An advanced repair project.

This is the original, nearly all metal 50mm f/2.8 1:1 Macro from 1985.
Besides extending the lens to allow 1:1 reproduction, this complex lens mechanism
also moves two lens groups independently, similar to some zoom lenses.
I count 7 concentric tube assemblies.

The lens also features a ball bearing aperture mechanism.

Jammed focus with these old lenses is usually caused by deteriorated tape that was used to
seal the grooves in the mechanism. This repair only requires partial disassembly. The aluminum tape need not be replaced and later versions of the lens do not have it.

The iris mechanism is deep within the the floating element assembly and will require complete
disassembly for repair.