dPreview om AF A7 vs A7s
Det här är konstig läsning och borde inte stämma. Möjligen är det något halvfel på A7 de fått om AF i A7 är långsammare än A7r. Att den missar fokus mer kan ju bero på att AF är dåligt kalibrerad. AF kan ju som alla vet bli "fort men fel" i värsta fall.
Läs själva:
"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.
Low light
I was impressed with both cameras' performance in low light. As I mentioned, I got better autofocus in low light from the α7R, but image quality from both was very good in low light, such that I had no trouble letting the camera's ISO rise to 6400.
Lenses
The three FE lenses we had to shoot with were the Carl Zeiss 35 F2.8, the Carl Zeiss 55mm F1.8 and the 28-70mm F3.5-5.6 OSS lens (a Zeiss 24-70mm F4 lens is planned, but we've not seen one yet). All three are well built, but only the 35mm keeps the α7 and α7R small; the other two are quite a bit longer, particularly with their lens hoods mounted. The 35mm's lens hood is tiny by comparison. Overall, I preferred working with the 35mm lens. There's some wobble as it focuses, but it's quick, and focus is usually pretty accurate. Oddly, there's more wobble with this lens on the α7 than on the α7R.
Indeed, I found the α7R easier to use with this lens, getting faster autofocus than I got on the α7. Again with the 55mm, autofocus was more sure and swift with the α7R than with the α7. That runs counter to what we'd expect from phase detect autofocus, so it warrants more testing.
In low light, the camera's AF illuminator would come on to help focus, which wasn't always much help at all, especially with near subjects. Too often it overwhelmed the scene, and I found simply blocking the AF-assist lamp resulted in faster, more accurate autofocus, which suggests that turning it off is probably a better option.
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).
r inte duger så kan jag komplettera med FE 35/2,8 och sluta på ungefär samma totalpris som bara R-huset kostar. Med bättre AF och tystare slutare därtill.
