Zeiss Biogon T* 28mm f/2.8 ZM on Sony NEX - Review / Lab Test Report
Lens Reviews - Sony Alpha/NEX (APS-C)
Saturday, 30 July 2011 20:05
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Review by Klaus Schroiff, published August 2011

Regarding the current lack of native E-mount lenses many Sony NEX users are looking beyond the Sony lineup. The Leica M world offers a wealth of small primes lenses which can easily be adapted e.g. via a Leica M to Sony NEX adapter (we recommend Metabones adapters). Original Leica M lenses tend to be prohibitive from a pricing perspective but the Zeiss ZM and Voigtlander VM offerings are actually not totally out-of-reach. This time we will have a look at the Zeiss Biogon T* 28mm f/2.8 ZM which is available either in silver or black.

Such adapted lenses can only be used with manual focusing and "working aperture" - there's no data coupling whatsoever here. However, due to the lack of dedicated prime lenses in Sony E-mount it's surely one of the more interesting fall-back solutions for the NEX-system. In terms of field-of-view and depth-of-field it is equivalent to a 42mm f/4 lens on a full format camera. While not terribly exciting regarding shallow depth-of-field photography it remains a viable option for street photography for instance. At around 850EUR the Zeiss lens is far from being cheap though but let's have a look whether it is worth it.

Typical for most Zeiss lenses, it's a full-metal construction build to the highest standards - except for the lens cap which is rather crappy.The focus ring operates as smooth as silk (dampened). The aperture is set in 1/3EV steps at the front of the lens. Any change of the aperture is applied immediately so you can check the effect on the depth-of-field on your screen - without the darkening like on DSLRs when adapting non-native focus lenses). The lens extends marginally when focusing towards closer focus distances. The front element does not rotate.

Manual focusing may sound like a major annoyance but it is not that bad actually. Recently Sony added "peaking" focus support to Sony NEX cameras which is already helping a lot here. Other than that you can easily switch to a magnified focus view so accurate manual focusing is really simple ... unless you try to track a moving object of course. We recommend this camera-lens combination for static scenes only.

Equiv. focal length42 mm (full format equivalent)
Equiv. aperturef/4.2 (full format equivalent, in terms of depth-of-field)
Optical construction8 elements in 6 groups
Number of aperture blades10
min. focus distance0.5 m (max. magnification ratio 1:16)
Dimensions53 x 62 mm
Weight220 g
Filter size46 mm (non-rotating)
Hoodoptional, barrel shaped
Other features-