Article Index

Lab Tests
Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.


Canon APS-C: Carl Zeiss Sonnar T* 135mm f/2.8 showed very solid but not unique for a medium telephoto lens results in the lab. Performance in the center was outstanding throughout all tested aperture settings. Border performance lagged center a little bit but remained even throughout the aperture range. At its peak from f/2.8 through f/8 the lens would be capable of producing outstanding 16in and decent 19in prints. Conclusion?  The lens performance is right within the range expected from a solid, but not necessarily exceptional, lens and that is all that there's to say about it.

 

MTF50 (Line Width/Inch on the Print) @ 135mm
MTF50 (Line Width/Inch on the Print) @ 135mm

 

Normalized raw MTF50 @ 135mm
Normalized raw MTF50 @ 135mm

 

Like with majority of other Zeiss lenses, chromatic aberration (fringes of color caused by sharp contrast transitions) was pretty much non-existent throughout the tested aperture settings.

 

Image borders @ 135mm (100% crop): f/2.8 vs f/8
Image borders @ 135mm (100% crop): f/2.8 vs f/8

 

Canon FF: The lens continued to perform quite well even on a full-frame camera. Center performance is pretty solid straight from f/2.8 and while performance degrades a bit towards f/11, it never falls apart. Same applies to the border quality, which remains pretty consistent throughout the tested aperture range. Conclusion? While the lens does not produce the best MTF results in its class, very even performance across the frame and throughout tested aperture range should still warrant a closer look at this medium telephoto lens.

 

Normalized raw MTF50 @ 135mm
Normalized raw MTF50 @ 135mm

 

The lens showed minimal amount of barrel distortion - at ~0.22%, distortion should not even register in regular photography.

Distortion (FF) @ 135mm

Distortion (FF) @ 135mm

 

CA was pretty minimal, almost negligible both in the center (~0.4px across tested aperture levels) as well around borders (~0.6px across tested aperture range).

 

Image borders @ 135mm (100% crop): f/2.8 vs f/8
Image borders @ 135mm (100% crop): f/2.8 vs f/8