Anamorphic Prism vs Spherical lens question - AVS Forum
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Old 05-20-2011, 05:23 AM - Thread Starter
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I apologise if this seems an overly simple question, I see alot of expert opinion on this forum and I dont mean to waste anyone's time. I have been designing systems based around Anamorphic projection for a little while now but have recently be told by one of my suppliers of high end screens that curved screens are for spherical lenses because they get pincushioning whereas prism lenses are for flat screens. This sounds odd to me, I had always thought that the pincushion was directly related to your throw distance - not ur lens type.
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Old 05-20-2011, 08:41 AM
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Both have pincushions. To reduce/avoid it, you will need to curve the screen. Although, curving the screen is not a requirement. Most of us did not curve the screen and just masked off the pincushion part.

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Old 05-22-2011, 07:13 AM
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Quote:
Originally Posted by pjfhifi View Post

This sounds odd to me, I had always thought that the pincushion was directly related to your throw distance - not ur lens type.

It sounds odd because it is wrong. All anamorphic lenses produce pincushion and the only way to correct this is to curve the screen. It is true that you don't need to curve the screen and that you can mask off (typically apply a small amount of zoom) to hide this effect.

The term "sperical" is also not correct. These types of lenses are "cylindrical".

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