Ill quote:
Autofocus: α7 vs. α7R, or phase vs. contrast-detect autofocus
After shooting several hundred images on our trip with Sony in Tennessee, I found far fewer sharp-focus images from my α7 shooting than from the α7R. Other editors had the same trouble, at least one declaring she had no sharp shots from the α7, while the α7R was fine. Most of the trouble I found was when shooting with the 28-70mm OSS lens, so I switched to the 35mm F2.8 just to get a few more sharp images as we walked around Rock City. I got much better, in-focus images with the 35mm and 55mm lenses.
I haven't had time to pit the two cameras against each other to see if there's a real problem with the kit lens, but there's no question the α7's images are different from the α7R in other ways as well. The α7's JPEG images are more heavily processed with Sony's overaggressive anti-noise strategies. What should be soft bokeh is too often re-rendered as something that looks more like paintbrush strokes than a simple out-of-focus area. We'll be looking in more depth at this in the coming weeks.
So which do I prefer?
After shooting with the α7 and α7R for some time, I preferred the α7R for its faster, more reliable autofocus and better images overall. Naturally, I wanted to prefer the α7, with its lower-res 24MP sensor and lower price. The main reason I preferred the α7R: I liked the images better, and I liked the experience better. The α7's JPEG noise suppression looks quite overprocessed, giving even out-of-focus areas a brush-stroke appearance, and its phase-detect autofocus isn't as fast, nor as accurate (we'll be testing further to confirm and characterize this). With either camera, I would like a way to lock the EV compensation dial, but I could very easily see using the α7R as my main camera for a number of uses, including portraiture (if anything, its detail is unnecessarily high; hence my wish that the 24MP α7 were a little better).