Lens review

Sigma 19 mm f/2.8 EX DN

5. Chromatic and spherical aberration

In the resolution category the Sigma 2.8/19 fared worse than the 2.8/30 model but the lateral chromatic aberration is quite another story – the tested lens fares better here. This aberration depends weakly on the aperture value and in the whole range it keeps near 0.08% which we consider as a not very bothersome level.

These results are, at the same time, comparable to the performance of the Panasonic 1.7/20 and significantly better than those presented by the Olympus 2.8/17.

It can be noticed that defocused diode images differ from each other significantly which proves the spherical aberration is not corrected in a perfect way. In both cases we see lighter and darker rims; apart from that the image in front of the focus has a distinctly lighter shade in the middle of the circle than the image behind the focus.