In article <4i1n3j$2ai@ampersand.jpl.nasa.gov>, Donald.D.Farra@jpl.nasa.gov says...
>If I wanted to run the same comparison test what would I have to do? >The reason I asked is it appears the set of test pictures were taken at
>different times and locations. Also your method of comparison was not
>clear, visual or measured by test patterns.
See answer to Gary Toop's post, above for the beginnings of some of the answers to your questions. (It has been months, but that lens checking article IS being slowly worked on....)
>I am currently planning on running a series of comparison tests on the
>Leica 35/1.4 asph to Canon and Nikon lenses both prime and zooms of >equal focal lenght. [much deleted]
Good luck! I would simplify your technique/materials - you will still see differences with even the simplest methods, and with any film.
(I have it down to 6 frames for checking a familiar prime lens for
construction defects and center-corner performance at relevant
apertures - though it takes more to check an unfamiliar lens or a zoom.)
>My testing goals are simple: determine the attributes of a particular
>lens with a fixed set of film & lighting conditions and make the tests
>repeatable such that anyone given the same equipment can repeat the >tests and come to the same conclusions. The problem is the closer I >get to removing the human component from the evaluation process the >less likely the test will be repeatable by anyone using the same
>camera equipment.
>Any suggestions? Please post them.
>Don
Lots, but that would mean I finished the article! ;-) In designing
tests, I would suggest remembering that lenses vary in performance
with distance at least slightly (some, a lot!), flat targets are
nearly impossible to focus accurately, almost any film will work
(contrary to popular opinion), some wide-angles will show differences
in corner performance with color vs. B & W film, some lenses have
field curvature, and most (good) lenses vary most in quality at the widest apertures and at the edges/corners. That's after eliminating
the lenses that are unacceptable due to flare, cost, size, weight, distortion, condition, or any other characteristic that is bothersome
to you.
Hope This Helps