>>350729455bb
Note there is two, I forget the first ones designation, and the adaptall site is gone now so i cant check, but the one with the tripod attachment thingy is sliiiiiightly technically inferior to the actual 55bb. I don;t even remember why I say that, so chances are they are exactly the same in reality. Maybe the minimum focusing distance was further than the 55BB... that was a determing factor for me back when i was using cats as walkaround lenses to shoot shit on the ground.... anything further than 2m min-focal want close enough for me.
Just keep in mind that you need a fast focusing screen if you want to actually focus it.
Absolutely no microprisms, or split hemispheres.... NONE.
Go for a Canon S type, Super precision matte, (they cut them to fit any camera, got mine for pentax), with no markings , hemispheres, prisms whatsoever. Completely bare.
Trust me on that.
Also it's a relatively small front element, and f/8, so expect to see a very dim viewfinder, moreso with the S type. You just have to deal with it. But know that by being dark you can see contrast and therefore focus better.
https://www.focusingscreen.com/privacy.php?osCsid=cd4b8530a0f34eaf113f5bd9075ccf02 