In article <19970326080501.DAA18842@ladder01.news.aol.com>, hmorhm@aol.com says...

>I too was taught that, given a choice, I should set the aperature two or
>three stops down from wide open to get the best overall performance.
>
>My question is: if my preference is for maximizing the depth of field
>in the my compositions, should I be looking for a wide angle lens
>whose maximum aperature is fairly slow, say f6.3 instead of f3.5?
>Then when I shoot at f16 or f22 can I expect the slower lens to
>perform better than a faster lens? Or is all the extra effort the lens
>designers put into a fast lenses going to have some benefit when
>I am stopped down five or even six stops? My inclination is to go
>with a slower lens, but it may be a hangover from the way I was
>taught.

You may want to go back and read my earlier post in this thread....
I keep hoping that the inaccurate old saw about "2-stops down..."
will disappear, but it doesn't... (it arose, I think, due to a
coincidence that most lenses of an era long ago were about the same
speed, and the optimum aperture (which is nearly the same in most
good lenses within a format [and there was not much range in available
formats when this currently incorrect rule-of-thumb appeared]) was
about 2-3 stops away from that common maximum aperture. But now we
have f1, 1.2, 1.4, 1.7/8/9, 2 lenses, and these are clearly not
optimal at f2-4... Also, many a good wide-angle, even if f2 or f2.8,
doesn't reach optimum performance overall until well stopped-down
(maybe f11-16). And virtually all good lenses for a given format peak
in the center at virtually the same stop (regardless of FL or maximum
aperture), after which diffraction limits performance (making almost
all good lenses virtually identical in center performance at smaller
stops). So, let's put the old saw to rest, huh? ;-)
Hope This Helps