Summary

Lightproof mechanical iris for view camera.
I made modifications to http://www.thingiverse.com/thing:773759, for making the thing light-tight. Printed 1,5 scale factor to hold most of my lenses. Got a little hard to move, but made me a favor so no need of a butterfly nut to hold the position.
In the pictures you'll see a photocopier lens, as it's cylindrical I printed a couple of tight washers to hold it in place and also avoid light entrance.
Photos made with this, in wet plate collodion.