LensTip.com

Lens review

Sigma A 135 mm f/1.8 DG HSM

14 April 2017
Maciej Latałło

7. Coma, astigmatism and bokeh

The Sigma A 1.8/135 corrects coma in a splendid way. Even in the corners of full frame the images of a diode are deformation-free. Still it must be clearly said that the rivals of the Sigma such as the Canon, the Samyang and the Zeiss, performed equally well in this category.

Center, f/1.8 Corner APS-C, f/1.8 Corner FF, f/1.8
Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh
Center, f/2.5 Corner APS-C, f/2.5 Corner FF, f/2.5
Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh


The astigmatism, understood as an average difference between horizontal and vertical MTF50 function values, amounted to 4.9%. That value is slight but still officially the highest in the group of all 2/135 lenses, mentioned in this test. It’s worth remembering, though, that the results of the Samyang and the Zeiss, amounting to 3.5-3.8% are, within margin of error, interlocking with the result of the Sigma.

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

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

When it comes to the appearance of out-of-focus areas we have almost no reservations. The light spread in them is very even, without any distinct rims of local extremes. Even the ring on the very edge is not especially accented. Still a truncation of circles, connected to mechanical vignetting, is clearly visible, even though it seems to be a bit less pronounced than in the case of the slower Zeiss or the Samyang.

Center, f/1.8 Corner APS-C, f/1.8 Corner FF, f/1.8
Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh
Center, f/2.5 Corner APS-C, f/2.5 Corner FF, f/2.5
Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh
Center, f/3.5 Corner APS-C, f/3.5 Corner FF, f/3.5
Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh Sigma A 135 mm f/1.8 DG HSM - Coma, astigmatism and bokeh