The maximum focal length lens for general photographic use that could be fitted with acceptable vignetting was 75 mm, although telephotos up to 600 mm were offered. A 150 mm Tele-Xenar was available for long-distance action photography, but it produced a vignetted circular image on the 24 × 24 mm frame. The lack of a rangefinder on the Robot and Robot Star required zone focusing of these long lenses: every shot had to be estimated or premeasured. All of the mechanical movement made for a noisy camera, although not as noisy as some modern motor drives. For an extra fee, Robot-Berning supplied silenced versions with nylon gears.