Overview

The Irix 11mm f/4 is the widest rectilinear full-frame lens, offering a 126° diagonal view with straight lines. Optically, it is sharp but exhibits lateral chromatic aberration that may require correction, especially on Canon cameras. Build quality is robust, with the Blackstone version being metal and weather-sealed, while the Firefly is lighter and plastic but optically identical. It is manual focus with electronic contacts for EXIF and aperture control. The fixed hood prevents screw-on filters; rear gel filters are available but finicky. It suits landscape and creative photographers seeking an ultra-wide perspective on a budget, but not for astrophotography due to f/4.