Sigma A 135 mm f/1.8 DG HSM
7. Coma, astigmatism and bokeh
| Center, f/1.8 | Corner APS-C, f/1.8 | Corner FF, f/1.8 |
|
|
|
| Center, f/2.5 | Corner APS-C, f/2.5 | Corner FF, f/2.5 |
|
|
|
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.
Please Support UsIf you enjoy our reviews and articles, and you want us to continue our work please, support our website by donating through PayPal. The funds are going to be used for paying our editorial team, renting servers, and equipping our testing studio; only that way we will be able to continue providing you interesting content for free. |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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 |
|
|
|
| Center, f/2.5 | Corner APS-C, f/2.5 | Corner FF, f/2.5 |
|
|
|
Center, f/3.5 | Corner APS-C, f/3.5 | Corner FF, f/3.5 |
|
|
|
