An impressively wide prime lens, the Pentax K-mount 15mm f/2.4 Firefly Lens from Irix meshes an advanced optical design with a lightweight, durable physical construction. The expansive field of view is complemented by a sophisticated optical layout that utilizes low dispersion, aspherical, and high-refractive glass elements, as well as a Neutrino coating, to render imagery with low distortion, controlled spherical and chromatic aberrations, high contrast, and natural color rendering.

In addition to the imaging performance, this 15mm f/2.4 utilizes a manual focus design for fine-tuned control, and incorporates a unique positive focus lock to secure the focusing position at any point for consistent, repeatable shooting. As the Firefly version of this focal length, this lens is also distinguished by a lightweight ABS plastic exterior, printed lens markings, and weather-sealing about the lens housing to permit working in trying environmental conditions.