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Sony NEX-5 with alternative lenses and color color shifts / vignetting



The Sony NEX-5 and NEX-3 cameras are at the time of this writing somewhat unique cameras. For a modest price, they offer an APS-C sized sensor (a 1.5x crop factor) in a body not much bigger than a point and shoot. They also have a tiltable LCD screen and an interchangeable lens system. At the time of this writing, only two lenses are available for the E-mount (the same that Sony has given to this new mount), the relatively slow 18-55 kit zoom lens and a 16mm f/2.8 compact prime. However, due to the short distance between the mount opening and the sensor, its possible to attach virtually any lens for any other system onto these cameras by using an adaptor.

In this review, I want to focus on a selection of Leica M mount Voigtlander and Zeiss lenses. These lenses are preferable to lenses from many other systems since these lenses were designed for a very short mount to film distance, hence they have great image quality in very compact sizes. One issues however that comes up is corner vignetting and color shifts. The reason this happens is because light arrays refracted by some of these lenses don't hit the sensor plane at perpendicular angles (especially for wide angle lenses). Since many of these lenses were designed for film, this isn't an issue with film, but is with a digital sensor (has to do with microlenses and such which I won't go into at this time).

The question that comes up is with what lenses can this vignetting / color shifting be seen? Hence this test.

Tests

Images were converted in Lightroom 3.2, sharpening left at default values. All white balances were adjusted to be the same (5200, -8 tint). I used a tripod for all the images and used the Voigtlander M to E-mount adaptor. Aperture was set to f/8 and exposures fixed at 1/250s and the ISO fixed at 200.


Mouse-over apertures to compare. Top row is for the Nex 18-155 kit lens, bottom row is the alternative glass
18mm 23mm 35mm 52mm
Voigtlander 15 Zeiss 18 Zeiss 21 Voigtlander 35 Voigtlander 40 Voigtlander 50

Conclusions

Its pretty clear that the Voigtlander 15mm exhibits very noticeable vignetting and color shifting. This can be seen in a variety of scenes, indoors and outdoors. The Zeiss 18mm f/4 Distagon also seems to have some noticeable corner color shifting. However, if you shooting things were there is corner detail, its unlikely you will notice the color shifts (especially if you aren't shooting blue skies). The Zeiss 21 f/2.8 Biogon when compared directly to the kit lens shows some minor color shifting. I would argue its minor enough to not be a big deal. The Voigtlander Nokton 35mm f/1.2, 40mm f/1.4 and 50mm f/1.1 also show no signs of corner vignetting or color shifting.

My intent is not to knock the lenses that exhibit corner color shifting. What these small web sized images don't show is the superb sharpness, contrast and micro detail that all of these lenses exhibit, especially when compared to the 18-55 kit lens. I'll examine some of these lenses a little closer in future articles.

As an aside, I should say that the Zeiss 21mm f/2.8 Biogon is growing to come one of my favorite lenses for the NEX-5 (along with the Nokton 40). Even wide open, the ZM 21 is sharp and has great color and contrast.


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All text and images (c) 2000-2017 Aravind Krishnaswamy. All rights reserved.