Sony Zeiss Sonnar T* FE 35mm f2.8 ZA lens review: Model behaviorBy Kevin Carter - Monday February 03 2014 Lens Review
The Zeiss achieves a DxOMark lens score of 33 points, an upper mid-to-high score, but perhaps slightly lower than we were expecting.
Sharpness is very good bordering on excellent in the center wide-open but even with a modest f2.8 initial aperture the sharpness falls off gradually at the periphery out to the corners, accounting for around 10% variation across the image field.
Stopping down improves sharpness across the field but the same characteristic fall off in sharpness is repeated at f4 and to a slightly lesser extent at f5.6. Optimal performance is achieved at f5.6-f8 though the softening effects of diffraction can be seen at f11 and onwards.
Chromatic aberration is well corrected across much of the frame save for the corners where it’s evident at all aperture settings albeit at successively lower levels throughout the aperture range.
With a modest maximum aperture you might expect vignetting to be a non-issue but in fact vignetting is quite heavy and, while it progressively lessens as it’s stopped down, it never really clears up. Distortion is a little higher than we would expect as well.