This adapter is constructed in two pieces: on the lens side a nickel-chrome alloy is used, on the camera side aluminium. A "lip" construction prevents unwanted back-scatter of light into the camera body.
Please attach adapter to lens first, then the assembly to the camera body. Lens cannot be changed while adapter is attached to the body.
Lenses that cannot be used with this adapter: G lens type without aperture ring, Nikkor-O 21mm F4, Nikkor-S 50mm F2 (pre-Ai types) cannot be mounted. There might be other, more obscure lenses that cannot be used that are not listed here.
Zeiss Ikon Planar 50mmF1.4 ZF lens has been tested and confirmed as usable.
The following lenses have a protruding rear portion that may touch or scratch the EOS camera's mirror box: 50mm F1.2, 55mm F1.2, NOCT 58mmF1.2. These lenses need to be altered (about 0.3mm needs to be taken off the intruding part) to be used carefree.