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Lens review

Sigma 120-400 mm f/4.5-5.6 APO DG OS HSM

20 October 2009
Szymon Starczewski

7. Coma and astigmatism


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Looking at the diode picture at the center of the frame and the corner of it, we don’t see much difference, and this means that coma is corrected in a good way.

Sigma 120-400 mm f/4.5-5.6 APO DG OS HSM - Coma and astigmatism

Sigma does very well with correcting astigmatism. The average difference between horizontal and vertical MTF50 values totaled 4% in this case, which is a very good result.