LH
> i've heard about that argument (light defraction) in print, physics class
> and so on but it just isn't true in real life (photographically speaking).
> in my darkroom i've experimented with all the different aperature size as
> well as my lenses for my camera and i have to conclued emphatically that
> the smaller the aperature the sharper the image. i have not found the
> "middle of the road" setting that so many people talk about (i.e. f/8,
> f/11) to offer the sharpest image.
>
> someone will have to come up with concrete proof that defractioin plays a
> role in f/22 setting. also consider that some of the best landscape photos
> are from the "pin-hole" lightbox users.
>
> i don't know. i toss my hands up on this.
[...quotes of other posts deleted...]
Assuming that you are using 35mm format, and that your lenses are of
high quality, you should easily be able to see a decline in both resolution
and contrast in the image as you move from f11 to f22 in the taking lens...
(assuming slides viewed with a high-quality 4-5X magnifier, or well-made
5x7 or larger prints - and sharp film). If you are using medium format, you
will move this effect down about a stop - and with 4x5, yet another stop or
two (noticeable decline may not occur until about f32-45). If you are using
a zoom, you may well find that it continues to improve as you stop down
to f22, but this is more an arguement for using a better lens than a smaller
stop, I think... While f22 can provide completely adequate image quality in
the 35mm format (and it will increase DOF), those who care about "snap"
and good rendering of fine image detail may choose to use fine lenses at
f5.6-f11 (and some of the best short teles can provide excellent sharpness
by f2.8-4, allowing shallow DOF with high sharpness). Those who do not
care about optimum sharpness, or who would prefer more universal
DOF, may well choose to use small stops.
Hope This Helps.
David Ruether - http://www.fcinet.com/ruether