The Irix Firefly 15 mm f/2.4 is a slim Nikon prime that opens to 76.8° vertical, letting you frame wide interiors or sweeping landscapes with crisp detail from just 0.25 m. Its manual focus ring and nine‑blade diaphragm give tactile control and smooth bokeh at wide apertures, while two aspheric elements keep distortion low for clean architectural lines. The lightweight metal body and 95 mm filter thread make it a versatile companion for full‑frame DSLRs.