Leica M mount adapter for Ursa Cine 12K LF prototype

[eatstoomuchjam]

(Cross-posted from reddit)

I've been working on and off for a while now on a Leica M mount for the Ursa Cine 12K LF. I was having problems with minor flexing in the plastic - and the random Micro 4/3 to M mount adapter that I used as a donor turned out to be a bad choice for a few reasons.

In the meantime, I found some ways to mitigate the plastic flexing and I disassembled a Fotodiox L mount to M mount adapter and found it a lot more suitable, plus with a larger diameter which also seems to help with stability. Because of shape of mount cavity on the camera, the lens also needs to be mounted upside-down with my mount.

Unfortunately, there is some play in the adapter so any lens will need support if racking focus.

This latest prototype still focuses just a little too much past infinity with the f/1 Noctilux so I have one or two more prototypes to dial it in just a little closer - and then I'll switch from the cheapest PLA in my house to PCCF and print what I hope will be the adapter that I actually use.

Limitations? Every modern Leica M lens that I own (21, 24, 35mm) that is 35mm or wider cannot be used. They stick out past the rear of the mount and would impact the glass in front of the ND filters. Similarly, with my Simera-C set,

However, my incredibly old 35mm/3.5 Elmar does not protrude and, as can be seen in the couple of snapshots I took from the last round of testing, works great (and is beautiful, as it is on any camera). That's the widest L mount lens that I own that can fit.

HOWEVER

While using my M mount glass is part of my goal in building this, the bigger bonus is that having a Leica M mount lets me adapt a bunch of other vintage SLR glass that is not otherwise usable (without mount conversion) on the UC12K LF. And since those lenses were designed for SLR's, the wide angles don't protrude. This will address one of the few things that I've found to be a bummer - I really love my FD mount and Minolta SR mount glass! With an FD to M mount adapter, they will all be 100% usable now.

In this round of testing, I checked the 50/1 Noctilux and the 35/3.5 screw mount Elmar - both are gorgeous lenses on any camera that I've put them on and this is no exception. Did some 3:2 frame grabs from Resolve with no grading done beyond slapping on a BMD film to rec.709 lut. I also seem to have done the math wrong for a 3:2 ratio in Resolve, but I'm also not going to bother going back to fix the slight letterboxing.