LensTip.com

Lens review

Irix 15 mm f/2.4 Blackstone

27 September 2016
Szymon Starczewski

5. Chromatic and spherical aberration

Chromatic aberration

The photos below prove that the Irix has no problems whatsoever with perfect correction of the longitudinal chromatic aberration.

Irix 15 mm f/2.4 Blackstone - Chromatic and spherical aberration

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We have no reservations concerning the correction of the lateral version of that aberration and the graph below shows why.

Irix 15 mm f/2.4 Blackstone - Chromatic and spherical aberration


Most of the results are hovering around 0.03–0.06% which we consider low or very low levels. Here the Irix 2.4/15 fares a bit better than the Samyang which maximum aberration results could get to 0.13%.

Canon 5D III, f/2.5 Canon 5D III, f/8.0
Irix 15 mm f/2.4 Blackstone - Chromatic and spherical aberration Irix 15 mm f/2.4 Blackstone - Chromatic and spherical aberration



Spherical aberration

First photos of this chapter don’t show any „focus shift” effect so the spherical aberration cannot be especially high. Out-of-focus circles of light aren’t able to shed more light on that issue because they are simply too small. Still, as we didn’t notice huge differences between them we assume that the tested lens doesn’t have distinct problems in the area of spherical aberration.

Canon 5D III, f/2.5, in front of Canon 5D III, f/2.5, behind
Irix 15 mm f/2.4 Blackstone - Chromatic and spherical aberration Irix 15 mm f/2.4 Blackstone - Chromatic and spherical aberration