Zeiss Sonnar T* 135mm f/1.8 ZA (Sony SAL-135F18Z) - Full Format Review / Test Report
Lens Reviews - Sony Alpha (Full Format)
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Review by Klaus Schroiff, published March 2010

Special thanks to Dieter Scherk for providing this lens for testing purposes!


The Zeiss Sonnar T* 135mm f/1.8 ZA (SAL-135F18Z) is one of the primary differentiators of the Sony Alpha system - apart from carrying the legendary Zeiss brand name it's also the fastest 135mm AF on the DSLR lens market. Zeiss lens designs are categorized by a naming convention - citing Wikipedia: "The Sonnar is a photographic lens design originally patented by Carl Zeiss, notable for its relatively light weight, simple design and fast aperture. The name "Sonnar" is derived from the German word "Sonne", meaning sun. It was given this name because its large aperture (...)". The idea may be old but the Sonnar T* 135mm f/1.8 ZA is an all-new design with no real ancestors - it takes advantage of 2x ED elements which is the most striking difference compared to the more conventional design of the 85mm f/1.4 ZA. The Zeiss lens covers the full 35mm format where it would be typically described as a lens with an emphasis on portrait photography.

The build quality of the Zeiss lens is excellent also thanks to an all metal construction. The focus ring is decoupled from the AF gear so it does not rotate in AF mode. In manual focusing mode it operates very smooth but there is a little play when changing the focus direction - this is typical for non-SSM Sony lenses. The lens does not extend during focusing operation which is different compared to the 85mm f/1.4. The front element does not rotate thanks to an IF (internal focusing) design. Unfortunately there're no seals against dust and humidity - something which should be standard in this lens and price class.

It is not a show-stopper but the AF system of the Zeiss lens does still rely on the rather outdated classic focusing system driven by the camera (via a slotted drive screw). Sony's modern SSM (supersonic motor) would have made more sense here. As a consequence of the conventional AF system the lens produces a moderate degree of noise during operations. Due to the heavy weight of the lens system the AF speed is quite fine but not great.

Optical construction11 elements in 9 groups inc. 2x ED elements
Number of aperture blades9 (rounded)
min. focus distance0.72 m (max. magnification ratio 1:4)
Dimensions89 x 115 mm
Weight1050 g
Filter size77 mm (non-rotating)
Hoodmetal, barrel-shaped, snap-on-type, supplied
Other featuresfocus stop button

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