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I'm going to order my screen. I'll probably go for a Dalite pearlescent (1.5 gain) cinemacontour screen. Dalite charge a small fee to get a 16x9 screen into a 2.35 or 2.40 size. I should have it 2.40:1 right? My lens is a Prismasonic H-1200M.


For exemple I take a 58x104 screen and make them change it to a 44.3x104 or a 43.3x104 . What should be the size?


Thanks!


Bruno
 

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For video "scope" applications, that number is 2.37:1...


1.7777777 x 1.3333333 = 2.3703702 where 2.37:1 is the actual shape of the stretched light beam.


This was actually brought up before when someone asked about "overscan" when using the new Panamorph UH380 Vs the Prismasonic H1200 (H1400?) adaptors.


The owner of the adaptors in question had used the 2.35:1 screen's edges to set the Prismasonic "stretch" where the Panamorph is already "set" to 33% as it is a fixed prisms lens. As a result, the Panamorph UH380 seemed to be overshooting, where in fact, it was the screen that was not quite wide enough...


Mark
 

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It really should be 2.37 =1.78 x 1.33 (the amount the lens stretches a 16x9 image).


I think you'll be fine either way. You can always adjust the zoom to have a very slight overspill anyway.
 

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I assume I have the same problems,....since a few of hddvd or blue ray has 2.4:1, so that mean it will be black bars on top or bottom 2.35:1 aspect ratio screen??

I also ordering stewart but kind of puzzle 2.35 or 2.4 ,using pre order jvc rs-1 and isco III. I might use crystalio II or radiance(if it release by then)

Should I order 2.37:1 as mark mentions?? or 2.35:1 or 2.4:1

This stuff 're really confusing
 

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Quote:
Originally Posted by bgosselin /forum/post/0


I'm going to order my screen. I'll probably go for a Dalite pearlescent (1.5 gain) cinemacontour screen. Dalite charge a small fee to get a 16x9 screen into a 2.35 or 2.40 size. I should have it 2.40:1 right? My lens is a Prismasonic H-1200M.


For exemple I take a 58x104 screen and make them change it to a 44.3x104 or a 43.3x104 . What should be the size?


Thanks!


Bruno


Off topic, but Bruno have you thought about going with an Acoustically transparent screen, like the SMX? www.smxscreen.com


Great price and you can hide your speakers behind it.


the Lumagen is working great by the way,

Thx
 

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Generally speaking, standard "video" anamorphic lenses and adaptors are based on 1.33x (33% stretch), so a 2.37:1 screen is correct for these instances when using the full panel for "scope"...


Mark
 

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This is a bit confusing to me as well.


Stewart's CineCurve is a native 2.40:1 screen while the Cine-V, Cine-W, CineMask/VistaScope are all 2.35:1 screens!


Schneider states that its anamorphic lens attachment is 2.40:1 while at the same time saying that it is 2.35:1.




Even though the bars at the top and bottom of a 2.40:1 movie on a 2.35:1 screen would be miniscule, one would prefer to not have those bars so maybe going 2.40:1 is the better option using the projector to zoom the image to eradicate the small bars on the sides if any?
 

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Quote:
Originally Posted by Haroon Malik /forum/post/0


This is a bit confusing to me as well.


Stewart's CineCurve is a native 2.40:1 screen while the Cine-V, Cine-W, CineMask/VistaScope are all 2.35:1 screens!


Schneider states that its anamorphic lens attachment is 2.40:1 while at the same time saying that it is 2.35:1.

So average it out (2.40 + 2.35 / 2 = 2.37)


Quote:
Even though the bars at the top and bottom of a 2.40:1 movie on a 2.35:1 screen would be miniscule, one would prefer to not have those bars so maybe going 2.40:1 is the better option using the projector to zoom the image to eradicate the small bars on the sides if any?

If your using a fixed stretch optical lens like ISCO II and III or UH380, you can trim the image to best "fill" the screen and simply side mask if the 2.40 screen is too wide. The problems arise for the variable stretch (prisms based) adaptors where the screen edges are used to set the amount of stretch.


On a 2.40, the amount of stretch will be too much causing round objects too look a little flat, but worse is the 2.35 screen, where thos same shapes still look tall and thin. You more likely to notice the "tall thin" error than the slightly flat one though.




If you can not see the attached image, use the "CIH Explained" link in my signature and scroll down to the bottom...


Mark
 

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I think when talking 2.35 or 2.40 the difference is pretty small. Also even though most movies say 2.35 or 2.40, rarely are they encoded perfect on the disc. The amount of black bars will vary slightly. Thats why it's good to have a slight overscan/overspill to make sure you don't see any black bars top/bottom or left/right.
 

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Haroon Malik,


Your more than welcome



bgosselin,


It is good that you managed to find the original DIY lens project by Tor



Mark
 

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Mark,


Bruno is thinking about 104" wide screen in his 15x11.5 room, sitting about 9 feet back.


I told him to go for an SMX screen with a 2 foot deep wall. So he can have a HUGE screen and just move his row a bit farther back.


He only has 1 row, I say he will regret not going for a massive screen.


What do you guys think?
 

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Quote:
Originally Posted by CAVX /forum/post/0



On a 2.40, the amount of stretch will be too much causing round objects too look a little flat, but worse is the 2.35 screen, where thos same shapes still look tall and thin. You more likely to notice the "tall thin" error than the slightly flat one though.


Mark

Although you are correct, as always, I would challenge you or anyone else to actually notice the "tall thin" error caused by stretching a 2.40 source to a 2.35 screen. The geometric distortion in this case would be miniscule would it not?
 

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Quote:
Originally Posted by applegbt /forum/post/0


Although you are correct, as always, I would challenge you or anyone else to actually notice the "tall thin" error caused by stretching a 2.40 source to a 2.35 screen. The geometric distortion in this case would be miniscule would it not?

It might go un-noticed, but then again, it might bug the hell out of you. I have redone the photos in my blog for that exact reason. The original shots of R2D2 were not 100% geometrically correct, and after a short time, they bugged me. So after re-aligning the prisms, and learning how to better use my camera, I've taken all new shots for the page - simply click on the link in my signature...


There is a fine line between perfection and not quite there. Just keep in mind that a circle should be round not oval...


Mark
 

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Discussion Starter · #15 ·

Quote:
Originally Posted by CAVX /forum/post/0


Haroon Malik,


Your more than welcome



bgosselin,


It is good that you managed to find the original DIY lens project by Tor



Mark

I really like that thread on AVS that was deleated for legal reason.


My first link was not valid anymore, Tor lost interest in DIY lens. But I contact him and ask if he would host it again. I think DIY anamorphic lens are a very interesting project.


Bruno
 

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I made contact as well. Right now he's off flying model planes, but he seemed quite thrilled with the diyaudio thread development now using (K9?) optic crystal...


Mark
 

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Sorry but I didn't know which thread I should jump in on to ask this. Please...please help this poor math-challenged fellow.


I'm trying to decide whether to go 16:9 or 2:35:1 set up in my new room. I'm measuring how much width I have to play with on my wall. So I want to see how wide a scope screen I could set up. But I also want to know, based upon the width of my 2:35:1 screen how large a 1:78:1 image I'll end up with for non-scope flicks. So someone, please tell me what the calculation is so I can do this (again, based upon the width measurements of a 2:35:1 screen, not diagonal).


I know this calculation must be so easy it's staring me in the face but...I'm an idiot.


(At the moment I might be able to go for 91" wide screen...possibly up to 108"...but I gotta understand what size of a 16/9/1:78:1 image this leaves me with.


So the calculation formula I need is:


2:35:1 screen width = (what size) diagonal size for 16:9/1:78:1 ?


Thanks.
 

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It is easiest to deal with heights rather than widths or diagonals. Screen height x 2.35 and height x 1.78 tells you the width. 108" wide 2.35:1 screen is 46 inches high (108/2.35). 46 x 1.78 = 82 inches wide or about 94" diagonal 16:9 screen.
 

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Hey Bruno,


The guys are right about the 2.37:1 aspect size, but like you, i have a Prismasonic H1200 and I made the decision to get my screen custom sized at 2.35:1 for several reasons below.


- "Scope" movie tend to be between 2.35:1 and 2.40:1. If you do not want any overscan at all, then with a 2.35:1 screen (and a prismasonic lense) all possible aspects GREATER than that will simply start to letterbox top and bottom. If you had a 2.37:1 screen you would lose a small amount of picture information top/bottom.

Of course if you have a video processor with custom aspects to cover all aspect ratios between 2.2:1 (70mm) and 2.40:1 , then it wouldn't be a problem what screen size you got.. but that's a LOT of custom aspects and not many video processors have more than a couple. (mine has just the one dedicated/fixed 2.35:1 mode..thank you Calibre for adding that in....)


- Prismasonic lenses can easily be set to "stretch" to the exact sides of your screen. This is one of the best features of this lense series as you can set the stop points at pretty much any width between 2:1 to 2.6:1.


I would personally rather see a little bit of black bars top and bottom than lose any picture information. Granted the difference between 2.35:1 and 2.37:1 [even on a large screen] doesn't equate to much, but it can help with fixed subtitles that juuuust cross over into the darkside.


Just simply take into account the lense you'll be using, video processing abilities, your love/hate relationship with overscan and underscan and take it from there.


Matt.G
 
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