My main concern about the Sony bodies has been how well they'll work with 35mm M lenses. I'd ordered an A7r, but following advice from RFF and LUF re: corner smearing and vignetting, I returned it unopened and got an A7.
Today I tried the Summilux Asph FLE, two Mandler designs – 35 pre-aspherical Summilux and 35 Summicron v4 – and a 40mm Summicron. I tried them at widest aperture to f4, thinking that the A7, with better high ISO performance, would be my body of choice for low-light-level shooting. (When I can use lower ISO's, I'll stick with M9.) I used a Voigtlander adapter, which is quite solid. I photographed a blank garage door to look for color vignetting, and a fence with both vertical lines and mesh to check for corner smearing.
I tried the Lux FLE first with high hopes, but it exhibited some color vignetting at all apertures and quite a bit of corner smearing: lots of it at f1.4, moderate at f2.8, and perhaps just tolerable at f4. I won't be using this lens on A7.
The 35 Cron v 4 performed better than the FLE, but still not too well. At f2 I saw moderate color shift, and vignetting in the corners. At f4 it was still vignetting, but the color shift seemed less. At f2 it smeared less in the corners than the FLE – smearing was limited to the far corners of the frame. At f4 it might be tolerable, but it's so much better on M9.
The 35 pre-aspherical Summilux and the 40 Summicron were both better, but for different reasons.
The PA Lux at f1.4 showed quite a bit of luminance/BW vignetting but much less color shift in the corners. This is probably be reparable in LR/PS withe the regular vignetting correction tool (no need, I'm guessing, for the new and complicated flat field plug-in). It showed only a little bit of corner smearing at f1.4 and f2, and none at f4. IMO this is a usable 35mm lens for A7 when one needs wider apertures.
The 40 Cron Was best-of-all for avoiding smeared corners – visible only in the extreme corners at f2 and f2.8; none at f4. When looking at the 100% crops of the corners I could tell I was looking at symmetrical bokeh, not elongated smear. The downside, however, was that this lens vignetted quite a bit – luminance vignetting without serious color shift – even at f4. Perhaps it wasn't comfortable in the Voigtlander adapter, and I wonder if Novoflex would be just be the same. (It doesn't do this on M9, because it's been coded to use the 35 Cron lens profile.)
My own conclusion is that I won't be using the 35 Cron v4 or the Lux Asph FLE on the A7 body, and will probably make the 40 Cron my regular moderate wide angle. Subjectively I like the PA Lux best of all, but am always afraid of its characteristic moon-shaped flare when there's a light source just outside the frame.
These are tentative first-days-with-the-camera pixel-peeping checks to see what lenses to go ahead and use. I might change my mind later.
I'm also going to check some 50s this weekend. A first look suggested the pre-aspherical Lux performs noticeably better in the corners than 1.5 Sonnar-C. My Lux is a minty black paint one, worth quit a bit more than either an A7 or A7r body; so I wish it had turned out the other way!
Kirk
