Photo detail

Camera Maker Nikon Corporation Camera Model NIKON D90
Aperture f/3.5 Exposure Value 0 EV
Exposure Program Unknown: 0 Exposure Time 1/60 sec
Flash Flash, Auto-Mode, Return light detected Focal Length 18 mm
ISO 800 Metering Mode Pattern
Date/Time 2016:03:16 18:55:10 Resolution Unit Inch
X Resolution 240 dots per ResolutionUnit Y Resolution 240 dots per ResolutionUnit
Compression Jpeg Compression Contrast 0
Exposure Mode 0 Saturation 0
Scene Type Directly Photographed Sharpness 0
Subject Distance 0.47 Caption The spur gear servo motor drive turns the worm gear on the far side. You can see the black encoder on the back of the servo and the PEC reference sensor on the main worm gear shaft. The spur gears connecting the motor to the output shaft are typically covered with a shroud. Not sure why my unit doesn't have it. Also not sure why they need a 1:1 gear vs. finding the space to direct drive the worm and eliminate that additional point of play.