Carl Zeiss Biotar 5cm f/1.4 (Rangefinder-Coupled)

The Carl Zeiss Jena Biotar 5cm f/1.4 profiled here is the original rangefinder-coupled Leica M39 version, not a modern cine-lens conversion. A surviving black example, serial number 1365672, dates from 1932 and has a feet scale, original hood and a 1.5-foot minimum-focus marking. A later silver example, serial number 2375379, dates from 1938; according to the auction description citing Thiele, it belonged to a series of only 46 lenses and was the first of the very small number supplied with Zeiss T coating.

Optically, it uses Willy Merté’s six-element, four-group asymmetrical Double-Gauss design for the full 24×36mm Leica format. Early examples are uncoated and can show low contrast, flare, glow, field curvature and soft corners at f/1.4. Stopping down improves clarity considerably. Original coupling hardware, barrel construction, serial number and finish are essential for identification because numerous cine and industrial Biotars have subsequently been converted to Leica mounts.