Wow!!
Someone commented something similar on a thread, I was not able to finish some (most) stacks of water mounted specimens with OIL objectives, I thought the pressure of the objective on the coverslip was causing this but I just realized is the second curtain shutter shock, it transmits the vibration through the objective to the immersion oil and then to the coverslip and specimen. I do not have this problem with AIR objectives.
Seems I will have to look for a camera with full electronic shutter or find a way to suspend the camera on top of the microscope without touching it, I am waiting for a second hand Nikon J1 and I will try first with that
My cameras are Sony NEX-5N and A5100; maybe other option is to mount the camera on an arm on the wall or something...