Overview

The Pentax SMC FA 645 120mm f/4 Macro is a manual-focus lens praised for its smooth, precise focus ring and solid build. Optically, it has no visible distortion and little light falloff, but corners are soft at f/4 and infinity, improving when stopped down. On the GFX 100S, it performs well on-axis at 1:1 but shows soft edges and focus curvature off-axis. It suits macro photographers who prioritize handling and native 1:1 magnification over edge sharpness at wide apertures.