In article <5483i9$iif@laplaza.org>, studio52@laplaza.org says...

> Are the PC lenses ie: Nikkor 28mm 3.5, Leica 28mm 2.8 or others
> sharp, excellent, and how about when there fully shifted do they fall
> off on sharpness at center to edge?

Not an easy question to answer, since it has several different answers,
depending on particular lenses and how they are used. One advantage of
PC lenses is that they counter the unfortunate fact that many 35mm-format
wide angles do not really cover the format at wider apertures (they are
not sharp in the corners, and sometimes not even at the edges at wide apertures). If you like uniformly reproduced textures across the frame
and to the corners, with even illumination at wider apertures, PC's are
often the only way to go. Most of the Nikkor PC's are quite sharp to the
corners wide open when unshifted, sharp to the upper corners by about
f8-11 when fully shifted vertically on a horizontally oriented frame, and
almost sharp in the upper corners at f22 when fully shifted vertically
on a vertically oriented frame (this is shift beyond the design limits,
but there is no vignette if a thin-rimmed filter and no shade is used).
My favorite PC's in terms of image quality are the earlier Nikkor
28mm f4 PC and the most recent version of the 35mm f2.8 PC (which is a
REALLY excellent 35mm lens).
Hope This Helps