Irix's budget ultra-wide prime — 15mm f/2.4 with weather sealing in the lighter Firefly build.
The Irix Firefly 15mm f/2.4 is an ultra-wide prime from Swiss-Korean brand Irix, in the lighter Firefly build variant. The 15mm at f/2.4 provides 110° coverage on full-frame — useful for landscape and astrophotography.
Optically good — sharp from f/5.6 with the 15mm providing dramatic ultra-wide perspectives. The f/2.4 is moderate — faster than f/2.8 alternatives but not as fast as f/1.8 options. Weather-sealed construction.
Available for Canon EF and Nikon F mounts. 95mm filter thread — very large. Weather-sealed. The Firefly build uses lighter materials vs the Dragonfly. Electronic contacts for EXIF. Manual focus only. Approximately 570g.
Available used at mid-range prices. Irix is a niche brand but produces genuine quality. The 95mm filter thread is impractical for standard filters. The Samyang 14mm f/2.8 is more popular. For ultra-wide enthusiasts wanting weather-sealed 15mm.