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Looking to go hunt down a Nikon 105mm f2.8 Micro AI-S (manual focus) lens soon, but I got a silly question.
The current 105mm f2.8 Micro VR autofocus lens stops down in f-stop at minimum focus due to 2.8 being extremely shallow at this point.
Does anybody know if the old 105mm f2.8 Micro AI-S does the same thing or can the aperture actually be 2.8 at minimum focus?
I've tried google, but could not find an answer -.-;;

How could I test that for you? Using the DOF preview on the FE2 doesn't show any stopping down against a ruler with that lens...you can see the DOF increase from f2.8 to 4.

Check the TTL light meter for a change in exposure?

That or, I was wondering if the lens physically stops you from focusing to minimum while the aperture is 2.8.

Never tried the lens in question, but generally the aperture blades do not change at all. It's the extension of the lens barrel during close focusing that changes the ratio between focal length/lens diameter (it's f/2.8, not f*2.8 ).

I've seen the Tamron and Tokina macro lenses (of around the 100mm length) register a different f-stop to the body as focusing gets closer. My Sigma 105mm f/2.8 does not. I should check that on my FE2.

The Nikon 105 mm VR does register a slightly higher aperture depending on the closest distance of the subject

+1

Solved.
The 105mm 2.8 AI-S (Manual Focus) Micro lens will retain aperture of 2.8 at minimum unlike its digital successor.

Source: I own the 105mm f2.8 AI-S lens now.