The Zeiss 16-70mm F4 ZA OSS optically stabilised, 24-105mm equivalent standard zoom lens test results shows the lens score of 15 points and performed a good optical performance. The lens tested on Sony NEX-7 mirrorless camera.
According to DxOMark test, they find the lens sharpness is high centrally at the shorter focal lengths, but it achieves more uniform performance across the field in the middle of the zoom range, as is so often the case.
Sony Zeiss Vario-Tessar T* E 16-70mm F4 ZA OSS Lens Gets DxOMarked
From DxOmark review:
Although the overall DxOMark score is perhaps a little discouraging for a $1,000 stabilized zoom, the Sony Zeiss E 16-70mm f4 OSS actually has a good balance of sharpness and uniformity. It has low chromatic aberration, and distortion at 16mm is very well corrected, even if it’s bordering on the difficult to correct complex type. It might not wow users at either end of the zoom range, but it does in fact have excellent performance at 35mm.
The Zeiss 16-70mm f4 features 16 lens elements in 12 groups, with an iris diaphragm featuring 7 rounded aperture blades. Weighing in at 308 grams, the Sony Zeiss Vario-Tessar T* E 16-70mm f/4 ZA OSS takes 55mm filters, and offers a 0.23x magnification and a minimum focus distance of 35cm.