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Lens review

Sigma 150 mm f/2.8 APO EX DG OS HSM Macro

24 August 2011
Szymon Starczewski

7. Coma, astigmatism and bokeh

The crops below show that the coma is not the slightest problem of the tested lens and it is true for the corner of the smaller sensor and for the corner of full frame alike. In a way it was predictable because the excellent image quality on the edge of the frame doesn’t comes from nothing. If the lens had big coma you wouldn’t see a sharp image on the edge of full frame.

Sigma 150 mm f/2.8 APO EX DG OS HSM Macro - Coma, astigmatism and bokeh

The astigmatism is corrected in an equally perfect way. The average difference between vertical and horizontal MTF50 function values amounted to just 2% which is an ideal result.

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The out of focus images of the diode, presented below, are also very nice indeed. The layout of light is very even. What’s more, already by f/5.6 aperture it is difficult to perceive noticeable differences between the diode image in the frame centre and that in the corners of both sensors.

Sigma 150 mm f/2.8 APO EX DG OS HSM Macro - Coma, astigmatism and bokeh