Not only is lens quality a limiting factor to how much information a CCD of
given size can extract, but so are diffraction effects. As we know, lens
resolution is often diffraction limited past f5.6 on our wide angle 35mm
camera lenses. I think (if you know for certain, correct me!) that like
depth of field, diffraction effects are a function of the aperture's
absolute size, so an aperture that would be f5.6 on a 35mm lens would be
about f2.8 on the typical digital camera lens. This means that digital
cameras with the usual sensor size are performing pretty close to the
diffraction limit when they are wide open, and as you stop down you may
actually be losing resolution pretty rapidly. f11 might on my C3030 may be
like f45 (depth of field and diffraction-wise) on my OM.
That may be why you don't see higher f numbers on most digital cameras, and
why a move to a larger physical sensor size may be inevitable for higher
quality.
Please correct me if I am in error here, I didn't pay much attention to
optics in my physics courses - to my detriment!
Chip Stratton
> I've
> also noticed that the minimum aperture opening is around f11, is this
> due to the need to have a wide enough opening to maintain this near
> perpendicular angle of incidence to the sensor? For example, even a
> pinhole lens will be blurry with an imaging device that has pixel
> depth. Could someone make an optical adapter to parallel up light rays,
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