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Lens review

Irix 15 mm f/2.4 Blackstone

27 September 2016
Szymon Starczewski

9. Ghosting and flares

Ultra wide-angle lenses designed for full frame are very complex optical constructions usually featuring big front elements; as you can imagine, fighting ghosting and flares is not an easy task in their case. However, the situation of the Irix 2.4/15 attached to the 5D Mark III near the maximum relative aperture doesn’t look too bad – it’s enough to look at photos below.

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

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Irix 15 mm f/2.4 Blackstone - Ghosting and flares


Still it’s difficult not to have an impression that high vignetting levels help fighting flares by damping down the brightness of images in the corners and quenching light artefacts. Let’s check how the flares look on stopping down.

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares


According to our expectations the situation is not exactly rosy. The flares are distinct, they appear in different combinations of settings and often they are able to spoil the frame completely.

It’s worth noticing that by f/8.0 the vignetting level of the Irix remains noticeable what was shown in the previous chapter so it still helps fighting the flares. It’s worth checking the situation on the smaller sensor of the Canon 50D where the vignetting can no longer help the lens with that aberration.

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares


This time you have no problems whatsoever with noticing light artifacts- either near the maximum relative aperture or on more significant stopping down.

Finally you should mention one more thing. Most of 14-15 mm lenses present on the market have in-built hoods. The Irix features a removable hood. If you want to be fair and compare it to, say, the Samyang 2.8/14 you should test it with the hood attached. Let’s glance at photos below to see the results.

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares

Irix 15 mm f/2.4 Blackstone - Ghosting and flares


There are perhaps some differences but they remain slight. To sum up, even after attaching the hood you cannot avoid noticeable light artefacts while working against bright light.