Sigma A 70 mm f/2.8 DG Macro
5. Chromatic and spherical aberration
Chromatic aberration
The Sigma A 70 mm f/2.8 DG Macro features as many as four low dispersion elements. It seems they perform as they should because the lens doesn’t have any problems concerning the longitudinal chromatic aberration. Photos below show that it would be difficult to find any traces of it even in areas situated far from the depth of field. |
The lateral chromatic aberration correction is as good; the graph below presents the lens’s performance depending on the aperture and the position in the frame.
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Most of results are within 0.02- 0.03% range; it means you deal here with very low values and the aberration won’t bother you practically at all.
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| Canon 5D III, RAW, f/2.8 | Canon 5D III, RAW, f/4.0 |
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Spherical aberration
First photos of this chapter don’t show any ‘focus shift’ effect. As you see in crops below, circles we got in front of and behind the focus are very similar. The only difference between them is visible on the edge – in the case of one of these circles you can notice a slight rim. These facts suggest the tested lens doesn’t have any noticeable problems with spherical aberration correction.
| Canon 5D III, f/2.8, in front of | Canon 5D III, f/2.8, behind |
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