Max aperture change when use Nikon 60mm AF-D Micro on D90 camera

Question

I found my Nikon 60mm Micro AF-D change aperture from 2.8 to 3.2 when I use it with D90. I was tried A and M mode. It's by design? but Why?.

I intend to buy Nikon 50mm 1.4 AF-D, but it also have a switch button on len (http://www.kenrockwell.com/nikon/5014af.htm) and it will lock maximum aperture at 2.0 (my guess) instead 2.8. So I should buy it or not, or should buy a newer 50mm 1.4 AF-S version?.

Asked by Ngan Pham

Answer

I think you must have noticed something slightly different. The max aperture is a function of the lens and should be unaffected by camera.

The Nikon 60mm Micro AF-D will change its maximum aperture as a function of the focus distance. As it focuses closer, the reported max aperture drops. By life size 1:1, its down to f/5.

There is apparently a button on the 50mm AF-D that will lock its minimum aperture. Many lenses are soft wide open. Locking out the wide open aperture prevents the camera from auto selecting a softer aperture. Since your camera has an in-body focus motor, you're able to use the AF-D or AF-S, you just need to decide if there's a difference for the price that you care about. They'll both take great pictures, the AF-S will just focus faster and quieter mainly.

Answered by rfusca

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