Nikkormat Ft2 vs Ft3, what is the difference, they look identical...

Well that's reassuring; Thanks!

In fact AI (auto indexing) is really no indexing as the camera doesn't know the max and min aperture of the lens like the pre AI camera does.

Chan Tran said:

In fact AI (auto indexing) is really no indexing as the camera doesn't know the max and min aperture of the lens like the pre AI camera does.

Click to expand...

It does, there's the tab on the aperture ring that tells the meter what aperture is selected, and there's a secondary stationary tab that indicates what the maximum aperture of the lens is. Were the maximum aperture not communicated, you would have to do stop down metering.

Minimum aperture is irrelevant unless it's the selected aperture for exposure, the Non-AI lenses have you do the shuffle to the minimum aperture, because this forces the light meter to reset the previous maximum aperture.

Hunter_Compton said:

It does, there's the tab on the aperture ring that tells the meter what aperture is selected, and there's a secondary stationary tab that indicates what the maximum aperture of the lens is. Were the maximum aperture not communicated, you would have to do stop down metering.

Minimum aperture is irrelevant unless it's the selected aperture for exposure, the Non-AI lenses have you do the shuffle to the minimum aperture, because this forces the light meter to reset the previous maximum aperture.

Click to expand...

The AI coupling only tell the camera how many stop the lens will be stopped down from maximum but it doesn't tell the camera what's the maximum aperture is. This is the reason why the Nikon F5 doesn't do matrix metering with AI lenses. The F6 does (and some of the DSLR) but you have to manually enter the maximum aperture in its memory.

In the near future, the small number of humans that are left will prefer photographs that were taken with non-AI lenses, as "non-AI" becomes a marker denoting that the image was not manipulated with the untrustworthy AI technology possibly resident in AI lenses.

The dance with twisting the aperture ring back and forth never really bothers me, but getting the non-AI pin and prong aligned when mounting the lens is just a tiny bit annoying. (If you align them so the body pin is in its detent and the lens is at f/5.6, they line up when mounting, but it's another thing to fuss with while changing lenses).

Only AI-S lenses (not regular AI) have the extra fixed tab at the back of the lens mount that indicates the absolute value of maximum aperture, and only a few bodies actually sense that. I think it's the FA, N2000/N2020 (F-301/F-501), and F4, which can do Program mode with manual focus AI-S lenses. That was rendered moot by the advent of AF lenses and electronic communication between lens and body.

On all regular AI-and-after lenses with an aperture ring, there is a second small tab on the aperture ring, at about 9 o'clock when you look at the lens from the front. I am not sure what that does; I don't think I have any bodies that sense it. I wonder if Nikon added it for some future compatibility and then changed their direction?