Visible crew/equipment: When Mulder and Scully enter the abandoned mine through a doorway, the viewer can see at right in the distance a number of people sitting on a wall, and one crouching in front of the wall with what looks like a dog. They are sitting still, but there is still movement there. (00:16:00)
Body Parts - S4-E25
Visible crew/equipment: During a pan-across of Quark's bar after it has been emptied out, the shadow of the camera is visible for a moment in the bottom right corner of the screen. (00:40:35)
Visible crew/equipment: This happens mostly in the first 4 series - crew, lights, and equipment can be seen reflected in the Rangers helmets and visors.