Carl Zeiss Jena Biotar 75mm f/1.5

Carl Zeiss Jena Biotar 75mm f/1.5

The Carl Zeiss Jena Biotar 75mm f/1.5 is a rare post-war portrait lens documented in an original, rangefinder-coupled Leica thread mount. Its six-element, four-group design and eighteen-blade iris sit in a substantial chrome barrel.

Optical qualities

Rendering

The Biotar’s six-element, four-group double-Gauss construction is known for strong central definition, pronounced subject separation and energetic out-of-focus rendering at wider apertures. Stopping down increases contrast and edge consistency, while the eighteen-blade diaphragm maintains a nearly circular opening.

Handling

The coupled LTM version focuses to approximately 1 m according to dedicated rangefinder-lens references. Its bright f/1.5 aperture aids focusing, but the large front section and substantial metal barrel make it heavier than a typical screw-mount normal lens. A verified filter specification is not entered.

History

Development and Launch

The Biotar 75mm f/1.5 originated before the war, but the documented coated Leica M39 version dates from 1949. It belongs to the post-war slim generation produced by Carl Zeiss Jena.

Production Evolution

Post-war examples retained the chrome construction and eighteen-blade diaphragm while adding T coating. Later SLR versions adopted different barrels, focusing distances and, eventually, fewer aperture blades.

Special Editions/Variants

The LTM version is a scarce factory mounting rather than a generic adaptation of the common Exakta or M42 lens. Coating marks and engraving details vary across production.

Collector Notes

Original coupled LTM construction is essential for identification. The large chrome barrel, T marking and smooth operation of the many-bladed diaphragm are important checks when assessing a surviving example.