LensTip.com

Lens review

Sigma C 65 mm f/2 DG DN

27 February 2021
Maciej Latałło

7. Coma, astigmatism and bokeh

Coma and other off-axis aberrations responsible for deformations of point-like images are corrected exceedingly well. The image of a diode put in the frame corner is just slightly enlarged and its shape doesn't give you any reasons to worry. For comparison's sake you can mention the fact that the Sony Carl Zeiss Sonnar T* FE 55 mm f/1.8 ZA, even on stopping down to f/2.5, fared weaker than the Sigma at the maximum relative aperture.

Center, f/2.0 Corner APS-C, f/2.0 Corner FF, f/2.0
Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh
Center, f/2.8 Corner APS-C, f/2.8 Corner FF, f/2.8
Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh


Astigmatism, understood as an average difference between vertical and horizontal MTF50 function values, amounted to 6.1% and it is a slight level. It should be also noticed that the maximum relative aperture contributes the most to that result because by f/2.8 and by f/4.0 that aberration is reduced to practically zero.


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Defocused circles of light look well enough. Light spread in the circles is perhaps not as smooth as in case of fast portrait lenses but it doesn't give us any reasons to complain either. Neither a rim on the edge of the circle nor mechanical vignetting are especially bothersome; that last effect you can notice only in the area closest to the maximum relative aperture.

Center, f/2.0 Corner APS-C, f/2.0 Corner FF, f/2.0
Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh
Center, f/2.8 Corner APS-C, f/2.8 Corner FF, f/2.8
Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh
Center, f/4.0 Corner APS-C, f/4.0 Corner FF, f/4.0
Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh Sigma C 65 mm f/2 DG DN - Coma, astigmatism and bokeh