I know of only one projector that can display 2.35:1 nativelythe projectiondesign Optix SuperWide 235 (seen here)which was announced at CEDIA last year. However, I don't know if it's available yet, and even if it is, the price was announced to be in the $40,000 range.
What you want is known as "constant-height projection," and there are a couple of ways to accomplish it with a 16:9 projector. One method is to place an extra lens in front of the projector's primary lens. This so-called "anamorphic" lens optically stretches the image horizontally, which means the projector (or an outboard video processor) must electronically stretch or scale the image vertically in order to fill a 2.35:1 screen. Anamorphic lenses cost at least $5000, and in some cases a lot more.
The projectiondesign Optix 235 does not require an anamorphic lens, but it does scale a 2.35:1 movie on Blu-ray from 1920x817 to 2560x1080, which could introduce scaling artifacts.
There are two ways to mount the anamorphic lensin a fixed frame or a motorized sled. If the lens is mounted in a fixed frame, the projector's processor must be able to process a 16:9 image so it fills the height of the screen, which means the image is scaled horizontally with black bars on the sides. A motorized sled moves the lens into and out of the light path depending on whether the image is 2.35:1 or 16:9, which avoids the extra horizontal scaling. Of course, a motorized sled is quite expensive in and of itself.
A third, less-expensive option is to find a projector with "lens memories." Such a projector can store different zoom and focus settings that fill the height of the screen with a 16:9 or 2.35:1 image, and you simply select the memory that corresponds to the image you are watching. In this case, no scaling is needed, but the black letterbox bars of a 2.35:1 movie are zoomed outside the screen area. Very few projectors offer lens memoriesone is the Panasonic PT-AE4000U, an LCD model that lists for $2500.
There is considerable debate about the pros and cons of anamorphic lenses. Proponents argue that this approach uses all the pixels provided by the projector, while skeptics point out that vertically scaling the image can degrade the picture quality, as can the horizontal scaling for 16:9 images with a fixed anamorphic lens. Also, the more glass the light must pass through, the more chance for optical distortionin fact, curved screens are often used with anamorphic setups to compensate for a particular type of optical distortion. (Note that the projectiondesign Optix 235 does not require an anamorphic lens, but it does scale a 2.35:1 movie on Blu-ray from 1920x817 to 2560x1080, which could introduce scaling artifacts.)
A projector with lens memories suffers from none of these problems, but the vertical resolution of a 2.35:1 movie is only 817 pixels.
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