LensTip.com

Lens review

Canon EF 17-40 mm f/4.0L USM

22 September 2007
Robert Olech

7. Coma and astigmatism

The next off axis distortion coma is corrected very well. At all focal lengths the diode point of the picture is only slightly distorted in the corner of the frame, which is not very problematic.

Canon EF 17-40 mm f/4.0L USM - Coma and astigmatism


The situation with astigmatism is similar. The average difference between the parallel and the horizontal resolution values measured in the center reaches 3.5%, which is a very good result.

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