Zeiss C Biogon T* 35mm f/2.8 ZM on Sony NEX - Review / Lab Test Report
Lens Reviews -
Sony Alpha/NEX (APS-C)
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Review by Klaus Schroiff, published August 2011
The Zeiss C Biogon T* 35mm f/2.8 ZM is a full format Leica M mount lens. The "C" in the name refers to the "compact" size of the lens which originates in the rather moderate max. aperture. It is the smallest and most light-weight lens in the Zeiss ZM lineup. The Biogon can be easily used on your Sony NEX via a Leica M to Sony NEX adapter (we recommend Metabones adapters).
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 53mm f/4 lens on a full format camera - thus it behaves like a moderately fast standard lens (in terms of light gathering characteristic it remains a f/2.8 lens of course).
Typical for most Zeiss lenses, it's a full-metal construction build to the highest standards - except for the lens cap which feels 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. As usual we recommend this camera-lens combination for static scenes only.
|equiv. focal length (full format)||53mm|
|equiv. aperture (depth-of-field)||f/4|
|Optical construction||7 elements in 5 groups|
|Number of aperture blades||10||min. focus distance||0.7m (max. magnification ratio 1:17)
|Filter size||43mm (non-rotating)|
|Hood||optional, barrel shaped|