In article <5s8tqe$41a@mozo.cc.purdue.edu>, garyjaz@omni.cc.purdue.edu says...

>Let's say you have a 28-80 3.5-5.6 lense. Ideally, is there a
>focal distance that you would want to shoot at, like say 50mm?
>
>And for clarity in your subject, would it be best to shoot with
>the f-stop at 4.5?

With zooms, there may be an optimal focal length(s), an optimal
focus distance(s), and an optimal aperture(s) (and they may be
interactive, greatly complicating the issue...). In general,
experience with your lens would be necessary to tell about where
it is optimal - but I am, uh, "fairly" sure that one of the optimal
conditions is not an aperture of f4.5...;-) As a guess (with this
example), best performance may be in the near-infinity focus range,
stopped down to f11 or so, and maybe around 40mm... (though this
could easily be quite wrong! ;-).
Hope This Helps
(David Ruether - http://www.fcinet.com/ruether )