Overview

The NiSi 15mm F4 is a compact, all-metal manual lens with a 14.5mm effective field of view and 72mm filter thread. Its standout feature is ten straight aperture blades producing clean sunstars at any aperture. Optical strengths include good sharpness at f/8, low distortion, and decent flare resistance. Weaknesses: significant vignetting (2.3 EV wide open), corner softness, and focus creep. It suits landscape and real-estate photographers wanting an affordable ultra-wide with unique sunstar capability.