SOM Berthiot Angulor 28mm f/3.3

SOM Berthiot Angulor 28mm f/3.3

The SOM Berthiot Angulor 28mm f/3.3 is a rare French wide-angle rangefinder lens from the early 1950s. Original factory versions are documented for both Leica thread and Contax RF cameras.

Both known mount versions are rangefinder coupled and use dedicated focusing barrels. No material optical difference has been demonstrated, so they belong in one profile without a mount suffix. In Leica Lens List taxonomy, the Leica screw version should be classified as LTM rather than generic M39.

Published descriptions conflict over whether the lens contains six elements in four groups or six elements in six groups. Until factory documentation or a reliable optical diagram resolves this conflict, both fields should remain Unknown.

Optical qualities

Rendering

Reliable controlled optical information is limited. The lens should therefore be described conservatively as a compact period wide-angle without assigning a specific rendering signature based on the disputed optical formula.

As with other early wide-angle rangefinder lenses, condition, internal haze and alignment may influence present-day results as much as the original design.

History

Development and Launch

The Angulor appeared around 1950, when SOM Berthiot was offering specialist lenses for several European camera systems.

Production Evolution

Documented examples show both LTM and original Contax RF barrels during the 1950s.

Special Editions and Variants

Mount and engraving differences should remain within one profile unless a distinct optical construction is demonstrated.

Collector Notes

Confirm that the rangefinder mechanism operates correctly and that the rear optics are free from haze or separation.