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

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

Performance at 17mm: f11 (Centre Frame)

Contax N 17-35mm at 17mm/f11	Nikon 17-35mm AFS at 17mm/f11
1 point	1 point

Performance at 17mm: f11 (10mm off-centre, left side)

Contax N 17-35mm at 17mm/f11	Nikon 17-35mm AFS at 17mm/f11
0 points	1 point

Performance at 17mm: f11 (upper right corner)

Contax N 17-35mm at 17mm/f11	Nikon 17-35mm AFS at 17mm/f11
1 point	0 points

Later on, we'll see in greater detail the Nikon's CA gremlins in the 17–19mm range, but the Contax 17-35mm is as clean as a whistle. The Nikon predictably spreads its high-resolution rendering into the corners as it is stopped down, and by f11 is (almost) capable of what the Contax could do at f5.6. Even here, though, with a full frame sensor it stops just short of delivering entirely to the cornermost pixel, enabling the Contax to sneak an extra point. As at was at f8, centre frames at f11 are inseparable.

At all apertures, the Contax fails to deliver uniformly across the frame. I strongly suspect, however, that most users won't notice: without the same image produced by a Zeiss 21mm or Nikon 17-35mm jammed up against it, the Contax looks great. Trouble is: once you know the flaw is there, it won't go away.