So today about half way through a shoot I switched from manual zoom to servo and when I first hit the rocker to zoom in servo mode I heard a strange click noise. It has never done this before (I've owned the camera about a month) and continued to do it about every second time I switched from manual to servo for the rest of the night. Just wondering if this is something I should be worried about or if its just the gears engaging? I did a search and couldn't find much so forgive me if the answers already out there.