When the drill thrall brings Chekov his meal in his cell, every time the camera focuses on Chekov sitting on the bench the shadow of the boom mic can be seen hovering on the wall behind him, just above his head.
At 8:55 Kirk, Uhura, and Chekov fall to the ground writhing in agony. The Steadicam operator moves in for a close-up of Chekov and captures and piece of camera equipment sitting of the floor. He quickly pans to the right.
When Kirk, Uhura and Chekov first attempt to fire their phasers, the small light at the tip is visible in a close-up. This light in the prop is worked by the trigger and is there to synchronize the firing of the phasers with the special effects added in post-production.