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Lens review

Sigma A 60 mm f/2.8 DN

6 August 2013
Arkadiusz Olech

7. Coma, astigmatism and bokeh

The tested Sigma 2.8/60 doesn’t have any problems with the coma on the small Micro 4/3 sensor. At the maximum relative aperture, in the very corner of the frame, the diode is deformed just slightly which means that aberration is corrected well.

Sigma A 60 mm f/2.8 DN - Coma, astigmatism and bokeh

The astigmatism won’t be an issue either. The average value between horizontal and vertical MTF50 function values amounted to 4.5%. What’s interesting the astigmatism was a bit higher by f/4.0 than at the maximum relative aperture.

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When it comes to the appearance of defocused images, we have no reservations whatsoever. The circles of light look nice, with not very high local extremes. It is important that already by f/4.0 the image in the corner of the frame doesn’t differ much from the image in the centre.

Sigma A 60 mm f/2.8 DN - Coma, astigmatism and bokeh