LensTip.com

Lens review

Sigma A 12-24 mm f/4 DG HSM

23 October 2016
Arkadiusz Olech

7. Coma, astigmatism and bokeh

The Sigma A 12–24 mm f/4 DG HSM corrects the coma quite well. We didn’t observe any problems in the corners of the APS-C/DX sensor; in the corners of full frame you could notice slight deformation of the diode but it was nothing to be worried about. Such results are similar to those from the Canon 11-24 mm and noticeably better than those of the darker predecessor of the Sigma.

Center, 12 mm, f/4.0 Corner APS-C, 12 mm, f/4.0 Corner FF, 12 mm, f/4.0
Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh
Center, 18 mm, f/4.0 Corner APS-C, 18 mm, f/4.0 Corner FF, 18 mm, f/4.0
Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh
Center, 24 mm, f/4.0 Corner APS-C, 24 mm, f/4.0 Corner FF, 24 mm, f/4.0
Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh


When it comes to the astigmatism understood as an average difference between horizontal and vertical MTF50 function values, it amounted to 3.2%. The results below 5% we consider to be low so it seems the Sigma 12-24 mm corrects that off-axis aberration very well; anyway its result is a tad better than the result of the more expensive Canon 11-24 mm.


Please Support Us

The coronavirus crisis has been adversely affecting many businesses and, sad but true, ours is not an exception. Despite that difficult situation we would like to preserve continuity and high quality of publications available on all our websites. Still, we are now aware it might be impossible without additional financial help. That's why we would like to ask all those who visit, read, and care about Optyczne.pl, LensTip.com i Allbinos.com for support - it's enough you send us a small sum of money via PayPal. If a lot people decide to support our websites we think we'll stand a chance and survive next months without any lasting harm. We count on your support and understanding, stay safe and be healthy.

- - - - - - - - - - - - - - - - - advertisement - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

With such a focal range and aperture values it is very difficult to get big out-of-focus areas in photos so appraising the lens in this category is a bit art for art’s sake. Still it’s worth noticing that defocused circles of light look sensible; their only flaw is a lighter rim. What’s important, there are no traces of distinct mechanical vignetting.

Center, 24 mm, f/4.0 Corner APS-C, 24 mm, f/4.0 Corner FF, 24 mm, f/4.0
Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh
Center, 24 mm, f/5.6 Corner APS-C, 24 mm, f/5.6 Corner FF, 24 mm, f/5.6
Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh
Center, 24 mm, f/8.0 Corner APS-C, 24 mm, f/8.0 Corner FF, 24 mm, f/8.0
Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh Sigma A 12-24 mm f/4 DG HSM - Coma, astigmatism and bokeh