Over the next few days, I intend to work my way through the 24/3.8, 28/2, 28/2.8, 35/1.4, Zeiss 35/2, 50/0.95, 50/1.4, 50/2 APO, 75/2 APO and 90/2 APO, documenting each in a similar manner. Though not every shoot delivers a quality series I deem acceptable, so sometimes I have to reshoot until I am not grumpy about the quality of the example. So this takes time.
The operative question is whether the Sony A7R can replace the Leica M240 using Leica M and/or Zeiss ZM lenses and/or Voigtlander VM lenses, which are a perfect size and weight fit for the A7R
I hugely prefer the manual operation of 'M glass' for some types of shooting (including assurance of zero risk of unwanted focus changes even with camera on/off power cycling). And the actual image question (until Leica ups its game) is whether a 36-megapixel Sony A7R image downsampled to 24 megapixels is worse, as good as, or better than a native 24-megapixel Leica M Typ 240 image. If anyone wonders what else I might be thinking of. Which can mean resolution, color shading, vignetting, and performance across the aperture range.
Zeiss ZF.2 lenses will get a similar treatment, perhaps interleaved with Leica M. But while optically less challenged (ray angle), DSLR lenses compromise the appealing A7R form factor and “carry and support” incur additional concerns. Still the Zeiss 25mm f/2 Distagon is one DSLR lens I can already recommend for the Sony A7R.
I do plan to show select corrected images (Leica, Zeiss, etc) in my review of the Sony A7R, but in-depth analysis and full aperture series of lenses is an appropriate guide issue: M lenses go into Guide to Leica no matter what the digital “back”, especially as more and more cameras emege with their own native lenses and adaptability to numerous other brand lenses.