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Lens review

Carl Zeiss Batis 25 mm f/2

15 September 2016
Szymon Starczewski

7. Coma, astigmatism and bokeh

Noticeable but not especially pronounced coma problems can be experienced at the maximum relative aperture. A delicate deformation of the image of a diode happens already in the corner of the APS-C sensor; it becomes distinct in the corner of full frame. Visible improvement can be achieved by stopping down the lens to f/2.8 - after that even the corner of full frame looks quite sensible.

Center, f/2.0 Corner APS-C, f/2.0 Corner FF, f/2.0
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh
Center, f/2.8 Corner APS-C, f/2.8 Corner FF, f/2.8
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh


Photos of the starry sky provide similar effect. Deformations aren’t huge but you can notice them without any problems; still taking into account the aperture fastness of the lens and its wide angle of view you shouldn’t complain too much.

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A7R II, JPEG, f/2.0, right upper corner of the frame 1:1
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh
A7R II, JPEG, f/2.8, right upper corner of the frame 1:1
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh


The astigmatism, understood as an average difference between vertical and horizontal MTF50 function values, amounted to just 3.9% and shouldn’t be a distinct or noticeable problem.

Zeiss got us used to nice out-of-focus areas and circles with a very even light spread. Unfortunately the Batis 2/25 doesn’t fit that picture at all. There are many distinct ‘onion rings’ in circles generated for our test and on stopping down a lighter rim appears as well. Luckily the mechanical vignetting doesn’t seem especially pronounced.

Center, f/2.0 Corner APS-C, f/2.0 Corner FF, f/2.0
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh
Center, f/2.8 Corner APS-C, f/2.8 Corner FF, f/2.8
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh
Center, f/4.0 Corner APS-C, f/4.0 Corner FF, f/4.0
Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh Carl Zeiss Batis 25 mm f/2 - Coma, astigmatism and bokeh