Overview

The Optomax 400mm f/6.3 is a vintage manual-focus telephoto lens that delivers surprisingly good image quality for its price, especially for static subjects like the moon. Optical performance is decent even with a teleconverter, though focusing on fast-moving birds is challenging (spiralcity). Build is typical of 1960s M42 lenses, requiring an adapter for modern cameras and full manual operation. It suits photographers interested in retro gear or budget telephoto work for slow or stationary subjects.