I tried the Sigma 70-200mm 1:2.8 Macro HSM EX DG APO on my Nikon D5300 and it won't autofocus even though the lens is supposed to have a built-in motor.
I've checked the camera settings to make sure they're set on automatic AF (tried different combinations) but the lens won't focus.
Additionally, there's no M/A switch on the lens. What am I doing wrong?