In article <55f0qk$m3p@solaris.cc.vt.edu>, wachira@birchh.ee.vt.edu says...
[the original address had been deleted, so e-mail
response to the original poster is difficult...]
>>I have a question concerning Nikon lenses. I have a Nikon FM with
>>a Vivitar zoom lens which has 1/2 stop indents in the aperture ring.
>>I recently got an FM-2n with a 50mm f1.8 and a 70-210 f4-f5.6. The
>>Nikkor lenses apertures are indented in full stops. Sometimes, when
>>I'm just metering different situations, I find that the correct
>>exposure falls between f-stops. Is it ok to use the camera with the
>>aperture set between indents?

Yes, Nikon lens apertures are continuously variable (press the DOF
lever, and look into the front of the lens while moving the aperture
ring, to see that this is true), which is why I dislike 1/2 stop detents.
Hope This Helps