See the discussions at http://people.smu.edu/rmonagha/mf/mfbest.html
and http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=000WNn
Considering diffraction, the best aperture is the widest.
Considering lens faults, the best aperture will vary with the design and
construction, but usually is f/5.6 to f/11.
See the tests at http://members.aol.com/olympusom/lenstests/default.htm
tOM
On Saturday, August 24, 2002 at 12:01, Keith Quarles
<olympus@xxxxxxxxxxxxxxx>
wrote re "[OM] Diffraction limitations?" saying:
>
> >Ok, I keep hearing about how smaller apertures give greater depth of
> >field and apparant sharpness to a point, and then the increase is
> >nullified by a rise in diffraction.
> >
> >My question is this: at what point does this happen? I'm not looking for
> > the mathematical equation to figure it out, I just want to know for a
> >given 35mm lens of a given length, say 25, 50, 100, 200, or 300, what
> >would be the best aperture for sharpness.
> >
> >Thanks, Steve Goss, Dallas Tx usa
>
> The rule of thumb I've always heard was 4mm. From this point and smaller,
> expect diffraction effects. Just divide the lens focal length by the f-stop
> to get the aperture diameter.
>
> Keith Quarles
> kquarles@xxxxxxx
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