Monday 9 January 2012

Sony NEX-7 - Voigtlander lenses in use

Sony NEX-7 Voigtlander 35mm f/1.2 Nokton
Sony NEX-7 Voigtlander 35mm f/1.2 Nokton

Until yesterday, I'd only done some indoor tests with the Voigtlander 35mm f/1.2 Nokton and 75mm f/2.5 Heliar lenses on the NEX-7. Though these were very impressive, I needed to try them out in a real world situation. 

Sony NEX-7 Voigtlander 35mm f/1.2 Nokton
Sony NEX-7 Voigtlander 35mm f/1.2 Nokton

Sony NEX-7 Voigtlander 75mm f/2.5 Heliar
Sony NEX-7 Voigtlander 75mm f/2.5 Heliar

I'm pleased to say that the promise of the testing was confirmed by this excursion. Very sharp results, with I'm pleased to say, very little CA and fringing once the lenses are stopped down from their widest apertures, plus excellent colour and contrast.

I seem to be whittling down the number of lenses I actually want to keep for the NEX-7, and its proving more difficult than I thought. The NEX-7 seems to throw more challenges at lenses than the NEX-5n. Not in terms of sharpness, as everything I've put on it so far has performed well or adequately in that regard (with one exception I'll come to later*) but in terms of CA, fringing and vignetting. 

These two Voigtlanders, however, are the equal of the Zeiss 24mm f/1.8 in terms of resolution, and apart from their fine performance, I really enjoyed using them. With the excellent focus peaking feature, they were a pleasure to use, and this Sony innovation really does open up the possibility of being able to use manual focus lenses with speed and accuracy. I'm sure something similar will start turning up soon in other CSC's, and I wouldn't be at all surprised if Leica are having a look at it, not neccesarily for their m-series cameras, but for this interchangeable mirrorless system they are apparently working on. 

Sony NEX-7 Voigtlander 75mm f/2.5 Heliar
Sony NEX-7 Voigtlander 75mm f/2.5 Heliar

Sony NEX-7 Voigtlander 35mm f/1.2 Nokton
Sony NEX-7 Voigtlander 35mm f/1.2 Nokton

Sony NEX-7 Voigtlander 75mm f/2.5 Heliar
Sony NEX-7 Voigtlander 75mm f/2.5 Heliar

THE PROBLEM LENS
Sony NEX-5n Voigtlander 28mm f/2 Ultron
Sony NEX-5n Voigtlander 28mm f/2 Ultron

*The third of my Voigtlanders, the 28mm f/2 Ultron, however doesn't work very well at all. Apart from the vignetting and colour cast, its just not that sharp. In contrast to its performance on the NEX-5n, when it was very good indeed.

The problem seems to be that this Voigtlander is a symmetrical design (as opposed to retrofocus) There's a link here to a piece by Carl Zeiss on the difference. Not only is there a tendency to the vignetting and colour cast problem illustrated in an earlier post, but with certain types of sensors, there can be a reduction in sharpness also. 

Apparently this is the reason that Ricoh designed their m-mount module for the GXR system in the way that they did. According to my internet research on this, the NEX-7 sensor is configured in such a way as to make symmetrical lenses perform less well than on the NEX-5n, which is a different design. I'm not going to explain why this is, as I simply don't know enough about it to enlighten you, but I've most definitely seen it in operation, and what was a very good lens on the NEX-5n has suddenly become a quite poor one on the NEX-7. 

There are 28mm Leica lenses which apparently work fine on the NEX-7. Unfortunately they are substantially more expensive than my humble little Voigtlander, which seems to have accepted its fate and realised its destined for a new home anytime soon!!

So, the NEX-7 seems to be a demanding beast! In order to squeeze out the best value from those 24MP, it gets very picky about what works with it and what doesn't. I am prepared to continue trying to sort out my best options however, since when it gets it right the results are spectacular. Now can I really afford £4000 for that Leica 16-18-21mm Tri-Elmar, because apparently that works brilliantly with the NEX-7? No I can't. That was easy!!