Kodak has started shipping a line of large, square format image sensors that have a diagonal of around 50 mm. There are two chips initially. The KAF09000 is 3k x 3k with 12 micron pixels and the KAF16803 is 4k x 4k with 9 micron pixels. This is a challenge for most imaging systems to handle. One of the first questions that comes up is filter size. A rough idea of the needed filter size can be obtained from the following formula:

A = 50 mm + d/F where

A is the clear aperture needed to pass the light cone
d is the distance from the image chip to the aperture
F is the F ratio of the system

For example, assume an F/9 system where the imaging chip is 90 mm from the limiting aperture. Then A = 50 + 90/9 or 60 mm. Now assume the aperture is only 27 mm from the aperture. Here A = 50 + 27/9 or 53 mm. Lastly, assume a 27 mm separation but with an F/3 system. Here A = 50 + 27/3 or 59 mm. Thus you can see that both the distance between the imaging chip and the aperture (or filter) and the F ratio of the system will affect the amount of vignetting.

Note that this discussion does not include diffraction effects. In fact, if the resultant aperture "clipping" is not too severe, you may be able to "flat out" the vignetting, at least to a degree.

Clearly some experimentation is needed for each system but this should give you some ideas on the scale of the problem.

This message has been edited. Last edited by: John Smith,