Carl Zeiss 24mm MC

[Th3t4]

So I bought this lens off ebay that said it was an MD / MC mount Zeiss (built by sigma in the 90's)

and so I bought an MD/MC adapter from hong kong with an element allowing infinity focus and contacts to change aperture...

small issue, It doesn't even come close to fitting the lens.

Any ideas? I have no ideo what mount this lens is if it's not an MD. there is also scarce literature on this thing as it wasn't very popular...