SOM Berthiot

Est. 1857

SOM Berthiot

SOM Berthiot, also written S.O.M. Berthiot, was a major French optical manufacturer whose origins trace to the photographic lens workshop established by Claude Berthiot in Paris in 1857. The initials SOM represented Société d’Optique et de Mécanique de Haute Précision, a company name adopted in 1913.

The manufacturer produced photographic lenses, cinema lenses, projection optics, military equipment, surveying instruments, and other precision optical products. For Leica rangefinder camera users and vintage photography equipment collectors, SOM Berthiot is particularly associated with a small range of Leica Thread Mount lenses. These included the rare Angulor 28mm f/3.3 wide-angle lens, along with Flor and Télé models in longer focal lengths.

The original Angulor 28mm f/3.3 was available in a rangefinder-coupled M39 Leica screw mount, commonly called LTM. It was not a native Leica M-mount lens, although an original LTM example can be fitted to many Leica M cameras using an appropriate LTM-to-M adapter.

History

Founding / Early Years

Claude-Stanislas Berthiot established a photographic lens workshop in Paris in 1857. His nephew, Eugène Lacour, joined the business in 1884 and assumed control in 1894. The company subsequently traded as Lacour-Berthiot and was incorporated as Établissements Lacour-Berthiot S.A. in 1908.

Berthiot and Lacour developed photographic objectives during a period of rapid progress in optical glass, anastigmatic correction, and camera design. Early product names included Périgraphe and Eurygraphe, with later lens families covering portrait, general-purpose, wide-angle, and technical photography.

Market Entry

Photographic optics were the company’s original business rather than a later diversification. In 1913, following investment by Schneider et Cie, the company adopted the name Société d’Optique et de Mécanique de Haute Précision. Products made after this transition were commonly marked SOM Berthiot.

SOM expanded beyond camera lenses into precision instruments such as optical rangefinders, periscopes, measuring devices, and military optics. In 1934, it acquired Fleury-Hermagis and its manufacturing facilities in Dijon. The acquisition strengthened SOM Berthiot’s position in French optical manufacturing and provided additional capacity for photographic and cinematographic products.

During the postwar period, SOM Berthiot offered lenses for French cameras, Exakta cameras, Leica screw-mount rangefinder cameras, and other systems. The rangefinder-coupled Angulor 28mm f/3.3 appeared during the early 1950s. Original M39 examples are documented, as are rare versions for the Contax rangefinder outer bayonet mount.

Expansion / Modern Period

SOM Berthiot became especially prominent in cinematography. In 1949, company engineer Roger Cuvillier developed the optical-compensation system associated with the Pan-Cinor. Commercial Pan-Cinor zoom lenses followed in the early 1950s and became an important part of the company’s cinema equipment business.

The manufacturer also continued producing still-camera lenses, projection lenses, photogrammetric equipment, topographic instruments, and specialized industrial and military optics. Its operations included facilities in Paris and Dijon, and the company employed more than one thousand people during its postwar expansion.

In 1965, SOM merged with Optique et Précision de Levallois, the manufacturer associated with Foca cameras, to form SOPELEM. The successor organization later became connected with SFIM and was ultimately absorbed into Sagem around 1999 to 2000. SOM Berthiot therefore no longer survives as an independent photographic lens manufacturer.

Product Lines

Leica Thread Mount Rangefinder Lenses

SOM Berthiot produced a limited selection of rangefinder-coupled Leica screw-mount lenses. Documented examples include the Angulor 28mm f/3.3, Flor 35mm f/3.5, Flor 50mm f/2.8, Flor 50mm f/1.5, Flor 75mm f/2.8, Flor 90mm f/2.8, and Télé 145mm f/4.5.

These lenses use the M39 Leica Thread Mount rather than the later Leica M bayonet. Compatible examples can be adapted to Leica M-mount cameras, although correct rangefinder operation depends on the lens, adapter, and mechanical condition.

Angulor Wide-Angle Lenses

The Angulor 28mm f/3.3 is the SOM Berthiot lens most directly relevant to LeicaLensList. Contemporary catalog information describes it as a six-element wide-angle lens, while surviving auction examples confirm original rangefinder-coupled M39 production.

An original Contax rangefinder version is also documented. Because Angulor lenses can appear in different mounts and configurations, the mount, rangefinder coupling, and factory engravings should be inspected rather than inferred from the model name alone.

Flor and Télé Lenses

Flor was used for several normal, fast, and short telephoto lenses across multiple camera systems and formats. SOM Berthiot also used the Télé designation for longer focal-length lenses. Optical construction varied by model, with documented Flor designs containing four, six, or seven elements.

Cinor and Pan-Cinor Cinema Lenses

Cinor was a major SOM Berthiot cinema-lens family, covering several motion-picture formats and focal lengths. Pan-Cinor identified the company’s variable-focal-length cinema lenses, including models with integrated viewing systems. These products form an important part of the history of early practical zoom-lens development.

Large-Format, Projection, and Instrument Optics

SOM Berthiot and its predecessors manufactured large-format photographic lenses under names including Périgraphe, Eurygraphe, Stellor, and Olor. The company also produced projection lenses, enlarging optics, photogrammetric equipment, surveying instruments, ophthalmic devices, and military optical equipment.

Technical Characteristics

Feature	Description
Manufacturer identity	French optical manufacturer known as Claude Berthiot, Lacour-Berthiot, Établissements Lacour-Berthiot, and later SOM Berthiot.
Reference lens	SOM Berthiot Angulor 28mm f/3.3, a compact wide-angle lens produced during the early 1950s.
Optical construction	Period lens listings describe the Angulor 28mm f/3.3 as a six-element design.
Original Leica mount	M39 Leica screw mount, also known as Leica Thread Mount or LTM.
Rangefinder coupling	Documented original M39 examples are mechanically coupled to the camera rangefinder.
Other documented mount	A rare factory Contax rangefinder outer-bayonet version is known.
Leica M compatibility	Not a native M-mount lens. An original LTM example can be mounted using a suitable LTM-to-M adapter.
Viewfinder requirements	Most Leica screw-mount cameras lack built-in 28mm framing, making an external 28mm finder advisable. Frameline availability on Leica M cameras depends on the camera body and adapter.
Focusing	Manual focus, with mechanical rangefinder coupling on documented original rangefinder versions.
Lens coating	Coated surviving examples are documented, although coatings and cosmetic details may differ between production batches.
Construction	Period examples use compact metal barrels with engraved distance and aperture scales. Condition varies substantially because of age and previous servicing.
Identification	Authenticity should be assessed using the front-ring engraving, serial number, mount construction, rangefinder cam, and evidence of later conversion or rehousing.
Brand distinction	SOM Berthiot should not be confused with Benoist-Berthiot, a separate French optical company with no corporate connection to Claude Berthiot’s firm.

Market Reception

SOM Berthiot is regarded as an important name in French optical manufacturing, particularly for its combination of photographic lenses, cinema optics, and precision instruments. Its Leica Thread Mount lenses were produced in much smaller quantities than contemporary Leica, Canon, or Nikon rangefinder lenses, making surviving examples relatively uncommon.

The Angulor 28mm f/3.3 is especially sought after as a rare original French LTM wide-angle lens. Collector interest is influenced by the originality of the M39 mount, functional rangefinder coupling, optical condition, serial number, and the presence of original caps or accessories. Converted or rehoused Angulor lenses may differ mechanically from factory-produced rangefinder versions.

For practical photography, an original LTM Angulor can be used on compatible Leica screw-mount cameras, adapted Leica M cameras, and many mirrorless digital cameras. As with other vintage camera lenses, sample condition, haze, fungus, cleaning marks, lubrication, and previous repairs can have a significant effect on usability and image quality.

Sources

Lenses (3)

Make	Model	Price	Focal Length	Aperture	Release year	Diameter (mm)	Length (mm)	Weight (g)	Min focus distance	Elements	Groups	Filter diameter (mm)	Mount	Model number(s)
SOM Berthiot	Angulor 28mm f/3.3	.	28	3.3	1950	Unknown	Unknown	0 g	Unknown	Unknown	Unknown	Unknown	LTM / Contax RF	Angulor 1:3.3 F=28mm, Angulor 3.3/28
SOM Berthiot	Flor 55mm f/1.5	.	55	1.5	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	LTM	Unknown
SOM Berthiot	Flor 50mm f/1.5	.	50	1.5	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	LTM	Unknown