In article <33C1C69A.2198@worldnet.att.net>, cfscnw@worldnet.att.net says...

>The Nikon F4 instruction booklet says the 35mm f3.5 PC lens (the old
>early 60's lens) cannot be used on the F4, without explaining why. Does
>anyone know why?
>I know the PC lens is non AI, but most non AI lenses can be used on the
>F4. The PC lens works fine on a F3.

I am guessing that the clearance between the old shift lens and/or
the shift knob is not sufficient to clear the prism front on the F4
with some movements, and/or the bayonette may interfer with electrical
contacts or something else inside the camera (how's that for equivocating, huh...? ;-).
Hope This Helps
(David Ruether - http://www.fcinet.com/ruether )