Listers,
I recently purchased an old Nikon 135mm lens and it will not mount to my d7000. It seems that it might not be AI converted. ???
I have several other lens from the era and they all fit and work as they should.
Please what should I look for?
When I got my D3200, I found that one of the three old non-AI lenses that I had for my F2 would not mount properly on it. The other two mounted and worked just fine, but this one would not rotate all the way to the click/lock position.
It took a careful examination of this lens, and a comparison to the other two, to figure out what the problem was. Some previous owner had obviously disassembled it, and not correctly reassembled it. It was a very subtle error, that didn't affect mounting this lens on my F2, and probably didn't affect any other camera on which this or any subsequent owner before me ever tried to mount it, but it did affect mounting it on my D3200, and would probably affect mounting it on your D7000.
Have a look at this picture.
There are three screws like this around the mount in this slot. One of them is different than the other two. Two of them have heads such that the top of the head is flush with the surface of the metal. The third one, pictured here, has a different head, that sticks out a bit above the surface.
The non-flush screw, that sticks up, belongs on the “bottom” side of the lens, 180° away from the dot on the top that you use to align the lens with the corresponding mark on the camera when you are mounting it. Whomever had previously disassembled and reassembled this lens had erroneously swapped this screw with one of the flush screws. There was a flush screw in the bottom position, and this non-flush screw in one of the other positions; and it was the improperly-placed non-flush screw that was preventing this lens from properly mounting on my D3200.
Once I swapped this screw back to its correct position, putting the flush screw that was there in the position where I found the non-flush screw, the lens thereafter mounted and worked just fine on my D3200.