Re: Slit width - Distance to fim plane

[Andrew Davidhazy <ANDPPH@xxxxxxxxxxxxxxxxxx>]

> Does any one have any thoughts or answers to how wide a slit should be and
> how far it should be from the film plane? I have been building a camera with
> a 24mm Nikon lens using 120 film stock and a 1mm slit placed 10mm from the
> film plane.

The farther the more astigmatism (I think that is what it is) will destroy 
image sharpness and the more the aperture settings on the lens will be
inaccurate especially at large apertures. The closer the more accurate the
aperture settings and the sharper the image but also the more that "banding"
will rear its ugly head.

> I still can't get a really sharp image even at f16. The film transports
> around a drum omega style and has an image of 149.5mm for 360 degrees.
> Also, I know that the rule says 2 x focal length x Pi or 150.796mm but is
> 149.5mm close enough?

You'll never notice it. In my opinion ... and personal experience.

regards,

Andy  o o  0 0 o . o  Davidhazy, Imaging and Photo Tech
       \/\/\/\/\/\/          http://www.rit.edu/~andpph
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