Autofocus Converted Contax N Test: 17-35mm f2.8

Contax N 17-35mm f2.8 v Nikon AFS 17-35mm f2.8

Distortion Control: 17mm (full frame)

Precisely the same distortion pattern is evident at 17mm in both lenses. The extent of the Nikon's barrel distortion is clearly more severe.

Distortion Control: 21mm (full frame)

At 21mm, both lenses are equally en-route to pincushion distortion: the Contax is ruler perfect here; the Nikon requires an extra 1mm or so to iron out the last wrinkle of barrel distortion.

Performance at 24mm: (full frame)

The Nikon's upturning corners are complicated by barrel distortion in the centre frame: much like a Zeiss 21mm. The Contax suffers from the problem, too, but to a less degree.

Performance at 35mm: (full frame)

The 24mm range remains the most troublesome for both lenses in terms of distortion: by 35mm, the pincushions have deflated and both lenses are rather more neutral. A decent prime in this range would normally show traces of negative rather than positive distortion.

All in all, then, a clear victory for the Zeiss Contax (5 points): exactly the same quality of distortion, there's just less of it. Finally, we review their control of chromatic aberration.