Ultra minimal M42 to Nikon F-mount lens adapter

I found an old Carenar lens with a M42x1.0mm threaded mount (not to be confused with T-mount which is a M42x0.75mm thread) that I wanted to use with my Nikon DSLR, but the only adapter I found claimed “INFINITY Focus NOT ALLOWED.” This is because it spaces the lens further away from the image sensor than the lens was designed for.

This limitation can be mitigated if the M42 lens base is in direct contact with the DSLR body's lens mount. This model allows for a secure fitment with minimal material.

Assembly

The threads of the adapter should be a snug fit on your M42 lens. Use a rear lens cap to apply torque if needed. Warm the adapter up and/or go slowly if you are having trouble.

Optional: In order to use the camera body's lens locking pin, drill a small ~3mm hole in the aluminum rim of the old lens (see pic). Use ink or pencil transfer to locate placement. This only has to be about 2mm deep, and does not need to be at the very end of travel of the bayonet turning motion.

Printing suggestion

PLA, 0.1mm layers (0.1mm DETAIL Preset). ETA 13 minutes on a MK3

File note

The proper M42 lens mount is “M42x1.0mm to F-Mount.stl” USE THIS.

A bonus T-mount to F-mount adapter of the same concept is also included as “T-mount (M42x0.75mm) to F-mount.stl” but this does not follow proper image/focal plane norms and will likely make your device Farsighted.

Design and description by Physics Dude , licensed CC-BY-SA.