I showed this in another thread:

Leica M-P typ 240 fitted with Leica Elmarit-R 19mm v1 lens via Kipon LER->LEM mount adapter. Olympus VF-2 and cable release fitted, along with 52" Street Strap.

Testing showed that it needs some lens profiling to work correctly, there's a good bit of vignetting with the camera set to "no code" at all apertures. I haven't re-ordered the R-Adapter M yet so I 'm not sure how much of it the R lens codes that brings up will help.

I did a little bit of experimentation with a test exposure yesterday. I wanted to see how much correction I could do using what LR 5.7.1 comes with and how the Adobe Flat Field plug-in might help in addition.

Looking through my test images, the lens plateaus at f/5.6-f/8, so I picked f/5.6 and between 5 and 6 foot focusing distance to experiment with, a useful distance for what I do with an ultrawide like this. I have to work in close with this wide a field of view ...

Oh, and don't tell your model about wide angle distortion. It's not very flattering. ;-)

The results came out like this:

Like a dummy, I'd not compensated for the white wall so I added 1.33 stops exposure to the test in Lightroom. And I set the FF plugin to only do intensity correction, not color. The FF calibration image was made using a flat panel light box, with the lens at f/5.6 and 5.5 feet settings, just pulling it close enough to fill the frame.

All in all, very pleasing results both with the CV lens profile for casual work and with the FF plugin for more demanding situations. The lens shows little color shifting or rectilinear distortion, and with these aids the light falloff becomes manageable.