CS/C-Mount Lens Backfocus Adjuster. For machine vision or scientific application. This appears to be a porthole type camera from a machine, with a large backfocus adjustment range for short working distance. This previously held a 25mm lens (see my other listings). I do not have any specs or know previous application.
Note: the brass portion has a 1" threaded hole for CS/C-Mount lens. I imagine you must use a CS-mount lens to preserve infinity focus, but I have not measured or tested this.
