming hardware acceleration.
The last two images are of The Departed HD DVD, first without the lens (stretched by yxy) then with the lens for HE (horizontal expansion).
Yes, the projector must be positioned perfect first. Any off setting in the projector will only be magnified by the lens.
So you will be able to correct the pincushion, and you have some CA, are you happy with the purchase?
Mark
oman321
08-22-07, 07:50 AM
Mark I noticed 10 looked funny but it was zoomed somewhat I started with 51.5 width and got it to 68.5 with the prisms. If you notice the tower on the left the tower looks like my original pic 8. Also I didn't get the exact frame shot as the plane is a little higher up on the screen.
He-he, ya theres some sag in my bed sheet:D, no frame to line up yet still in costruction. Used a tape meausure last night where as the original pics were just eye balling. This was all setup for my sons b-day party and I have taken advantage of it for testing. It's not perfect but the kids had a blast. Also I needed a clamp that was supporting the center a little better. Luckily it doesn't sway too much.
Voicecoils,
Good job, sorry to hear about the chip but it doesn't seem to be a problem.
You might want to put the prisms on a hard surface and then use something like shims to slightly tip the prisms, this helps to square things up like MUPI mentioned somewhere above. FYI I was projecting from below so I had to slightly tilt up from the front.
He-he, ya theres some sag in my bed sheet:D, no frame to line up yet still in costruction.
It is amazing how much easier it is to do when your screen is 2.37:1. The other thing however is that your native 16:9 image (lens removed) also needs to be spot as well, so allot easier with side masking panels as well (which I don't have yet) either.
I was going to ask how do you intend to correct the pincushion, but having another quick look at your images and it seems your free of the problems for now. If it does cause a problem, will you curve the screen or simply projector that onto the side masking when you construct your screen?
You can see my ongoing AT project in this post HERE (http://www.avsforum.com/avs-vb/showpost.php?p=11343680&postcount=15)...
Mark
oman321
08-22-07, 11:02 AM
I Wanted to ultimately have a curved screen If I go with 2:35, if anything for the look of it but also to address any pincushion. I have a contact for a local metal fabricator that I hope will be able to help. Like you said it doesn't seem to be an issue at the moment at the sides but I do notice a slight curve at the bottom you might notice on pic 4 in post 62. Much more pronounced on voicecoils streched pics but his prisms arn't tilted which helps to square things up.
I'm kind of torn because if I do a 2:35 screen I will have a small 16:9 screen where as If I do a large 16:9 screen I can still do a large 2:35 screen. That's why I was excited to be able to make V. Compression image work. I hope to put my projector back to where I was testing originally make a different enclosure for vertical and see if it works from there. I can then use the full panel and come up with a masking system.
I've seen your progrees Mark, good stuff I like your solution for the speakers & AT screen. I've also followed your progress with the Aussie Lens, impressive work. One of the many reasons i'm glad your chiming in to help out.
As a side note I put the coated sides of one of the prisms towards the projector lens to see how much light shines through... nothing but blackness.
crocowhile
08-22-07, 01:45 PM
Thank you oman321. I found the thread on the french forum, I'll try to keep up with them.
voicecoils
08-22-07, 06:57 PM
Yes, the projector must be positioned perfect first. Any off setting in the projector will only be magnified by the lens.
Mark
Yes I will need to find a proper home for the PJ, centered with the screen.
In your experience, is projector height relative to the screen a critical factor? In other words, is the best image achieved with the projector lens at the centre of the screen?
I could potentially put the projector on a shelf directly over my head (centre of the screen height and width). But if it's not a big issue it would be more convenient to have it higher up (especially for playing Wii!).
So you will be able to correct the pincushion, and you have some CA,
Does position of the prisms relative to the projector, position of the projector relative to the screen, position of the prisms relative to each other, and/or zoom affect CA?
are you happy with the purchase?
At half the price of the next cheapest options I know of, I'm quite pleased with an AR coated optical glass product.
But, if the prisms only cost $8 each from surplus shed (like their other prisms) then the price the group buy paid seems a bit high. Still, I've not no regrets even though my girlfriend doesn't seem so impressed so far :rolleyes:
Yes I will need to find a proper home for the PJ, centered with the screen.
In your experience, is projector height relative to the screen a critical factor? In other words, is the best image achieved with the projector lens at the centre of the screen?
I could potentially put the projector on a shelf directly over my head (centre of the screen height and width). But if it's not a big issue it would be more convenient to have it higher up (especially for playing Wii!).
It will depend on the projector, but most home theatre projector work off one plain (either top or bottom) depending on how they are mounted. You need to mount the projector as straight as you can (no key stoning), which generally means flush to either the top or bottom...
Does position of the prisms relative to the projector, position of the projector relative to the screen, position of the prisms relative to each other, and/or zoom affect CA?
Not really, CA is caused by the first prism as it breaks the (white) light into a spectrum. The second prisms can reform this light back to white light, but only when the two prisms are set up like a pass through mode. Because the placement of the prisms is staggered to form the anamorphic stretch, the light never quite reforms and the results are CA or colour fringing at the edges.
The only way to correct this is to use a second set of prisms made from a different type of glass that is then bonded to the first set to form an achromatic doublet - which is one project I am working on.
At half the price of the next cheapest options I know of, I'm quite pleased with an AR coated optical glass product.
But, if the prisms only cost $8 each from surplus shed (like their other prisms) then the price the group buy paid seems a bit high. Still, I've not no regrets even though my girlfriend doesn't seem so impressed so far :rolleyes:The cost is relative to the size of the prism (the amount of glass used), the type of finish, optic coatings etc. He would have had to have a minimum order as well to get his price down. I bet they cost more $8ea, mine are way more than that even when buying in bulk...
Mark
oman321
08-22-07, 10:10 PM
The $8.00 prisms are not the same, these are special ordered and a little bit bigger.
I made a vertical enclosure and took some pics. The first 2 pics are the prisms positioned as I showed above, this works but I had to reposition the lens on the projector. I had better results by positioning the enclosure as in the third pic (upside down basically)for less proj. lens adjustment.
oman321
08-22-07, 10:15 PM
This is the result of before, stretch, compress.
mine arrived this afternoon.
small chip in the corner of the smaller prism, despite being very well packed :( may need to talk to sam about it if it affects the image.
this is a very high quality DIY product and I'm happy I made it into the group buy!
pics to follow soon...
I also found a chip at one corner of one of the prisms. Just a coincidence
that you also noticed the same. It is at the corner so it doesnt affect the image I guess.
I havent yet tested the prisms with a DVD. But looking at the pictures and not much feedback here, I dont have high hopes. So most likely I might sell my pair of prisms but of course it has a chip.
voicecoils
08-23-07, 01:45 AM
I also found a chip at one corner of one of the prisms. Just a coincidence
that you also noticed the same. It is at the corner so it doesnt affect the image I guess.
I havent yet tested the prisms with a DVD. But looking at the pictures and not much feedback here, I dont have high hopes. So most likely I might sell my pair of prisms but of course it has a chip.
No need to have such poor confidence :) Most of us need to build an enclosure and continue adjusting before reporting back further. Have you looked through the HCFR threads or the Commandes-groupee ones? More then 165 people have these exact prisms now (most are french) and the continued interest on french forums for group buys should instill some confidence :)
I'm not too upset about my chipped lens, the package WAS very well packed, but the contents are delicate and it did travel well over 8,000 miles :eek:
I plan to better position my projector, get an enclosure made, and report back with some more pic's.
I suppose DIY is not for everyone and DIY anamorphic lenses are really still frontier HT territory (although heaps of hard work has already been done by CAVX, diyaudio.com, french crew etc).
snowkirk
08-23-07, 02:26 AM
I built an enclosure and tried these prisms. Got a rectangular image and noticed slight pincushion in the middle. For the money paid, I am satisfied. I will probably be able to take it to my friend's place and test it against his properly ceiling mounted Optoma HD80.
Mupi - if you are selling ur extra prisms, send me a pm, I can check with my friend if hes interested.
oman321
08-23-07, 09:10 AM
Don't fret Mupi,
People are still setting things up, I was just kind of anxious because I have a temp set up that needs to come down. The pics have been better than I expected, I tried to capture what I'm seeing but the pics never do what your seeing justice. Also, like we mentioned above pincushion on the sides hasn't really been an issue as you often find on a anam. prism setup
I looked last night and found a tiny chip at the corner of my large prism doesn't affect the image at all.
I was trying to look through the French site to see if they had any new developments with the prisms coming in and one guy got a prism that had a one inch chip with crumbled glass.
oman321
08-23-07, 09:52 AM
Snowkirk,
I meant to request pics of what you did. Did you go with something similar?
snowkirk
08-23-07, 10:11 PM
Oman,
I did one similar to yours(thanks for the details). I will test it with my friend's Optoma HD80 and see how it looks
well I tested the prisms today with a DVD.
I noticed that the focus wasnt as good as the image without the
prism. I also noticed that all 4 edges werent straight at all. They were
bowed and I couldnt get them straight. I also tried to reduce the
zoom on my IN72 but I still got the bow. Already the image isnt that
big. The 16:9 image is only 35mm tall. The 2.35 image is about 83x35mm.
Not a bad 2.35 image size but the clarity wasnt there. I also felt that the
bigger 2.35 image wasnt as bright as the smaller 2.35 image (i.e the one inside
the 16:9 area with black bars).
BTW is pincushioning same as the bowing of the edges?
I can see CA as the edges are not sharp. There is a bluish ghost kind of thing at the
left and right edge. But that can be managed using black borders.
Anyway... I might try a couple of more time this week end. I dont think the
image is going to get sharper. At least if I can find a way to keep the edges straight
I could live with it. My projector placement is fine because the 16:9 image is perfect.
If I have to zoom down all the
way to get rid of the bow then there is no point doing it because the image size
will be too small. I would rather watch a larger 2.35 image with bars than a tiny not so sharp one without bars :-)
The images in the other thread (crystal factory prisms) seem to be a lot
better. They seem to have perfectly straight edges.
Now I know why the commercial lens manufacturers strive for perfection.
Just curious: The Sams prisms I got were shipped by surplusshed in PA. The lower right corner of the receipt was cut and removed.
They also sell a lot of optical stuff including the $8 prisms. In fact I bought those $8 prisms from ebay and
since the concept worked I wanted to try bigger ones. I tried the Masillion Plaque
prisms but they gave a lot of reflections. Sams prisms also give reflections but they
can be eliminated with an enclosure.
So are these so called Sam's prisms nothing but prisms from surplusshed?
Why were they shipped from surplusshed?
Why was a portion of the receipt cut and removed?
Final note: after my final testing this weekend if I still feel buyer's remorse :-)
I will be selling mine. Like I mentioned and like others have mentioned there is
a tiny chip at one corner of one of the prisms. I paid $126.80. I will sell them for
$110. I guess I can pay for the shipping with in US if it is like 10-15 bucks.
My friend has not seen the prisms. If he also decides to sell after watching the image, will let you guys know. I dont like to put it on ebay as I dont want to explain all this story. People here already know the story so I dont have to explain :-)
BTW is pincushioning same as the bowing of the edges?
Yes, where the centre (vertically) is not as tall as the edges, and same happens horizontally as well, though not as obvious...
Now I know why the commercial lens manufacturers strive for perfection.
Yes there is a bit more to it than just stretching the light which is why the commercial lens cost so much more - correction elements etc...
So are these so called Sam's prisms nothing but prisms from surplusshed?
Why were they shipped from surplusshed?
Why was a portion of the receipt cut and removed?Maybe he had them amde there and it was easier (more cost effective - shipping was included) to have them dispatched from there rather than paying freight to France (including an import fee), then having to mail prisms back to the US...
Mark
oman321
08-24-07, 08:02 AM
Mupi,
I wish I had taken a pic of my shimmed and tilted original enclosure. Based on your finding I tilted the enclosed prisms to best square things up, also during the tilting it seems to help the CA on the left and right. Only the best Lens' will be able to effectively deal with this. Unless Mark comes up with a DIY solution.
At times when I was taking the lens in and out I slightly had to refocus to achieve the best picture. I would mostly notice when there were words or the menu on the screen.
I am not certain but when I saw the packing slip, I assumed that this is where Sam ordered the prism's from. They advertised shipping to anywhere is $5.00 and this is what Sam added for shipping I believe. They are special ordered from what I can gather from translating the French site. The piece removed from the packing slip is probably a factory confirmation of one pair or 2 pairs etc... being placed in the package on a specific order. Good luck with your the rest of your testing, I gotta get back to construction.
BTW you got a better exchange rate than me, I ended up paying $135.00:(, that's ok for the price I think they're good:)
Gerry S
08-24-07, 11:49 AM
Was there an item number or SKU on the packing list?
oman321
08-24-07, 12:04 PM
If I still have it I'll check tonight, but you gotta have 50 produced to get them thus the reason Sam organized the unauthorized group buy.
Was there an item number or SKU on the packing list?
There is some item lookup code which is L9513D
I guess Samy has some explanation to do here :-)
BTW in the picture posted by OMAN321 (010.jpg) I dont see any pincuchioning
or barrel distortion. If my picture was as rectangular as 010.jpg I would accept it.
OMAN321: did you have zoom turned all the way down.
It is also possible that not all the prisms that Samy made are identical.
I am also surprised to see the ampunt of reflections from a coated prism.
It is not as bad as the Masillion Plaque prisms but for a coated prism
it seems too much. Well cant complain for $126.80.
I just wish that the image were rectangular. I can also live with CA.
oman321
08-25-07, 09:56 AM
Mupi,
I tried searching Surplus shed with that item number, nothing came up.
As far pic 10 I was I had zoom set to a little less than a 1/3. You'll definately need an enclosure and depending on projector placement you'll need to tilt the enclosure to square things up.
FYI: At Lowe's I saw a place mat in the cabinit area I might have used instead of the cork board if I had found that first.
Gerry S
08-25-07, 01:12 PM
There is some item lookup code which is L9513D
I guess Samy has some explanation to do here :-)
Thanks! As someone else said nothing came up. Oh well...
1Sharpdog
08-28-07, 03:44 PM
I got my french prisms yesterday, they were packed great, and in perfect condition. I made a first attemp to use them with my w9000 which has a huge lens, that is recessed quite far back. I got a decent picture on the screen, but because the light was sooo close to the edges of the prisms, it caused some reflections to the left and right of the projector.
I need to spend more time tweeking them, as I just set them on some books infront of the projector. I was quite impressed at how easy it is to get them lined up for a 2.35 stretch. It was only about 10-15 minutes until I had the screen filled.
The onscreen image looked pretty good, but I still don't know if these are large enought for the w9000. I am going to get a little more creative with the stand, and possibly build a box. If I can't get them to work I will likely go for the ausiemorphic or bite the bullet for the 380.
Luke
oman321
08-29-07, 01:31 PM
Ok, I'm excited again about CIH.
I tested out where the screen will be ideally placed which is 21" away from the wall in false wall setup. My projector being also placed at it's ideal spot produced an image at min. zoom of 82.5". So 82.5 x 1.33 = 109.725 approx 110" width <--->. My room is about 11'.5" wide, but hey that still leaves a foot+ on each side so plenty of space.
The 82.5" 16:9 screen is approx a 95" screen diagonally which is a good 16:9 screen for the room. The Mrs. thought a 100" which resulted in 115" diag. was just to overwhelming. So this results in a 2:35 screen which is 119.5" diag. So im back in with Horizontal Expansion it would seem, it will be more definative as I near completion of the room.
My room is about 11'.5" wide, but hey that still leaves a foot+ on each side so plenty of space.
At least you've got room for side masking :)
Mark
oman321
08-30-07, 10:11 PM
Hmmm... hadn't thought of the side masking. It would seem that it would fit if I make the screen borderless. My masking would need to be 13.75" and I would only have 14" on each side after a 110" screen. I think im gonna do drop down masking it would probably be a little easier to fit in and work out within a soffit above the screen.
T_MINTON
09-01-07, 05:51 AM
I was wondering if there is any interest in having a metal, powder coated enclosure, cut with a plasma cutter and precise to the french prisms? I will hopefully have a prototype within 2 weeks and I am pretty sure I can get em done very reasonably if there is any interest. Of course I will go through Alan first if it comes to that.:)
oman321
09-01-07, 08:01 PM
I'd be interested to see the prototype.
voicecoils
09-02-07, 02:25 AM
I was wondering if there is any interest in having a metal, powder coated enclosure, cut with a plasma cutter and precise to the french prisms?
I'm interested, keep us updated :)
jplmain
09-02-07, 04:04 AM
I'll support your effort.
T_MINTON
09-02-07, 09:52 AM
I am gonna do it for myself anyway. He said he could do whatever I want. SO if there is anyone that can design in autocad, he could use that to set up his plasma cutter and viola!. Otherwise I am gonna have to rely on the french site or design one myself. Since I am his Mailman, he said he could give us a good deal...lol This is gonna take a few weeks so I will start another thread when I get mine done. I need to see if I can fine a good passthrough design for those that want that option.
voicecoils
09-03-07, 02:16 AM
SO if there is anyone that can design in autocad, he could use that to set up his plasma cutter and viola!. Otherwise I am gonna have to rely on the french site or design one myself.
Perhaps a bit of inspiration:
http://www.users.on.net/~michaelcarey/pics/lens/index.html
I'm not interested in passthrough, to complicated of an enclosure, just a simple thin compact box that can be mounted to a little sled.
T_MINTON
09-03-07, 11:37 AM
I think you are right VC. I certainly wouldnt want to embellish on your design tho. But you have given me direction.thanks
voicecoils
09-04-07, 01:59 AM
I think you are right VC. I certainly wouldn't want to embellish on your design tho. But you have given me direction.thanks
Not my design, an early Aussie adaptation of the CAVX Aussiemorphic product.
With a plasma cutter a fancier or neater fitting box could be made. The example I liked to could probably be done with any metal cutting tool and a decent vise for the bend. Additionally, something bolted together could flat pack for easy shipping.
oman321
09-10-07, 12:55 PM
I think you are right VC. I certainly wouldnt want to embellish on your design tho. But you have given me direction.thanks
Any progress on your efforts T_MINTON? Any ballpark figures of what your source might be able to get something like this done for?
T_MINTON
09-10-07, 06:59 PM
As I mentioned, I had to build a prototype. I have done that, sorta. I am no carpenter or designer. I have a design that is simple so the cost will be as minimal as possible. Having said that, if you or anyone has a design that can work email it to me with measurements etc, Then I can take that to my friend and get us a quote.Otherwise, I work as aletter carrier full time and overtime, so my fiddling is on the weekend usually. I do have it up and I will take pics soon. It is crude at best but it does work well. I will keep you posted on further developements. tonyminton@gmail.com:)
oman321
09-11-07, 08:53 AM
The best I have is the designs I attached at the beginning of thread in post 5-8 from the french site. There are some good pics with metric measurements in post 8 I believe with an enclosure which can be adapted to pass through. Other then that I have the enclosure I came up with in pics on post 47 48 & 49, which is a simple wooden enclosure made of 3/8 hobby craft wood. Below I pasted a response to Snowkirk as far as the dimension of the enclosure.
quote:
I got all the material at Lowes. The cork board was a plastic backed disc for plant pots. It cut easily and worked like a charm. The prisms are nice and snug and I have held the enclosure in every direction to test out. The most important dimension is for the side panels, they measure 3 1/8" inches. Originally they measured 3&1/4 and they were sliding everywhere the 1/8th made all the difference. The cork board measures 3/16. The top and bottom pieces are 5&7/8" at the big end and 4&1/4" at the small.
T_MINTON
09-18-07, 05:31 AM
Sorry guys, still working on it.
oman321
09-18-07, 09:02 AM
No worries, we eagerly wait :D
I'm in the midst of working in my dedicated space and now that everything from my temp. setup is down things are moving along a lot quicker.
Looking foward to what you come up with, keep us updated.
T_MINTON
09-19-07, 06:12 AM
Well I have "working model" just need tobe sure I can get a full range of adjustments as far as angles. I am flying by the seat of my pants, mostly because I am not quite as smart as the EXPERTS that brought all this to us in AVS. The case should be easy enough to do but becasue everyone's install is different I will only be offering a case for the prisms and not a complete install kit (for clarification)I will post some early pics tonight or tomorrow if work permits. My folks are in from Fla. so I have been visiting.
I will be selling both the pairs. If anyone is interested please see my reply to the thread that was started a few days ago or you can also scroll back in this thread to my post about selling my prisms.
PRISM DIMENSIONS:
BTW Here are the prism dimensions as some of you had asked via PM
The first lens (one closer to the projector) is shorter than the second.
Both are of same height and angle. I dont know the angle off hand. I have
to get a calculator and compute it.
First Lens: Length 3 3/8 inch (this is the length of the slanted face)
Height 2 3/4 inch
Second Lens: Length 4 2/8 inch (length of slanted face)
Height 2 3/4 inch
PRISM DIMENSIONS:
I dont know the angle off hand. I have
to get a calculator and compute it.
20 degrees...
Mark
surplusshed
10-04-07, 04:19 PM
Hello Everybody!!!
The prisms you are all refering to where made by us - Surplus Shed
We now have them available on our website and will be stocking them on a regular basis.
Here's the link:
http://www.surplusshed.com/pages/item/l9113d.html
We only have 8 in stock right now but are having more made and they will arrive in about one month.
Please let us know if everything is described properly or if we should add anything to our desription.
Thanks!
Brent Gilson
Surplus Shed
Brent,
When using a DLP projector to play a movie there are black bars on the top and bottom (widescreen), when positioned correctly, these prisms remove the black bars by stretching/correcting the image with no distortion.
This come from your website is totally inaccurate. The projector removes the black bars through a process we shall simply call "scaling". As a result, the geometry is affected (the image appears tall and thin as if vertically stretched). When the prisms are placed in the light path (with correct alignment) they optically restores the geometry through horizontal expansion, allowing the projection of films in cinema scope the way they were meant to be seen...
Mark
oman321
10-04-07, 09:37 PM
Glad to see your carrying these as a regular stock item now. From my initial testing with these I am very pleased with the product.
As Mark says though your description is not accurate. The prisms restore the geometric shape of the image after its been stretched by the projector or a video scaler or even a dvd player or Home Theater PC. Many ways to do what's reffered to as a vertical stretch. Prisms are then used to horizontally stretch the image for Costant Image Height or in some cases Vertically Compress the image for Constant Image Width. To purpose is to get rid of the black bars and increase resolution. Also it's not only a DLP projector which you can use. It is better described as a digital projector which would better refer to LCD, DLP, LCOS, SXRD, etc...
surplusshed
10-05-07, 10:19 AM
Thanks for the info guys!
Our website is updated every Sunday so we'll make the corrections then.
Sometimes we just make optics for people and have no idea what they are using them for..
oman321
10-05-07, 10:35 AM
Check out the 2:35 main forum, this is a subforum of that section. In particular check out the the "official 2:35 screen picture thread" which is a sticky at the top. It will show you what people are doing with different prisms and lens setups.
Just a word of caution though, technically your not able to come on to the forums to sell your products. So while it's nice to let everyone know it's available to the masses, check out the forum rules for what you can and cannot do.
Now that I stated that, is it possible for you guys to create slightly larger(taller) prisms. Just curios, my prisms are fine for my projector, but the lens' don't work on every projector due to their size.
surplusshed
10-05-07, 02:38 PM
We can make bigger prisms but it will require at least 50 to be made.
If you can spark some interest and get at least 25 people to commit to an order, we can have them in production.
We would need detailed specs with a drawing if possible. From there a sample would be made, sent to you for approval, then a 25% deposit would be needed to start production.
Our email is: surplushed@aol.com all specs would go there.
We saw there were quite a few people looking to get the prisms and we just wanted to let them know where to get them. Sorry for any misunderstanding.
oman321
10-05-07, 03:24 PM
Cool,
For me the existing prisms work, but for others who might be interested it's nice that it's possible. I believe all the dimensions other than the height would be the same. The idea is for the projectors beam to be able to fit inside the prism area without being obscured by the AR coating. Right now the prisms are about 2.5" tall they would need to be about 3.5 to 4" tall for them to work with most projectors.
Don't get me wrong, I'm quite pleased to know that you're making the prism's more regularly available (especially if something happens to mine by accident), just didn't want for you to get in trouble with the forum moderators. It's a great place for people to learn, trade information, get ideas, etc... but they have rules about commerce to make it fair to their sponsors. Like I said check out the various 2:35 threads to get an idea of what people are doing.
WARNING: this is an addictive hobby/way of life and you will quickly find yourself looking at AVS every chance you get with a computer. You have been warned.:D
The the chat on anamorphic lens home made cinema scope screens and masking systems. NOTE...Not for people looking to sell their products.
We can make bigger prisms but it will require at least 50 to be made.
If you can spark some interest and get at least 25 people to commit to an order, we can have them in production.
We would need detailed specs with a drawing if possible. From there a sample would be made, sent to you for approval, then a 25% deposit would be needed to start production.
Our email is: surplushed@aol.com all specs would go there.
We saw there were quite a few people looking to get the prisms and we just wanted to let them know where to get them. Sorry for any misunderstanding.
Be careful, because Sam got banned for the Same thing. Did you check your PM?
Mark
oman321
10-11-07, 03:22 PM
T_MINTON,
Any chance of seeing that prototype? Any update as far as your contact being able to produce the enclosure?
Thanks.
Hello Everybody!!!
The prisms you are all refering to where made by us - Surplus Shed
We now have them available on our website and will be stocking them on a regular basis.
Here's the link:
http://www.surplusshed.com/pages/item/l9113d.html
We only have 8 in stock right now but are having more made and they will arrive in about one month.
Please let us know if everything is described properly or if we should add anything to our desription.
Thanks!
Brent Gilson
Surplus Shed
So what exactly is the type of glass used.
Any reason why the prism ruins the focus of the image. I agree that these
prisms could be expected to cause distortion to the edges of the image but at least if they do not affect the focus it might be worth as a cheap alternative for CIH.
BTW: I still have one more pair left. It has a little chip at one corner but it
does not affect the image. I bought this through Sam for $126 (yes it was shipped
from surplusshed, PA)
Asking $95 + S&H. I sold one to a guy in Canada. The UPS cost to Canada was $12.
I would presume it would be under $10 within US.
I am sure the prisms that you buy from Surplus Shed would also have chips
like others here had reported :-)
So what exactly is the type of glass used.
Any reason why the prism ruins the focus of the image. I agree that these
prisms could be expected to cause distortion to the edges of the image but at least if they do not affect the focus it might be worth as a cheap alternative for CIH.
BK 7 @ 20 degrees...
Mark
oman321
10-16-07, 08:35 AM
So what exactly is the type of glass used.
Any reason why the prism ruins the focus of the image. I agree that these
prisms could be expected to cause distortion to the edges of the image but at least if they do not affect the focus it might be worth as a cheap alternative for CIH.
Mupi have you tried any other lens system?
I have read before that others need to slightly refocus their image when using a prism based lens. Not sure if that's the norm or not but I have very good vision and from when I was testing I can't recall it being a major problem. I might have needed to very slightly adjust to re-focus.
I have read before that others need to slightly refocus their image when using a prism based lens.
You shouldn't have to refocus the image if your moving the lens in/out of the
light path, but once focused, you may notice that the image is sharp in the centre and then progressively becomes less sharp towards the edges. Some of the loss in focus could be due to the CA that is virtually 0 in the centre and increases towards the edges.
Only corrective elements can fix this...
Mark
oman321
10-16-07, 09:32 AM
Now that you mention that, it think it was someone switching from stretch to passthrough mode that was having issues. I still think the image looks good/great for the cost.
And again, only corrective elements can fix this...
Mark
Mupi have you tried any other lens system?
I have read before that others need to slightly refocus their image when using a prism based lens. Not sure if that's the norm or not but I have very good vision and from when I was testing I can't recall it being a major problem. I might have needed to very slightly adjust to re-focus.
Nope I havent tried other lens systems. I had the Mallison prisms but
I returned them as they caused too much reflection.
With the French prisms I had to adjust the focus a bit. Not that the image was blurry but it wasnt as sharp as the image without the prism. The image without the prism is so nice that I could not live with the image with the prism even though it is only $126. So I decided to get rid of them. I have already sold one pair. The second one is up for sale.
I guess people should stop selling all these cheap crap claiming that they can be used as anamorphic lens. There is no way a DIY lens can beat the image from the commercial lens.
If the size of the 2.35 image is the only thing one cares about, then these cheap options may be ok but just bigger isnt better for me. I would rather watch a small but prestine image straight from the projector than a big but lousy image through the prisms.
BK 7 @ 20 degrees...
Mark
well you and I think they are BK 7. what is the guarantee that those pieces of glass are in fact BK 7. They could be just as bad as any other $8 prisms they are selling. I also doubt if they are coated considering how much they reflect. They arent as bad as mallison prisms but for coated prisms they put out an awful lot of reflections.
well you and I think they are BK 7. what is the guarantee that those pieces of glass are in fact BK 7. They could be just as bad as any other $8 prisms they are selling. I also doubt if they are coated considering how much they reflect. They arent as bad as mallison prisms but for coated prisms they put out an awful lot of reflections.
BK7 is pretty much the same as Crown Glass and is optically clear and not that expensive which is why it commonly used. Allot of the final image quality depends on the finish of the faces and the finer the finish, the better the result, but the more you pay. Having received quotes as high as $10.5K for four BK 7 prisms, would suggest that $126 is indeed entry level. It is not to say that those prisms could not be polished to much higher spec, just the price would go up dramatically.
I guess people should stop selling all these cheap crap claiming that they can be used as anamorphic lens.
No, one should not expect ISCO III performance from just 2 prisms that cost just $126.00. The 2 prisms lens works to a certain level (entry) and has been well documented to have faults - CA and some focus). It has just 2 elements after all, and it needs at least 5 (CA correction as well as focal correction) to qualify as "high end" product and you can be assured that even from a DIY end, it will cost way more than $126.00 in parts alone...
Mark
Steve Scherrer
10-18-07, 10:07 AM
I guess people should stop selling all these cheap crap claiming that they can be used as anamorphic lens. There is no way a DIY lens can beat the image from the commercial lens.
Wow. Pretty high expectations for $100 anamorphic lens.
The fact is, these CAN be used for an anamorphic lens. If you want commercial quality, please buy a commercial lens--they have all kinds of correction features.
But these prisms in the DIY system get you MOST of the way there at a fraction of the cost.
(As an aside, Mark did a shootout against a commercial lens, and the DIY lens fared pretty well).
Anyway, I am sure my standards are a heck of a lot lower than yours. Personally, I don't really put all my faith in testing grids that demonstrate focus issues or CA. My standard is at the "movie watching" level. Once a movie starts, do I notice the slight focus issues or the slight CA? With the masking, do I notice the pincushion effects? Hardly. Am I pleased with the DIY lens? As punch.
Wow. Pretty high expectations for $100 anamorphic lens.
In fact if you could find the screen shots Sam posted, you could see the defocus at the edges...
Mark
Bruce Wayne
12-12-07, 02:41 PM
You mention defocus due to CA toward the edges. I am planning to buy prisms for a diy constant width setup. I am using an IN72 480p unit to do the scaling. If the image resolution is increased by using all of the pixels, shouldnt the defocus be virtually undetectable from normal seating distances? As well as CA for that matter.
I get so confused reading all the post, one guy says he can live with CA and the other says he cant because it's so bad, yet they never tell the distnace they are making these judgements by. Is one guy looking at the screen within 12" and the other 12' ? I think every opinion should state setup, distance viewed, size of screen and equipment used. Of course a DIY lens will look better on a 1080p rs1 compared to a 480p in72. Just think it needs to be a little more structured comparison wise before you bash it or praise it.
RandyFreeman
12-14-07, 03:31 PM
A real big factor for the amount of CA in the image is the zoom setting of the projector lens. For the best results you need to position the projector as far from the screen as possible and set the projector lens to the smallest zoom setting. The less angle that the light leaves the projector lens the better.
Randy
A real big factor for the amount of CA in the image is the zoom setting of the projector lens. For the best results you need to position the projector as far from the screen as possible and set the projector lens to the smallest zoom setting. The less angle that the light leaves the projector lens the better.
Randy
Or if you can, calculate a pre-set TR - say 2.0:1 (screen height x 1.78 x distance from screen to projector). That way you know that CA will be reduced...
Mark
Hi Folks. I'm a new member with interests in anamorphic screening since I just acquired a Panny AE2000. I found this thread and was hoping for an easy way out with the prisms mentioned. I worked as a projectionist in my early days and used a couple of the high end prism based anamorphic add-ons for Cinemascope films (these went on the front of the main projection lens). These were simple coated prisms similar to what is being discussed in this thread BUT they were achromatic prisms. Each of the two prisms consisted of two slabs of glass cemented together (Crown and Flint) to correct for color dispersion, which may be largely responsible for the poorer performance some of you mentioned in this thread (sometimes what appears to be defocusing is really a color dispersion problem). Positioning of the prisms relative to the front element of the projection lens is also important to get the best results.
I started work designing a pair of cylindrical mirrors to accomplish the anamorphic squeeze or stretch (without the achromatic errors refractive elements introduce) but that is really only in the early planning stage right now. If I ever get on with that, will report my results. Just thought I'd mention the former though since non-color corrected prisms are famous for what they're used for - to disperse the colors in a light beam and make rainbows.
T_MINTON
01-06-08, 07:51 AM
OMAN and the rest, sorry I have been away so long but my life has been in a bundle. I was rear ended in my postal vehicle and was off luckily a week then the holidays...I am still working on it and was sidetracked building my curved screen(which I love) SO I plan to get to my bud's place and see what he could do.
oman321
01-06-08, 07:49 PM
Thanks RBTO, looking forward to what you come up with.
T_Minton no worries, I'm still in the midst of construction and have also been working on a star panel for a skylight effect. These things always take longer or often get further sidetracked than we anticipate.
Is there any place to get DIY plans for an anamorphic lens? Just got my HC 4900 up and running and was thinking about giving it a try. Just doing zoom now and picture looks good to me. I would only imagine that a lens would make it that much better.
oman321
01-15-08, 10:20 AM
No actual plans available that I know of. If you want to try it out and see what the difference will be for you Surplus Shed is a good place to start for cost effective lens'.
Also see CAVX for a reasonable DIY venture with less DIY on your part.
All I can offer is the pics in this thread attached early on and descriptions of what I did early on when I got my prisms'. Hopefully soon I'll be able to get back into it.
Thanks Oman. How do you figure out what the angle of the prisms in relation to each other should be?
oman321
01-15-08, 12:17 PM
Go to post number 5, the fist image attached is a CAD drawing I believe, which someone from the french forum had done. What I did was print the image, and then reduced it to about 90% if I recall correctly, this allowed for it to be just about the same size of the actual prisms. I then cut it out and placed it within my enclosure to get the correct angles. They are pretty accurate but might still require a little tweaking. Also the lens assembly required some slight tilting to get a squared image.
If I recall here or I might have read it somewhere Mark (CAVX) suggests to basically project your 16:9 image and then place the lenses in front to expand it to 2:35 and basically one prism adjusts the left while the other adjusts the right. Of course you either need to have a 2:35 screen already or measure how big a screen you would get and mark off with tape. i.e. 90" wide <----> screen 90 X 1.33= 119.7. Likely rounding up to 120".
I went to "Surplus Shed" web site & found nothing when I searched for "French prism". Is there a part number or have stopped selling them ?
Thanks!
Person99
05-15-08, 04:49 PM
I went to "Surplus Shed" web site & found nothing when I searched for "French prism". Is there a part number or have stopped selling them ?
Thanks!
I think they call them something like "large anamorphic prisms pair".
oman321
05-22-08, 09:12 PM
I went to "Surplus Shed" web site & found nothing when I searched for "French prism". Is there a part number or have stopped selling them ?
Thanks!
Here's the link on their site.
http://www.surplusshed.com/pages/item/l9113d.html
Person99
05-27-08, 11:39 AM
These prisms seem to perform as well as any 2 prism based lens in most respects (and actually better than most in terms of focus).
But, the problem I'm noting is bad ghosting. This is easily seen with white text on a black background. For instance, the credits (like the "Hasbro" one) at the beginning of Transformers. This is the only aspect of these where their performance seems less than other two prisms systems.
Ghosting is caused by internal reflections and the angles of the prisms not great enough to move the ghosting off screen. It is true that these prisms operate at a much smaller angle than other two prism systems (which is why they can be so small).
I'm assuming this ghosting cannot be eliminated because it is a product of the angle of the prisms, but has anyone figured out anything I may have overlooked?
Thanks.
speedtriplex
05-29-08, 11:35 AM
can anyone tell me what material is the corrective element made of? how thick should it be? and can one be made and put in a typical DIY 2 prism based anamorphic lens? or is it some special material that is too expensive to have for a DIY lens?
Person99
05-29-08, 12:16 PM
can anyone tell me what material is the corrective element made of? how thick should it be? and can one be made and put in a typical DIY 2 prism based anamorphic lens? or is it some special material that is too expensive to have for a DIY lens?
I'm assuming you are talking about the astigmatism correction element? If so, I've never seen anyone use one in DIY.
To me, the biggest issue with DIY is the CA. For that, you'll most likely need an achromatic prism pair. The common approach for this is crown and flint glass, but I've not seen anyone find a source for prisms of this nature. If we could this would be the "killer app" for DIY anamorphic.
speedtriplex
05-29-08, 01:21 PM
Person99,
Thanks for your answer :-)
Yes you're right about the astigmatism correction element. CAVX is putting one in his upcoming Aussiemorphic III, so I figured why can't anyone put it too if one knows how to go about it :-)
I already have a BK7 prism pair for the lens, only want a corrective element now :-)
I'm assuming you are talking about the astigmatism correction element? If so, I've never seen anyone use one in DIY.
To me, the biggest issue with DIY is the CA. For that, you'll most likely need an achromatic prism pair. The common approach for this is crown and flint glass, but I've not seen anyone find a source for prisms of this nature. If we could this would be the "killer app" for DIY anamorphic.
As these too small ?
http://www.escoproducts.com/products/achromatic-lenses.php?show=1
Person99
05-30-08, 11:48 AM
As these too small ?
http://www.escoproducts.com/products/achromatic-lenses.php?show=1
Those are lenses. They cannot be used to create the optical stretch.
oman321
10-17-08, 10:37 AM
Well nothing ever came about with a metal enclosure, so now that my screen is ready I will be rebuilding my enclosure for my prisms. I already have some 1x6 lumber that I will be using this time around vs. 3/8th stuff I used before. The enclosure before was stable and all but driving the screws in to the side side panels and very close to the edges of the top and bottom pieces was causing cracking.
I will be using a similar design, but I just thought of a possible modification which will make for easy adjustment of the prisms if need be.
It seems that these French prisms are quite popular so I also ordered one pair. Still not arrived but I am trying to do an article about building it to the local magazine. I am trying to make it work in short throwing distance. I can report what is the working range with panasonic ax200 if anybody is interested. I have seen the great article about the other available trophies but not with this one. Letīs see how it goes.
Person99
10-20-08, 04:35 PM
It seems that these French prisms are quite popular so I also ordered one pair. Still not arrived but I am trying to do an article about building it to the local magazine. I am trying to make it work in short throwing distance. I can report what is the working range with panasonic ax200 if anybody is interested. I have seen the great article about the other available trophies but not with this one. Letīs see how it goes.
These are not bad--no image shift, very good on preserving focus, etc. They have one fatal flaw though. The angles used means that the reflected ghost image is on the screen and it is pretty bad with these.
These are not bad--no image shift, very good on preserving focus, etc. They have one fatal flaw though. The angles used means that the reflected ghost image is on the screen and it is pretty bad with these.
I was under the impression that these had an anti reflecting coating...
Mark
oman321
10-21-08, 09:53 AM
They do, I have not any reflection issues, nada, zip. Even putting the coated side of the prism directly into the projector's beam produced nothing but a shadow.
I just noted what you said about the lettering reflections Person99 in your earlier posts from May. We saw Indiana Jones this past weekend with the lens in place, and their were a couple fo scenes with lettering at the bottom of the screen at the beginning, neither my family members (my toughest critics) or I noted ghosting letters. Also we've watched some baseball and football and no problem with the tickers or score boxes. Tonight I wanna try and get some screen shots hopefully so I will try and look for that, even though I may not want to;) perhaps in closing credits.
In any event I made some progress on my updated enclosure. As I noted earlier an idea quickly came to me of how to easily access the lens to make quick adjustment and clean the lens' if need be. In the pics to follow you'll see how I'm doing this. I did re-use the corkboard from my last case as it is a good way to hold the lens' in place. I might still change that out for this padding you put in your kitchen drawers to hold holds things in place, but we'll see.
Here is a pic of all the material it is composed of
http://i240.photobucket.com/albums/ff231/oman321/Lens001.jpg
As you can see I already hinged the top cover
http://i240.photobucket.com/albums/ff231/oman321/Lens002.jpg
Then with everything put together
http://i240.photobucket.com/albums/ff231/oman321/Lens003.jpg
Open-says-me
http://i240.photobucket.com/albums/ff231/oman321/Lens004.jpg
Profile view
http://i240.photobucket.com/albums/ff231/oman321/Lens005.jpg
http://i240.photobucket.com/albums/ff231/oman321/Lens006.jpg
Latches attached, lens' in place for test closing
http://i240.photobucket.com/albums/ff231/oman321/Lens007.jpg
Success :D
http://i240.photobucket.com/albums/ff231/oman321/Lens008.jpg
For size reference I put a PS3 game next to it
http://i240.photobucket.com/albums/ff231/oman321/Lens009.jpg
http://i240.photobucket.com/albums/ff231/oman321/Lens010.jpg
http://i240.photobucket.com/albums/ff231/oman321/Lens011.jpg
In front of projector
http://i240.photobucket.com/albums/ff231/oman321/Lens012.jpg
http://i240.photobucket.com/albums/ff231/oman321/Lens013.jpg
http://i240.photobucket.com/albums/ff231/oman321/Lens015.jpg
It was at this point that I discovered because of the thickness the wood the prisms were being raised just a little bit to much so I had to cut it down. I basically sliced the bottom panel in half. It was a pain but I got it done, late though so that's why no screenie pics yet, hopefully tonight.
http://i240.photobucket.com/albums/ff231/oman321/Lens014.jpg
http://i240.photobucket.com/albums/ff231/oman321/Lens016.jpg
Need to sand that bottom panel a little more to smooth out the rough cut, lightly sand the hardware and spray the whole thing black for a finished look. I really like the hinged approach as it made it simple to be able to re-positon the prisms and then lock it down. This way I could also get quick access if need be to dust off the lens' from time to time.
Widlarizer
10-21-08, 10:17 AM
Hi Oman321,
as i see, you use the same epson projector like me, which has no possibilty for vertical stretch. So my question, how do you stretch the image? HTPC? Or external video processor?
Person99
10-21-08, 10:27 AM
They do, I have not any reflection issues, nada, zip. Even putting the coated side of the prism directly into the projector's beam produced nothing but a shadow.
I just noted what you said about the lettering reflections Person99 in your earlier posts from May.
Even coated prisms will have some reflections (look inside the case and see the reflected image).
Couple of observations. If you have an LCD projector which has a poor panel CR, you might not see the ghost image that bad because either the black is too gray, or the white text is too dim. I see them on a PJ with a calibrated (tested) ANSI CR average of 650:1 and a peak ANSI CR of 900:1 with about 400 ANSI lumens. A dimmer projector or one with worse ANSI CR may not reveal the issue.
Secondly, after looking at your pictures, I can say that I've tested with the prisms much closer together (almost touching like Mark and others set up their lenses) whereas you have them spread out much more so the reflection may hit the inside of the case instead of bounce back out. I will try increasing the distance between the prisms to see if this eliminates the on screen reflection. I'll report back after some testing.
oman321
10-21-08, 12:35 PM
Widlarizer,
I got the discontinued Key-Digital 4x1HDMI (http://www.digitalconnection.com/products/video/kdhdmi4x1.asp) available at Digital Connection. I was able to get it at a slightly better price over what they are advertising it now for. Price has gone down, up, down, up recently so maybe wait a while if you decide you want it. It's great for a 720P projector and forum user ebr uses it with 1080P projector. The only down side is that it doesn't accept a 1080P signal(though it does output one) and it doesn't do 24fps.
Person99,
That would be cool if you could test that out. I have the Epson HC400 not calibrated and the manufacturer's specs say 5000:1 CR, 1500 ANSI Lumens. I know this is spec sheet ratings and not real world tested, calibrated, and properly setup numbers, it's just to let you know what I have and what the spec sheet says. Link (http://www.visualapex.com/Epson/Projector-Specifications.asp?For-The=PowerLite-HC400)
As far as the positioning of the prims, I was testing out my screen on friday and threw my old enclosure back together to align things. I first started with a print out of the schematic that I posted early on in the thread where the lens' do touch. I then needed to move the lens' in order to properly stretch the image to fill the screen. I then traced the result on the cork board that I was using for easy reference, that's just how they ended up being positioned. Maybe it resulted in an unrealized benefit, we'll see. Thanks for the feedback.
Person99
10-21-08, 12:55 PM
Person99,
That would be cool if you could test that out. I have the Epson HC400 not calibrated and the manufacturer's specs say 5000:1 CR, 1500 ANSI Lumens. I know this is spec sheet ratings and not real world tested, calibrated, and properly setup numbers
OK, if using it in one of the theater modes it is around 400 Lumens--so about what I've got. But, it has pretty elevated black levels, so you might not be able to see the ghosted image because your black level is so high (i.e. the "gray" or black is actually brighter than the ghosted image).
I'll see if the ghosted image is bright enough to snap a picture of.
As far as the positioning of the prisms, I was testing out my screen on friday and threw my old enclosure back together to align things. I first started with a print out of the schematic that I posted early on in the thread where the lens' do touch. I then needed to move the lens' in order to properly stretch the image to fill the screen. I then traced the result on the cork board that I was using for easy reference, that's just how they ended up being positioned. Maybe it resulted in an unrealized benefit, we'll see. Thanks for the feedback.
What gives the stretch is the angle between the prisms. You can get the same amount of stretch either with the prisms touching or if the prisms are 1" apart.
Person99
10-21-08, 01:07 PM
I got the discontinued Key-Digital 4x1HDMI (http://www.digitalconnection.com/products/video/kdhdmi4x1.asp) available at Digital Connection. I was able to get it at a slightly better price over what they are advertising it now for. Price has gone down, up, down, up recently so maybe wait a while if you decide you want it. It's great for a 720P projector and forum user ebr uses it with 1080P projector. The only down side is that it doesn't accept a 1080P signal(though it does output one) and it doesn't do 24fps.
If you are using it with a 720p projector (or any projector with a vert resolution up to 800), a used Lumagen DVI is a great processor. They can be had used for about $350.
In addition to the vertical stretch you'll get 11 point gamma adjustment, 4 calibration memories per input, the ability to input 1080p/24, the ability to output rates other than 50/60 Hz (if you have a PJ that accepts 48 or 72 as I do, this is great).
The biggest limitations of the DVI are no output above 800 vertical lines and no true film mode deinterlacing of 1080i (although I find 1080i film via it digital input seems to do pretty darn good most of the time with the component input being a bit weaker--but with 1080p/24 input you don't need a 1080i mode for blu ray).
For 1080p output or true film mode deinterlacing of 1080i or slightly better SD scaling, you need to step up to the Lumagen HDP which is going for around $750 used or $1000 new.
Widlarizer
10-21-08, 02:05 PM
@oman321:
Thanks for your quick answer :)
I think, that it may be cheaper for me, to purchase a new projector including the vertical stretch, instead of searching for a key digital 4x1 video scaler here in germany ;)
But you're right, beside that, the Epson EMP TW 700 is a great home cinema projector :)
Do you have any test images of your DIY anamorphic lens?
@Person99:
Thanks for your advice :) I'll have a look where i could purchase an used Lumagen DVI here in europe...
oman321
10-21-08, 02:39 PM
I'll have to try the different modes tonight and see if I see anything.
Widlarizer, If I were shopping around I probably would certainly get a projector with the V-stretch built in. At the time when I bought mine it wasn't a prevalent feature for HD signals. I know the Panasonic AX100 featured it but I didn't like all the problems that projector was plagued with. Also the Key Digital does feature a horizontal squeeze mode which allows me to leave the lens in place and get a regular 16:9 image, although 16:9 stretched over a 2:35 hasn't seemed that bad either.
I don't have screen shots yet, I will hopefully be trying to capture some tonight.
Widlarizer
10-21-08, 03:35 PM
Yeah, i already purchased the new Sanyo PLV Z700 which offers a built-in v-stretch.
But i still wanted to use my TW700 in the bedroom ;)
oman321
10-22-08, 09:49 AM
So I managed to get some screen shots yesterday. Word of warning, I don't have a tripod and I cannot set the white balance on my camera. I have a basic Nikon 4MP camera on which I turned off the flash and set the timer to take the picture. I tried propping the camera up on the back of my HT seats but it wasn't working out, so I had to hold the camera while sitting in the back row very still with both hands. Some came out better than others, some more crooked than others :p. As I'm sure most of you realize the images in real life look way better. Also reflection of the soffit area above the screen is also not an issue real life.
Indiana Jones: Spoiler alert if you haven't seen the movie
http://i240.photobucket.com/albums/ff231/oman321/screenies002.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies003.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies005.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies001.jpg
Star Wars III Revenge of the Sith
Lots of great scenes in this one, hard to choose so I gave them all to you:D
http://i240.photobucket.com/albums/ff231/oman321/screenies006.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies008.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies009.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies010.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies011.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies012.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies013.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies014.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies015.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies016.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies017.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies018.jpg
Over the Hedge, good movie.
http://i240.photobucket.com/albums/ff231/oman321/screenies019.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies020.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies021.jpg
This has got to be my favorite ;)
http://i240.photobucket.com/albums/ff231/oman321/screenies022.jpg
http://i240.photobucket.com/albums/ff231/oman321/screenies023.jpg
Person99, I was looking for the letter ghosting in different areas to no avail, including the Star Wars pics above. Then my wife and I decided to watch the most recent episode of Terminator:Sarah Connor Chronicles. After the show one of the logos that popped up on the screen was a black background with white lettering across and arched up in about 3/4's of the screen and what da you know, I saw some of the letter ghosting on the far right about 1/4 of the screen "curses". Anyhow I paused the image and started to investigate, what I discovered was that by placing my hand on the inside left side of my enclosure I was able to eliminate about 80% of the ghosting. I think by lining the inside of the case with velvet it will help to eliminate most if not all of the reflection issue. In any event the prisms are still a keeper for me, as this is still not an issue with subtitles with me.
The trophy prisms, HTB, and even the CAVX lens (no offense Mark) introduced reflection issues. I know of one person who picked up a CAVX lens second hand and was getting reflections shot back into and through out the room. Most issues were addressed by covering up the rear exposed section of the lens. For the money I am still quite pleased. I'll report back when I line the case and see if it thoroughly addresses the issues. Might be a couple of weeks though as I need to get back to work and finish the rest of my basement. Still looking foward to your results, perhaps the prism separation is taking care of some of the ghosting which is why I only got it in the far right.
Widlarizer
10-22-08, 02:14 PM
Nice pics oman321 :)
Which throw ratio do you have in your home theater. I'm asking because i would like to know how much pincushion do you get with these prisms?
oman321
10-22-08, 03:49 PM
My projector is about 14' away from the screen so 168". If I understand it correctly I'm supposed to calculate the width of my 16:9 screen which would normally be 82.5". So 168/82.5 = 2.03 throw ratio?
My screen goes in about 3" from the edges. I got an excel calculation sheet from Aussie Bob which helped to figure how much curve I needed. Without the lens in place you can see that the edges of the image (about 6" in) don't quite make it down to the screen bottom. with lens in Place the edges make it all the way down.
Widlarizer
10-22-08, 04:30 PM
Ok, 2.03 throw ratio sounds good and i've forgotten, that you have a curved screen :)
Well...nice setup. I wish i could b