2 replies to this topic

[nruber2019]

      I recently decided to upgrade to full frame and purchased a used Nikon D600. I already own a Sigma 50mm f1.4 EX DG HSM (old version) and I use it on my Nikon D3400. The lens is compatible with full frame, so I had the intention of using it on my D600. However, when I attach the lens on the camera, the AF assist light will flash but the lens does not focus. The motor is not moving at all. It takes photos in MF, but the autofocus just won't work. The lens still focuses fine on my D3500, and other lenses focus when I pair it with the D600. This means it is a problem with just the Sigma 50mm and D600 paired together. I've searched everywhere on the internet for answers and I've tried many things to solve the problem, but nothing is helping. Does anyone have an answer to this? 

[mikew]

What firmware is the camera running, think i read when Nikon updated from 1.02 to 1.03 some third party lenses stopped focusing, normally Sigma would update lenses for you but i have a feeling they dont do this one.

[nruber2019]

That was my problem, my camera was running firmware v1.04, the problem is now fixed, thank you for the help!