Quick Test: Sony E 50/1.8 vs Carl Zeiss Planar 50/2 ZM on Sony NEX-7

Today we're going to take a look at Sony's E 50/1.8 lens, one of the newest additions to the Sony NEX lens lineup, and do a quick comparison to one of the best 50mm rangefinder lenses, Carl Zeiss Planar T* 50/2 ZM. The lenses are vastly different in optical construction, build quality, features, but ultimately, both are 50mm primes and can be used on NEX cameras. With the 50mm f/1.8 OSS still being quite hard to come by because of various manufacturing delays that plagued Sony for a few months after the major flood in Thailand, as well as because of the unexpected demand for this lens, users have been resorting to exploring various alternative 50mm lenses. We recently did a couple of such reviews with 8 different rangefinder 50mm lenses (see Alternative 50mm Lenses for NEX), including Zeiss Planar 50/2 ZM. With the final part of that review coming up next week, we will include Sony's 50/1.8 OSS into the group to give you a better idea where the Sony's lens stack up against much more fancy glass. Another comparison but against SLR 50mm lenses will be coming up in mid to late May. But in the meantime, this of this quick test as a preview of things to come. And without dragging things any further, here're our test conditions:

• NEX-7 with v1.0 firmware
• Manual, bracked focusing
• RAW with Adobe RGB color space
• 3m focusing distance
• ISO 400, WB set to Tungsten (2,500K, Tint: 0)
• Adobe ACR with default settings: Blacks +5; Brightness: +50; Contrast +25

Resolution

Both lenses show almost identical performance pattern, although the absolute numbers are obviously different. Both lenses are indistinguishable in the center, but Zeiss shows stronger results around borders, where it leads Sony across all apertures.

Lateral CA

Zeiss is the clear winner here, producing significantly lower amounts of lateral CA around borders than Sony's 50/1.8 lens. Of course the absolute amounts do not necessarily  translate into picture quality, but the lower is still the better.

Vignetting

Sony llooses in this department as well, producing slightly higher vignetting practically across all apertures.

Distortion

Both lenses show practically no distortion - Sony has exibits barrel distortion of ~0.3%, while Planar has ~0.2% of barrel distortion. Either way, distortion is not going to be an issue with either of the lenses.

Conclusion

Not really sure what we expected to see here, comparing a $700 rangefinder lens to a $350 mirrorless lens. Zeiss holds an advantage here pretty much in every function but one - auto-focusing. Sony still performs reasonably well in absolute terms, and so unless you are maniacally obsessed with large format prints, going with the Sony's native lens is probably going to be a smart choice for most users.