AVS Forum banner
1 - 20 of 41 Posts

·
Registered
Joined
·
1,496 Posts
Discussion Starter · #1 ·
Hello everyone,


It's been a looooong time since I've posted on here, although I do lurk from time to time. I've changed jobs and had a daughter in the meantime and both items consumed my free time and money to the point I could not obsess over my home theater.


I'm now starting to get a bit more free time, and my CRT projector/2:35:1 screen combo is looking a bit long in the tooth. It has servered it's purpose well, but the digital bug has bitten me. I've always considered it a place holder until cheaper digitals that would work well for 2:35:1 projection became prevelant. It appears we are there. So after that long intro, ISCO II owners are probably wondering what the heck does this have to do with me?


I have always been a proponent of anamorphic lens and 2.35:1 screens. As such I have both. A 9' wide stewart curved screen in a 2.35:1 aspect ratio ( http://www.avsforum.com/avs-vb/showt...96#post5929396 ) and a ISCO II lens that I used way back with a 4x3 LCD to get a 16x9 projected image a along time ago.


I don't have a ton of disposable income these days ( daughter remember
) so I can't really can't aford to purchase and return projectors a to find out what will work with the ISCO II lens in my setup. I've done a number of searches on ISCO II and come up with a few canidates, but I was hoping that the ISCO II owners could list the projector they are using, the size of their screen (width) and the distance from projector to screen. This would give me a great head start on what is available and if what I'm trying to do is posible.


Thanks in advance for everyone's help on this matter.
 

·
Registered
Joined
·
12,276 Posts
It's going to depend on 2 factors....1. the throw ratio you are at and 2. how close you can get the ISCO II to the actual projector lens. The ISCO II doesn't have a super large aperature, so larger is better for 1. and closer is better for 2.
 

·
Registered
Joined
·
6,440 Posts
I was using my ISCO II with an Optoma H78 DLP pj and a throw of around 2:1 (6ft wide 16:9 and pj lens at 12ft). The image was 6ft wide for 16:9 and 8ft wide for scope. The H78 had a slightly recessed lens but still worked well with the II and no vignetting. There was a little pincushion of course but that was hidden in the masking.


I tried it with a JVC HD100 to see if the II was good enough for a 1080 pj and it worked well there too. I believe there is a forum owner with a newer JVC (350 or 750) and it works with that despite the recessed lens, though I don't know what throw they are using (try the search if you're considering one of those pj's just to be sure). The longer the throw the better with anamorphic lenses so if you can get the pj at it's max throw and then move it back to get the desired 16:9 image you should get less pincushion. The only drawback is that most projector lenses don't have a constant F-stop with the zooming of the lens so you tend to end up with less lumens at furthest (smallest) zoom.


If you can get a demo of a pj take the lens with you and then you'll know exactly what to expect.


Gary
 

·
Registered
Joined
·
1,496 Posts
Discussion Starter · #4 ·

Quote:
Originally Posted by Jason Turk /forum/post/16967265


It's going to depend on 2 factors....1. the throw ratio you are at and 2. how close you can get the ISCO II to the actual projector lens. The ISCO II doesn't have a super large aperature, so larger is better for 1. and closer is better for 2.

Thanks for the information Jason!


Number 1 is my big fear here. My theater is length challenged, at only 13 feet from screen center to the back wall door. The door slides open and contains a projection portal (using theater grade glass.) This was done to keep the CRT projectors noise and extraneous light out of the room. It is possible that I could go as far back as 14 feet 6 inches, as that would fit within the confines of the marquee that also houses the projector currently. The marquee extends 16 feet total from the center of the screen.


With that said should I sell the ISCO II and settle for the zooming method of constant height? My concern there is that since my viewing distance basically matches my screen width (9 foot wide about with eyeballs about 10 feet back) I'm going to see pixel structure. The seats are now on a platform, put in place for the Buttkicker, so I could feasibly move them back a little, but probably not enough to make a great difference.


I could rework the room, moving the screen against the longer wall, which would put eyeballs and the projector at about 14 feet. This would require some major work to the room, but is possible.


What a dilemma! I'm afraid in my quest for the now, years ago, I might have painted myself into a corner



Again any suggestions are greatly appreciated.
 

·
Registered
Joined
·
6,440 Posts
Just read through your post again (should read more thoroughly!), and you may just be able to fill your screen with the pj right at the back of the marquee, but you'll need to try the lens first to see how much less than 2:1 throw you can get it, just to be sure. You'll get more pincushion at the shorter throw though.


I sold my last house with the pj and screen (buyers wanted it as part of the deal which was handy) but still have the lens, so unfortunately I can't test out a closer throw for you.


Gary
 

·
Registered
Joined
·
1,496 Posts
Discussion Starter · #6 ·
Thanks Gary, I really appreciate the input.


It's encouraging to think I might still be able to pull this off. I'm hoping that the curve of my screen will help counter act some of the pincushion.


The other variable going on here is if pixel structure on a 9' screen viewed at 10' will be visible, but I'm hoping that a 1080p projector and some softening from the ISCO II will help resolve that. Is that even reasonable to hope for?
 

·
Registered
Joined
·
6,440 Posts
Well, I've seen the JVC 750 with Schneider Cinidigitar lens from 2.4 picture heights distance (1 x screen width, 53 degree viewing angle) and screendoor wasn't an issue.


LCoS has probably the best fill factor so should allow a closer seating distance - Art Sonneborn (forum member) has a 3 chip DLP and sits at 0.8 x sw and says he occasionally sees pixels, but it's not that often, so I'd say that sitting at 1x sw or further back and you should be fine. Using the zoom method is like moving your seating closer so then you do run the risk of seeing pixels for scope. However, the Panasonic 3000 using 'Smoothscreen' technology which effectively removes the pixel gaps and has memories for both 16:9 and scope settings, so you can change ratios (auto zoom and focus) at the touch of a button.


Gary
 

·
Registered
Joined
·
647 Posts
Pixel visibility is a total non-issue with the Panasonic projectors. I have a Panasonic, and I can stand 1 foot away from a 10ft wide scope screen (with a zoomed 2.35 image) and not see any pixels at all. Some people on this forum don't like the smoothscreen feature of the Panasonics, claiming that it results in a softer picture and loss of detail, but I think it is the only way to go for a pixel free film-like picture, and reports of theoretical loss of detail with SST are just not apparent in practice- my picture is razor sharp and the picture detail seems to be solely a function of the disc quality, NOT the projector.
 

·
Registered
Joined
·
23,131 Posts
If I'm reading your info right, your 2.35:1 screen is 9 feet, that would make the 16x9 area, 6.75 feet. 2x throw from there would be 13.5 feet. 14'6" would be a bit over 2.1x.


I wouldn't sell your lens until you try it. You should be fine I think
 

·
Registered
Joined
·
6,440 Posts
I was thinking the same - only that would be to the lens, and the depth of the pj may make it a tad tight.



Gary
 

·
Registered
Joined
·
12,276 Posts

Quote:
Originally Posted by stanger89 /forum/post/16971069


If I'm reading your info right, your 2.35:1 screen is 9 feet, that would make the 16x9 area, 6.75 feet. 2x throw from there would be 13.5 feet. 14'6" would be a bit over 2.1x.


I wouldn't sell your lens until you try it. You should be fine I think

I concur...mathmatically it should work...try it to know for sure.
 

·
Registered
Joined
·
83 Posts
Hi Adam,


You have a similar theater to mine.I have a JVCHD750 with an ISCOII parked in front of it on a borrowed Stewart grayhawk 2.35 FLAT 8ft wide screen.


My throw at the moment is 2x 16.9 image,It shows about 1/2" of pincushion on the extremities,hardly even noticeble.I'm saving for a Stewart curved microperf 9ft wide.


When I finally get a 9ft wide screen I will push the lens a bit closer than the 2x recommendation as the curve screen will take care of any pincushion,there is certainly the glass there to support it.


If you park a JVC 350/750 at the very rear of your room you will be fine,probably work out to 1.9x.


What is the model # of your screen as stewart seems to only do lace and grommet curved and I notice yours is a snapper?


BTW,image is sharp as.I did try the 350 which was great and would have been more then happy,but wanted the CMS to future proof,either way you will have an awesome picture.


Cheer' Steve.
 

·
Registered
Joined
·
1,496 Posts
Discussion Starter · #13 ·
Taffman, Stranger89, Gary, Jason and Steve,


Thanks for responding. From the sound of things I have a good chance of pulling this off.


The panasonic 3000 sounds like a nice projector, but according to some hotly debated information I've read here, that it does not benefit greatly from using an anamorphic lens.


The JVC 350/750 sounds like an awesome projector. From the reviews it seems to be the first reasonably priced digital to approach the benefits of CRT projection while retaining the benefits of digitals. The price seems reasonable for what you get, so I might save my pennies to go that way instead of a cheaper 1080p digital.


Off hand I do not know the model of my screen, but I kept all of the packaging, etc. And I'm sure it will be in/on there somewhere. I'll try to get up into the attic tonight. My screen was purchased some time ago, so it is possible that Stewart no longer offers curved screens with snaps. I can tell you it was a cinch to put up and offers a very tight, well tensioned surface to project on.


Jason, I notice that AVS has some B stock JVC RS2s available. Could you shoot me a PM with price on that and AVSs price for a JVC HD350? Not sure I can jump just yet, but at least I can start preping the wife for a purchase
 

·
Registered
Joined
·
2,881 Posts
lawdawg,


I don't know if I will be much help, but I just installed an ISCO II lens on my Sony VPL-VW60 last month. I have about a 2.1 throw ratio and a 1.16 gain AT 2.37 49" x 117" screen.


I am still tweaking and next on the agenda will be blacking out the front soundstage to help with contrast.
 

·
Registered
Joined
·
1,496 Posts
Discussion Starter · #15 ·
phansson,


That helps a great deal. I'm gathering data on which projectors might work in my situation. Your info helps alot.


Hopefully with CEDIA coming up there might be even more projectors to choose from that are geared towards scope screens. Might even drive down the cost of existing projectors (JVD HD350) and I can jump on a good deal. A guy can hope!
 

·
Registered
Joined
·
83 Posts

·
Registered
Joined
·
83 Posts
When I finally get a 9ft wide screen I will push the lens a bit closer than the 2x recommendation as the curve screen will take care of any pincushion,there is certainly the glass there to support it.


If you park a JVC 350/750 at the very rear of your room you will be fine,probably work out to 1.9x.


I am going to back pedal a bit here,as I have dialled my PJ/Lens combo and with the HD750 and IscoII I wouldn't be going any closer than 2x 16:9 throw,in actual fact 2.1 would probably be ideal.

Having said that,you may just get away with it at 1.9.

The reason I am saying this is I don't think I had the lens adjusted correctly in the first instance and the image on the front lens was smaller than it is now ,indicating I could possibly move it closer.

With the lens now adjusted,I am getting quite a large image on the front of the lens and near perfect(99%) focus edge to edge on the screen.VERY HAPPY CAMPER.


Cheer's Steve.
 

·
Registered
Joined
·
3,866 Posts
I thought I'd tag onto the end of this thread rather than start another (it may help others that use the search function too
).


I've recently added a secondhand Isco II to my HD350 and Lumagen HDQ setup. I did a very quick and dirty setup last weekend as I was so desparate to see how it looked (and boy is it gooood
). However, I did already have the 16:9 non lens side of things adjusted spot on, as I'd had time to do that before the lens arrived. I'm at a long throw of around 2.7 BTW.


What I'm interested in is whether there is any adjustment that might even out an effect I'm seeing on the left side of the screen, but not the centre or right: There is a slight 'fringing' (CA?) of colour on a vertical white line so that there is a small blue 'shadow' next to it. This doesn't appear without the lens, so I'm presuming there is some adjustment I can make, although to be fair I can only see this when I'm close to the screen. My PJ's menu is set to appear on the left hand side and the text is still clear when viewed from my seat, so maybe I'm obsessing about something non important? I followed some instructions from the cineslide web site so I thought I had gone through it all logically, but any extra pointers would be appreciated. I'm going to have another go tomorrow night before viewing some more 2.35:1 BluRays.
I have already tried adjusting the astigmatism focus control BTW.


I'd been zooming and recently shrinking and thought the picture couldn't get any better. However, I'm now at minimum zoom on the HD350 and I've knocked the iris back a couple of clicks so I've gained a small but noticable increase in contrast and lost any sign of black bars (even though they were off my 2.35:1 screen, I realise now that they were still slightly lighting up the wall behind). In short I'm sold on using a lens, though an Isco III is out of the question unless I find one going very cheap somewhere.
 
1 - 20 of 41 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top