Paul writes:
======================
I think that you're ignoring part of the reason (in addition to grain)
that modern film cameras stopped getting smaller... [snip]
lose sharpness above about f11 because of diffraction effects... [snip]
With smaller CCD pixels the problem would only get worse.
======================
I don't follow this. with a smaller format image, depth of field is
greater, so you can use a bigger f-stop while maintaining a given level of
depth of field. interestingly enough, this will translate into exactly
the same size physical diaphragm diameter to maintain DOF, but with a
shorter focal length, the diaphragm is closer to the film/CCD so the light
has less time to spread out after passing through the aperture, hence a
smaller diffraction effect.
Diffraction gets worse as format gets larger, not smaller, which is why
larger format cameras have tilt movements.
Also interesting is that you enlarge larger format less, and if you compare
format sizes with a plan to make fixed size enlargements while maintaining
depth of field constant across the prints, then diffraction differences are
irrelevant. the larger format has more diffraction effect, but it is
exactly enlarged less by an amount to make the diffraction effect on the
print be the same as the image from the smaller format.
================================
CCD's have been around long enough that the minimum pixel size is also not
going to get that much smaller while maintaining ASA rating and noise margins,
================================
I can't think of any computer or digital technology where this type of
reasoning applies.
==================
so if you want bigger (pixel count) arrays they're going to have to be
bigger physically.
==================
or be manufactured using a yet to be developed technology that has
smaller pixels.
Joseph
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