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

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

Conclusion

Purely considering 'sharpness' (accutance, resolution, microcontrast) which is the entry-level requirement for a lens – it's ability to deliver maximum reality to the sensor – we might summarise the findings broadly as follows:

• At 17mm, the lenses are a dead heat.
• At 21mm, the lenses are very, very similar, but the Nikon is slightly better.
• At 24mm, the Nikon is undeniably better.
• At 35mm, the Nikon is slightly better.

We might add to this summary that the Nikon's advantage lies mainly in its excelling f8-f11 performance. Your own particular shooting priorities will determine whether that factor is important or not. If you work mainly at f11, that factor alone might bias you in favour of the Nikon.

However, if we broaden our definition of performance to include flare resistance and correction for distortion and chromatic aberration, the Contax holds all the aces. It handles bright lights with uncommon aplomb and is exemplary with regard to colour fringing. With greater or lesser impact on the rendering of fine detail, many of these traits can be considered post-production issues, and I would claim are of lesser importance if we're simply addressing the lenses' ability to deliver stunning images, without reference to productivity.

However, not to be underestimated is the sheer practicality of having such high quality optics mated with the convenience of autofocus and auto-aperture. Occasionally, you will get shots with the Contax that you would miss while faffing about with the Nikon's manual controls on a Canon body.

In terms of build quality, reliability and handling, they are both indisputably from the top drawer. In terms of cost, the Contax is a lot more expensive, but it could hardly be considered overpriced when you consider the package you get. And the Conurus conversion is irreproachable.

Whether the Contax is the lens for you will depend much on your preferred working methods, post-production skills and priorities: are you intending to use the lens primarily at 17-24mm or the 24-35mm? If the latter, you'd be better off hunting down a good copy of a Canon 16-35L or Leica 21-35mm. If you're looking for the best thing in the 19-23mm range, I'm afraid there is no substitute for the Distagon 21mm at the time of writing.

If you're wondering whether the Contax N 17-35mm is the next best thing, it may well be: but if you can live without the automation, and are prepared to build a few extra Photoshop actions into your workflow, the Nikon 17-35mm f2.8 will deliver equally stunning images for a lot less money.

The reason for this was explained at the end of Part I: if the Contax didn't suffer from a torus of low resolution around the centre frame, particularly at distance, it would be so much better than the Nikon you could cry. In response to questions about the size of 'Area B', I've added blue and red overlays to the Contax 17mm shot to show where it underperforms and outperforms the Nikon which, coincidentally has exactly the opposite problem. Here, blue is good (for the Contax) and red is bad. As you'll notice, the worst of it is all at middle distance: at short range the problem was less evident in the test shots.

The final score, via our most recent, pretty arbitrary, grading system that simply puts a notch on the belt of the lens that performs best in each subcategory (ie, 24mm / f5.6: corners), proved to be 33 points for the Contax and 53 points for the Nikon.

For further details of how the lens compares to the Canon 16-35mm L and Zeiss 21mm, please refer to the main index page.