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post #31 of 48 Old 04-04-2012, 08:49 AM
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the reason I ask is I got a good deal on a curved screen awhile back and am currently saving up to try and get a cylindrical lens (hopefully an ISCO III), I was just wondering if my curved screen will be wasted with an ISCO III? Thanks for the help!
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post #32 of 48 Old 04-05-2012, 04:23 PM
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Quote:
Originally Posted by CAVX View Post

.In the end of the day, I don't want either pincushion or barrel and one reason why I leave the lens in place all the time. The other reasons are equal pixel density regardless of AR and only one calibration setting required is required. It also makes the system extremely easy to operate with a change in AR a simple push of a button.

But of course you are throwing away 33% of your 16:9 pixel density with this arrangement. I would think that would be an unnacceptable compromise to most people.
This is the 'dilemma' of using the A-lens, because you need the curved screen to compensate the geometric distortions at 2.35, but then if you leave the lens out for normal full resolution 16:9 you will get barrel distortion on the curved screen. There is no clean solution.
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post #33 of 48 Old 04-05-2012, 05:22 PM
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Quote:
Originally Posted by ojuicy View Post

the reason I ask is I got a good deal on a curved screen awhile back and am currently saving up to try and get a cylindrical lens (hopefully an ISCO III), I was just wondering if my curved screen will be wasted with an ISCO III? Thanks for the help!

2 (technical) reasons for a curved screen:

Uniformity on some materials and seating arrangements
Correction of pincushion *IF* you have a short throw ratio. Otherwise pincushion is a non-issue.

Properly designed, and implemented you can have the best of both, with or without a curve.
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post #34 of 48 Old 04-06-2012, 09:07 AM
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Scott,what would you consider a short throw?
I have a 118"X50"(viewing area)screen @ 15-16'from projector(X9).
I'd hate to have to change screen when I get the lens,THX.
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post #35 of 48 Old 04-06-2012, 09:13 AM
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Quote:
Originally Posted by GetGray View Post

2 (technical) reasons for a curved screen:

Uniformity on some materials and seating arrangements
Correction of pincushion *IF* you have a short throw ratio. Otherwise pincushion is a non-issue.

Properly designed, and implemented you can have the best of both, with or without a curve.

Agreed and I will add that there are negatives to curved screens as well. Cost for one, and with the wrong fabric/setup, it could potentially hurt your image (especially the ANSI contrast).

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post #36 of 48 Old 04-06-2012, 11:03 AM
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Quote:
Originally Posted by drummermitchell View Post

Scott,what would you consider a short throw?
I have a 118"X50"(viewing area)screen @ 15-16'from projector(X9).
I'd hate to have to change screen when I get the lens,THX.

At 15.5' that's a 2.09 TR. I generally don't spec curved screes at TR's above 2 for geometric issues, but I wouldn't advise someone to go get another screen at a 2.0 TR either. 3.0 is a nice long TR and pretty much does away with geometry issues, 1.6 could use the help, 2.0 is in the middle. Again, for geometry issues only.

And I agree with Jason. Price aside, there can be negatives. With the wrong material the screen can wash itself out depending on it's gain angles.

Without a lens, a curved screen will cause barrel distortion (bottom curves down). This is most apparent with short TR's and a ceiling mounted PJ where all of the barrel will occur at the screen bottom. A proper curve can split the error between barrel and pincushion.

That said my personal screen is a 40' radius curved FireHawk CineW, 56" tall, and about a 1.8 TR. I get pretty perfect geometry with the lens in but get barrel with lens out. It doesn't bother me. The only time I even notice is with a windows desktop if I have a HTPC desktop up. For me the curve was more about uniformity and with the Firehawk and my setup parameters, it is wonderful. love it.

So one has to look at the big picture. Room constraints, fabric choices, PJ lens issues, what kind of lens you have, width of your seating area relative to the screen size, etc. It's not as simple as a curved screen is better, or not.

We didn't talk about the personal preference factor. Some people like the look of the curved screen in the room, some don't care for it.
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post #37 of 48 Old 04-06-2012, 04:50 PM
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My throw is actually 2.1:1 and I do use a curved screen. I use mine because I have used a curved screen since DIY prisms days (2005) when I was running a 1.3:1 TR. I needed it, I had no choice but to curve. When advancing to 1080 and longer throws, I was able to wind back the curve (mine is set by bolts that pull the centre in to match the pincushion). My curve is actually quite shallow.

If you are new to this, then I would have to agree with Scott and say don't bother unless your TR is under 1.6:1 because the small amount that is there will not be that obvious. And if you intend to move the A-Lens for 16:9, you probably don't want a curved screen at all if you watch heaps of 16:9 program.

I have a client with an MK4 and a TR of just 1.4:1. I am struggling to convince him to curve his screen and the interesting part is that for a movie (motion image) you generally don't see it. You will see it for test patterns, but we don't generally watch test patterns.

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post #38 of 48 Old 04-08-2012, 11:37 AM
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Mark, I have a question for you. I have a scope setup with a throw ratio of about 2.2:1 so pincushion is very slight. With a small crosshatch pattern I can see the slight expansion of the squares are the edges of the screen. This is exactly as one would expect with a flat screen. Now here is my question. I can notice the slight expansion at the horizontal screen edges with movies shot in Super 35 format while those shot in Panavision or with an anamorphic lens do not show the same distortion. I figure the distortions of the camera lenses must cancel out the distortion of the anamorphic lens on the projector. I have watched many movies and aside from the lens flare I can tell the difference from Super 35 vs. Panavision. Do you have any thoughts on this observation?
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post #39 of 48 Old 04-08-2012, 05:47 PM
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Quote:
Originally Posted by CRGINC View Post

Mark, I have a question for you. I have a scope setup with a throw ratio of about 2.2:1 so pincushion is very slight. With a small crosshatch pattern I can see the slight expansion of the squares are the edges of the screen. This is exactly as one would expect with a flat screen. Now here is my question. I can notice the slight expansion at the horizontal screen edges with movies shot in Super 35 format while those shot in Panavision or with an anamorphic lens do not show the same distortion. I figure the distortions of the camera lenses must cancel out the distortion of the anamorphic lens on the projector. I have watched many movies and aside from the lens flare I can tell the difference from Super 35 vs. Panavision. Do you have any thoughts on this observation?

Hope this makes sense:

I believe your referring to "anamorphic mumps" (as Tony would call them) where the grid distortion of one anamorphic lens during capture would not be fully offset by another for projection. I have seen this on my own system for older films (pre 80's) but have not noticed it for more recent films. "Mumps" will appear at the edges of a panned image which may make the object of focus appear fatter at the edges than it did in the centre. Does that make sense?

These "mumps" should only occur for anamorphic capture. If your seeing this on other material, then it is grid distortion of the A-Lens you are using and curving the screen may be what is needed.

Newton's 3rd law: If the same anamorphic lens was used for both capture and projection like when I demo my "anamorphic bees" video, there will be no 'mumps' or grid distortion what so ever on a curved screen and maybe a small amount of GD on a flat screen pending the TR.

However, if you used an ISCO for capture and one of my MK5 of projection, you may see these "mumps" because the optics are now different. My lens does use "multi-aspheric" radii. Combine that with the curved screen, and I have zero grid distortion for playback, but I can not control how the image was captured when screening BD or DVD. Lucky there have been many radical improvements to capture lenses over the years.

Curving the screen is mainly for pincushion distortion correction, but it also assists with grid distortion correction. My lens came under allot criticism a while back and when I posted screen images from my curved screen. I did so simply because pictures are worth a 1000 words, and so the so called experts chimed in (only one was qualified, but had another agenda), and before I could respond, the threads became heated and were locked. One image showed that the curved screen appeared to optically compress the image (a test pattern), resulting in what looked like circles being compressed to ovals. What was not mentioned back then was that when when looking at the curved screen in person that the screen is actually a 3D space and the circles are indeed round. When capturing them with a 2D camera, the effects of the curve make the circles appear slightly squeezed because it loses that 3rd dimension of depth. This then lead those making inaccurate statements suggesting my lens used bad optics. And I was not given the opportunity to respond and nothing is further from the truth, hence why I have taken this opportunity to do so now.

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post #40 of 48 Old 04-09-2012, 07:46 AM
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Quote:
Originally Posted by CRGINC View Post

Mark, I have a question for you. I have a scope setup with a throw ratio of about 2.2:1 so pincushion is very slight. With a small crosshatch pattern I can see the slight expansion of the squares are the edges of the screen. This is exactly as one would expect with a flat screen. Now here is my question. I can notice the slight expansion at the horizontal screen edges with movies shot in Super 35 format while those shot in Panavision or with an anamorphic lens do not show the same distortion. I figure the distortions of the camera lenses must cancel out the distortion of the anamorphic lens on the projector. I have watched many movies and aside from the lens flare I can tell the difference from Super 35 vs. Panavision. Do you have any thoughts on this observation?

That is something of a mystery. The "mumps" as Mark described are an artifact of very early anamorphic cinematography. It is very noticable on The Robe, for instance. Two decades ago when I was approaching my first anamorphic gig, I went to Panavision and met with the VP for the optical department to get my education on anamorphics. It was a fascinating field trip.

Panavision came to prominance due to their successful elimination of "the anamorphic mumps." The mumps only became a distraction when the subject and therefore the focus distance on the lens came into the range inside about 10'. Of course, this was for closeups when we would easily notice this artifact.

Panavision overcame this by incorporating an additional anamorphic element that was variable and was applied progressively as the focus was adjusted within the mumps range. This additional bit of optics and mechanics was very physically noticable on all Auto Panatar lenses as a noticable extrusion to the side of the lens barrel in most series prime lenses (C-series and E-series still in use today). Most Panavision anamorphic zoom lenses did not use this arrangement, instead using a cylindical rear element. I don't recall the mumps issue with them. That's surprising, because we often used them...so maybe there was something else going on in the zooms of which I was not aware. That said, zooms were typically used for shots well outside the mumps range.

You can read a fascinating short history of Panavision, including this specific subject of anamorphic mumps here: http://www.btlnews.com/gear/panavisi...ersaryhistory/

So, if you're seeing anamorphic mumps, it's not films shot with Panavision 35...unless it is caused by a projection anomoly of some sort.

Quote:
Originally Posted by GetGray View Post

We didn't talk about the personal preference factor. Some people like the look of the curved screen in the room, some don't care for it.

And that would seem to be a rather big reason for choosing a curved screen. Visual impact, that feeling of the screen "getting its arms around you," is powerful. One peculiar thing I seem to find with curved screens, though, is that they can be too small and that feeling of the screen overtaking you is not there...especially for the widest seats in the primary row. It seems to need to be out there at 45 degrees HVA or so to get that. What is your perception on this, guys?
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post #41 of 48 Old 04-09-2012, 12:56 PM
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Mark and Cam Man, No mumps are in the center of the screen. The very small amount of expansion is toward the horizontal edge of the screen just like when I use the VP to project a grid pattern so it is my lens distortion is because of my flat screen. I understand this resulting distortion goes unnoticed unless I look for it but on Panavision filmed movie it appears to disappear vs. Super 35 movies which don't use an anamorphic lens to achieve cinemascope. Does even the "new Panavision lens" have some compression at its edges that the lens in my projector compensates for? Mark I know you shot some cinemascope movies yourself just to see if a true anamorphic BD would show better resolution. Any distortion in your lens in the photography would be compensated for in the same lens during projection would be totally compensated for. In a true anamorphic capture and anamorphic projection lens errors will either totally or partially cancel each other while if the capture is non-anamorphic as in Super 35, there is only one non-linear lens in the projection path. That is the only explanation that I can think of that would cause what I see. Just curious as to why I notice this.
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post #42 of 48 Old 04-09-2012, 03:07 PM
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Quote:
Originally Posted by CRGINC View Post

Mark and Cam Man, No mumps are in the center of the screen. The very small amount of expansion is toward the horizontal edge of the screen just like when I use the VP to project a grid pattern so it is my lens distortion is because of my flat screen. I understand this resulting distortion goes unnoticed unless I look for it but on Panavision filmed movie it appears to disappear vs. Super 35 movies which don't use an anamorphic lens to achieve cinemascope. Does even the "new Panavision lens" have some compression at its edges that the lens in my projector compensates for? Mark I know you shot some cinemascope movies yourself just to see if a true anamorphic BD would show better resolution. Any distortion in your lens in the photography would be compensated for in the same lens during projection would be totally compensated for. In a true anamorphic capture and anamorphic projection lens errors will either totally or partially cancel each other while if the capture is non-anamorphic as in Super 35, there is only one non-linear lens in the projection path. That is the only explanation that I can think of that would cause what I see. Just curious as to why I notice this.

Hi there. Still a mystery to me. The amount of optical squeeze from a professional anamorphic camera lens is going to be consistent across the entire screen. That said, focal lengths wider than about 35mm in anamorphic will begin to have a fair amount of geometric distortion at the sides. Because everything occurs in an elipse rather than a circle, these distortions will be most noticable at each side. Focus at the sides can also start to get rather wanky with such focal lengths at wider stops.

What you're describing is rather strange; kinda like a progressive stretch done electronically. That you only see it on spherically shot 2.35 material is really weird.
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post #43 of 48 Old 04-09-2012, 03:51 PM
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Originally Posted by Cam Man View Post

And that would seem to be a rather big reason for choosing a curved screen. Visual impact, that feeling of the screen "getting its arms around you," is powerful. One peculiar thing I seem to find with curved screens, though, is that they can be too small and that feeling of the screen overtaking you is not there...especially for the widest seats in the primary row. It seems to need to be out there at 45 degrees HVA or so to get that. What is your perception on this, guys?

My screen is a little larger than my (4) seat width, a little larger. "Feels" good. Not too small, although I would not mind another foot or 2
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post #44 of 48 Old 04-09-2012, 05:11 PM
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Originally Posted by GetGray View Post

My screen is a little larger than my (4) seat width, a little larger. "Feels" good. Not too small, although I would not mind another foot or 2

Great minds. That's my scenario, as well. I use the two outside seats of my four seat row as a reference for this. I'd like the two outside seats to have to "look" to their left or right a bit to the nearest edge of the screen.
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post #45 of 48 Old 04-09-2012, 06:20 PM
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Originally Posted by Cam Man View Post


And that would seem to be a rather big reason for choosing a curved screen. Visual impact, that feeling of the screen "getting its arms around you," is powerful. One peculiar thing I seem to find with curved screens, though, is that they can be too small and that feeling of the screen overtaking you is not there...especially for the widest seats in the primary row. It seems to need to be out there at 45 degrees HVA or so to get that. What is your perception on this, guys?

My only (limited) perception is that I've never seen a curved screen, commercial or otherwise, that I liked.

I get the reason for them. But I always found myself somehow aware of the non-flat nature of the screen, aware of the curvature, and for me it felt more artificial. I find a perfectly flat surface with a great image more natural and believable, all things considered.
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post #46 of 48 Old 04-09-2012, 06:32 PM
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Don't like IMAX? My IMAX has a curved screen.

Anyway, when looking at the image you can't see the curve. Only at the edges do you get a visual cue.
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post #47 of 48 Old 04-10-2012, 08:59 AM
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Originally Posted by R Harkness View Post

My only (limited) perception is that I've never seen a curved screen, commercial or otherwise, that I liked.

I get the reason for them. But I always found myself somehow aware of the non-flat nature of the screen, aware of the curvature, and for me it felt more artificial. I find a perfectly flat surface with a great image more natural and believable, all things considered.

I heard someone on the forum put it this way...that curved was "immersive" while flat was like "looking through a window" into the world of the movie. Both are totally valid since they evoke a feeling that is desirable and effective. It's just a matter of which evokes the feeling in you.
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post #48 of 48 Old 05-13-2012, 01:16 PM
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Originally Posted by blastermaster View Post

Counterbond,

AKAIK, only the 5010/6010's have a mode that will accommodate an anamorphic lens (ie. vertical stretch mode). You should check into that before you move on. If you can afford it and can return it, I'd suggest getting the 5010 which I'm pretty sure has anamorphic stretch and definitely has lens shift.

I have an Optoma HD3300 which has anamorphic stretch mode and it works in 3D as well (pretty amazing). That said, I think the image I have is too large for 3D. It's fine for 2D but in 3D some of the high speed scenes get pretty damned nauseating. Best overall 3D experience I've ever had, though, bar none. Christmas Carol 3D with Jim Carrey one of the most amazing things I've seen in my home theater.

I have a 3010 And absolutely love what it can deliver for under $1400...recently we discovered a hidden gem where by accessing some service menu we are able to turn on one of the key features of 5010 which is pixel alignment. You can't ask for more oh well, now I was wondering if I can use it for an anamorphic lense somehow...I know you said 3010 doesn't support vertical stretch mode, but can I purchase a bluray player that can do the same for me ?
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