Zoom gear that fits over a Panasonic 12-35mm lens for use in a Nauticam underwater housing. Fit can be a bit tight. Need to install from the rear of the lens before putting lens on camera.
Update 2018/04/01 : thanks to François C., this is a new version with larger "window" for power-ois button (i hope that this one is large enough) and little bit larger for inside part (67,4 mm).
Start from scratch :-)
First of all i'm very "new" with 3d design and printing ... so for my first zoom gear (the 12x60) i start with an other one i download on thingiverse ... but now i know how to make a "InvoluteGear" with freecad :-)
So it's easy with that !
Step 1 : Involute Gear
Step 2 : Extrude
Step 3 : Add cylinder
Step 4 : remove internal cylinder
Step 5 : add window
Step 6 : remove half involute gear