Sigma 17-50mm f/2.8 EX DC OS HSM DEAD OS???
I can clearly hear the OS activate and deactivate on the sigma 70-200 OS and when OS activates, I see a slight shake looking through the view finder. Ii can barely even hear the OS on the 17-50 and sometimes I don't think i can even hear it.
I hear a sound that is probably the OS when i turn the camera (D5100) off.. normal?