Distagon T35mm f/2
Mounted on an APS-C sensor, this lens is very good for shooting portraits or for reportage. On a full-frame body, it is a solid lens for landscape as well as for reportage.
Interestingly, it reaches its best low-light DxOMark Score as soon as f/2 on an APS-C sensor, and at f/2.8 on a full-frame. These figures are significant, especially when dealing with a fast lens.
The mid-light performance achieves its best score at f/2.8 on a full-frame, but on an APS-C, the lens needs to be stopped down to f/4.
On a full-frame sensor (D3X):
Fully opened, this 35mm offers an interesting field map, the center being already sharp, and most of the frame standing around 50lp/mm. The more interesting being that the corners are almost as sharp as the rest of the field. Stopping down the lens to f/5.6 will increase the size of the sharper central zone without degrading the borders, but without improving them, either.
Vignetting is important at f/2, but it decreases as long as the lens is stopped down. Vignetting becomes limited to the corners at f/5.6.
On an APS-C sensor (D300s):
On a smaller sensor size, the resolution behaves identically, except that the D300s’s 12-megapixel sensor struggles to keep the edges above 40lp/mm. Here again, the optimal range is located between f/2.8 and f/5.6.
Vignetting is noticeable at f/2 but completely disappears as soon as the lens is stopped down to f/2.8 or smaller apertures.
Comparison 1 (On D3x):
Zeiss Distagon T35mm f/2 ZF2 v. Nikkor AF-S 17-35mm f/2.8D IF-ED
Comparison 2 (On D300s):
Zeiss Distagon T35mm f/2 ZF2 v. Nikkor AF-S DX 35mm f/1.8G