Irix 15mm f/2.4 Review

May 4, 2017 | Mark Goldstein |

Irix 15mm f/2.4 Sharpness at 15mm

Our sharpness tests were conducted using a 42-megapixel Canon EOS 5DS R body mounted to a tripod. The camera’s shutter release was also set on a timer-delay to avoid any possible camera shake. The test subject was shot using ambient lighting, hence some colour and contrast variation is to be expected between apertures.

The full frame at 15mmThe full frame at 15mm

Centre sharpness is impressively high throughout the entire aperture range, with peak performance between f/4-f/11. Corner sharpness is also very good, again producing optimal sharpness at f/4-f/11. At f/16 sharpness is beginning to drop off a little due to diffraction, and is clearly evident at f/22.

Aperture Centre Crop Edge Crop
f/2.4 f2_4.jpg f2_4.jpg
f/2.8 f2_8.jpg f2_8.jpg
f/4 f4.jpg f4.jpg
f/5.6 f5_6.jpg f5_6.jpg
f/8 f8.jpg f8.jpg
f/11 f11.jpg f11.jpg
f/16 f16.jpg f16.jpg
f/22 f22.jpg f22.jpg