Hi--

I've had a look at your web site, and some of your usenet posts, and
found it very interesting. In particular, you say that the '2 stops
down from maximum aperture' rule of thumb is rubbish, you subscribe to
the 'f8 is best' maxim. I've got a few lenses and I wish I knew what is
the best aperture to use when light / dof is not the determining factor.
For example, I have a Kiron 28mm f2 (I use it on my Olympus Om4). If
you check out

http//members.aol.com/olympusom/lenstests/default.htm

you can see that it apparently performs best about 2/3 stops from max
aperture! f4 and f5.6. OK, it's still fine at f8 but it does seem that
some lenses do perform best at apertures a little either side of f8 -
the above site has some very detailed tests. Just an observation -)

andy -)

I say that for most good lenses, peak resolution occurs
between f5.6 and f8 in the center... This does not preclude
the exception, and an early version of the 50mm f1.4 Nikkor
peaked at f4 in the center (but far from that in the corners).
Also, resolution often varies considerably with focus distance,
and some lenses that peak near infinity not far from f4 are quite
poor at f4 near minimum focus distance, especially at the
edges/corners. Your exception is an interesting one that I would
like to try. Also, high-resolution lenses are often low-contrast
(this is the design trade-off, alas...), which does not make for
a good sharpness compromise - a "snappy" lens of lower resolution
often looks better in images...