Anamorphic projection but NOT curved screen?

[DucatiR]

During my reading over the last several months I have somehow come under the impression that anamorphic projection required a curved screen for pincushion projection. In a different thread I learned from Prof. that this may not be the case. I am creating this separate thread for my specific circumstance. Do I need a curved screen?

- BenQ W5000 projector (not purchased yet), ceiling mounted about 15-16' from screen.
- Acoustically transparent screen will be maximum 100" width, 1.2 gain (Seymour's new XD material).
- anamorphic lens

I have presumed a curved screen was required. But in a different thread (link below) Prof. had this to say:

Prof. wrote:

The W5000 has a high TR., when set to zero zoom and from the projection distance and image size that you're looking at...
This means that you will have minimum pin cushion and that you won't need to have a curved screen..
I would just use a flat screen..

I don't intend to question Prof., but I've had this curve requirement in my head so long I feel I need to ask the question again just to make sure before I proceed with construction of the screen wall.

My construction build thread:
http://www.hometheatershack.com/foru...questions.html


Bruce Fisher's thread on anamorph & screen
http://www.hometheatershack.com/foru...tml#post168814

[Prof.]

DucatiR,

Have you come to a decision on your screen yet?

I may be able to throw some light! on your dilemma..

I've recently installed a new projector and made a bigger CIH screen..
I had some concerns with the new set up, as to whether I would need to go to a curved screen or not..
The problem was that the new projector needed to be closer than previous..even with the bigger screen..
This reduced my TR to a shade under 1.7..
Also the new screen is 8" wider, which makes for a very wide angle of projection..and I felt that the pinchusion might be excessive..

I decided to make a flat screen and hope for the best..If it didn't turn out suitable then I would have to make a curved screen..

The end result surprised me..Not only was the pincushion no more noticeable than previous, but the image sharpness right to the very edges was even better..even with that wide projection angle!!
Probably the better quality projector did have something to do with it, but it did show me that I didn't need a curved screen..

There is another disadvantage to using a curved screen that has some gain..
You do get a smaller viewing cone which will drop some light output when viewing on an angle..

But it does come down to personal preference..Some people use curved screens just for the effect, when they don't really need to have one..

[DucatiR]

Prof.,
Thanks much for that additional information. I've been monitoring the thread and concluded today, after 30+ views and no bites, that "Prof. has spoken! Silence = consensus!!"

I've also seen a grid screen shot of the MK3 from the Australian sales outlet.
http://www.anamorphiclens.com.au/
See the second thumbnail in the image grid near the bottom of the page - the test pattern. The pincushion effect can be seen in the lower and upper center edge of the screen but barely. Between your feedback, Chris' at Seymour and the sales people at ProjectorScreens.com I have concluded I will go with a flat screen.

I'm now just waiting for Seymour to release the specs/prices on their new fixed frame products to determine if I go out of the box kit or DIY frame + Seymour fabric.

Thank you again Prof. You've saved me considerable design and construction headaches!

DucatiR

[Prof.]

DucatiR wrote:

Prof.,
Thanks much for that additional information. I've been monitoring the thread and concluded today, after 30+ views and no bites, that "Prof. has spoken! Silence = consensus!!"

I'm not the expert..Mark is, but I guess he's very busy filling orders for the new lens..

Thank you again Prof. You've saved me considerable design and construction headaches!

DucatiR

Happy to help...

[Bruce Fisher]

Sorry - been busy working on my theater and hadn't checked in for a week or so.

I exchanged emails with Mark (Aussiemorphic) about this topic. His response (paraphrased) is "flat screens generally work fine and you shouldn't need a curved screen. However, curved screens look really cool! That said, most people don't see a pincushion effect and it should be fine for you. I'd suggest starting with flat and upgrade to curved later if you really find you need it".