Re: FM Review of the Voigtlander 40mm f/1.2 Nokton
I can see why Derek likes this lens. If you do get an M mount, a thin filter is a good idea. Oddly, if I removed the filter completely and tried a front end filter, I couldn't reach infinity anymore. I'm skeptical that a PCX fix would allow infinity either, and I'm not quite willing to tear it open looking for shims etc. Planning to convert my A7RII to use a clip in filter anyway, so probably just do that sooner.
To my eye this thin filter is about a stop better. The website says it's a 1.1mm filter, so should be similar to a Kolari V2. If I recall the UT is 0.7mm, probably performs better, but the AWB on this is much better than Kolari's UT (and I think V2, but my memory is murky.)
None of these are centers, wanted to look more at borders and edges.