The Sony/ Zeiss 55mm f/1.8 Sonnar is the first native FE (Full frame E) I’ve tried on the a7R. This is not a particularly small lens, but it’s very light, and makes for a happy shoulder when mounted to the a7R body.
The first thing I did was check for falloff and color shift, with and without the internal shading correction enabled.
With no correction at f/2, there’s a reasonable amount of falloff but virtually no color cast:
When you turn on the shading correction, the corners are brightened somewhat, but not completely evened out as they are when you use Adobe Flat Field:
As you stop down further, the field evens out, and so does the correction. By the time you get to f/16, the two fields are virtually indistinguishable by just looking, although if you poke around with the eyedropper you can see some small differences..
I set up on the usual medium/long lens scene:
I focused the series presented here manually, but I did a series where I let the camera’s AF have its way with the focusing ring, and it was very close to as good, and probably more repeatable.
Manual focusing on the NEX-7 was an exercise in frustration because the focus-by-wire software wasn’t very good. There’s been a big improvement. In the a7R, the manual focusing isn’t as good as it is with the best old-fashioned helicoid lenses, but it’s not bad at all. It’s actually easier to focus the 55 f/1.8 than it is the Coastal Optical 60mm APO, because the focusing ring on the 60 is so sensitive; a tiny nudge makes a big difference — in its defense, it is a macro lens..
In the center, at f/2 and 1:1, sharpness is really impressive considering the aperture:
At f/2.8, there is significant improvement in both sharpness and contrast:
f/4 is a little better, and f/5.6 is as good as it gets: and that’s really good:
f/8 is slightly softer than f/4, f/11 is as soft as f/2, and f/16 is softer still.
In the upper left corner, there is only a small amount of chromatic aberration, and I had the in-camera CA corrections turned off. It’s a little soft, but considering the aperture, it’s great. Here it is at 1:1:
Contrast and sharpness improve at f/2.8, and again at f/4. It’s even better at f/5.6:
At f/8, it’s about the same. F/11 is a bit softer, and f/16 has the sharpness of halfway between f/2.8 and f/4.
Compared to the Coastal Optical 60mm f/4 APO, in the center, the 55mm is slightly sharper at f/4, and about the same at f/5.6. The 60mm is slightly sharper at f/8 through f/16.
In the upper right corner, the Sony/Zeiss lens is night-and day sharper at f/4 and f/5.6. It somewhat sharper at f/8, a bit sharper at f/11 and about the same at f/16.
Maybe the focus was a little bit better with the Sony/Zeiss lens since I could focus at f/1.8, and I couldn’t focus the Coastal Optical lens any wider than f/4. Maybe I got a really good example of the 55 mm lens. Still, the differences in the corners between this kilobuck lens and one that costs five times as much are truly impressive.
This is a great lens for corner-to-corner sharpness. For the price, it’s flat amazing.