Do AI lenses have maximum aperture index pin?

[Michael L. Pipkin, M.D.]

There is a pin or lug at 7 o'clock on the mount of all AI-S lenses (looking
at the lens from behind) which Nikon calls the maximum aperture indexing
pin.  Only the FA and F4 (I believe) use this pin to obtain the lens'
maximum aperture.  However, my AI 55mm Micro has this pin and I am wondering
when it appeared in production.  Any manual focus AI (not AI-S) lens owners
who would be willing to examine their lenses for presence of this pin,
please tell me whether your lens has it, along with serial # or year of
manufacture and focal length/speed.  I will report back to the list as to
how early Nikon started preparing to offer Matrix metering, because that is
what the maximum aperture indexing pin is for I believe.

Michael

FA meter modes

[Michael L. Pipkin, M.D.]

"Daniel I. Applebaum" [EMAIL PROTECTED] wrote:

The FA also provides matrix metering with non-CPU lenses, but only
with AI-S lenses, not AI or AI modified.

The FA (like the F4) DOES matrix meter true AI lenses if they have the
maximum aperture lug.  I don't know whether all do.  AI'd and non-Nikon AI
lenses do not have this lug (look at the back of the lens: the maximum
aperture lug is the stubby protrusion at about 7 o'clock).  Matrix metering
requires that the camera know the actual f/ratio of the lens so it can
estimate the brightness of the scene.  All AF Nikons except F4 obtain the
maximum aperture electronically only.

MLP