AF-Nikkor 20mm f/2.8D causes mirror lock up on D750

Just bought a used 20mm f/2.8D lens for my D750. Each shot causes the mirror to lock up. I have to release the lens and turn it twenty degrees to get the mirror to fall again. I love the lens' look but this is unacceptable. Tested my AFS 35mm f/1.8, a 28mm f/2.8D and a 50mm f/1.8D to see if mirror locked up -- maybe the notorious D750 shutter problem -- but no, just this one new lens causes it. Anyone have any idea what is wrong with the lens that would cause this? Thanks for any help.

Sounds as if the aperture actuator lever on the lens is bent or sticky.

 

Best recourse is to return the lens for a refund, unless it was cheap enough to have it repaired, or to attempt DIY repair.

Sounds as if the aperture actuator lever on the lens is bent or sticky.

 

Best recourse is to return the lens for a refund, unless it was cheap enough to have it repaired, or to attempt DIY repair.

 

Thanks for this. The lever was in fact sticking -- I nudged it loose, it seemed to work fine with my finger moving it back and forth, but on camera the lens caused the mirror lock up still, so yes, I will return it. Thanks for your help.

My 20mm f/2.8 AF-D also had the same problem. I bought it as a store demo for for $265 but it had Nikon full 5 year warranty. So I had it for over 4 years when that happened and Nikon fixed it for me free.