Angénieux Retrofocus Type R1 35mm f/2.5

Angénieux Retrofocus Type R1 35mm f/2.5

The Angénieux Retrofocus Type R1 35mm f/2.5 is a French manual-focus wide-angle designed by Pierre Angénieux and introduced in 1950. Its six-element, five-group reverse-telephoto formula places a negative front meniscus well ahead of a positive rear section. This creates substantially more rear clearance than a conventional symmetrical wide-angle. Angénieux's patent describes a 65-degree f/2.5 example that corresponds to the original Type R1 concept.

For LeicaLensList, the original rangefinder versions in coupled Leica Thread Mount and factory Contax RF mount belong to one profile. Leitz Photographica Auction documents both as genuine factory lenses from around 1950, while a second coupled LTM example is dated 1952. They share the Type R1 optical identity and do not require mount suffixes in the model name. The more common Exakta and other SLR-mount versions are outside this rangefinder profile, and later conversions must not be mistaken for factory LTM production.

The lens is manually focused and uses a manual iris. KEH identifies a 52mm filter size for the Leica screw-mount version. Reliable rangefinder-specific figures for overall dimensions, weight, minimum focusing distance and diaphragm blade count have not been established, so SLR-version specifications should not be copied into this profile.

Optical qualities

Rendering

The strongly asymmetric 6/5 layout is the defining optical feature. Its separated negative front element increases back focus and supports better peripheral illumination, while the positive rear section forms the image. Angénieux's patent specifically addresses correction of distortion, coma and astigmatism, together with reduced vignetting at a relatively wide aperture.

These patent statements describe design goals rather than modern measured performance. Reliable mount-specific MTF or bench data for the original LTM and Contax RF versions is limited. Coating condition, haze, cleaning marks and previous servicing can therefore have a large influence on contrast, flare and edge performance in surviving examples.

History

Development and Launch

Pierre Angénieux filed the underlying French priority application on 17 February 1950 and the corresponding United States application on 29 July 1950. The official Angénieux history identifies the 35mm f/2.5 R1 as the first Angénieux Retrofocus lens. The Retrofocus name became closely associated with the reverse-telephoto wide-angle principle.

Production Evolution

Original factory rangefinder examples are documented in both coupled LTM and Contax RF mount from 1950. A coupled LTM lens dated 1952 and scaled in feet confirms continued early production and an engraving variation. Angénieux reports more than 50,000 R1 lenses sold overall, but that figure covers the broader model family and does not establish production totals for either rangefinder mount. A reliable final production year for the rangefinder versions has not been established.

Special Editions/Variants

No separately catalogued special edition is confirmed. Factory LTM and Contax RF mounts, together with distance-scale and engraving variations, are production variants within this Type R1 profile rather than separate optical models.

Collector Notes

Verify that a rangefinder example retains an original factory mount, focusing assembly and coupling mechanism. Type R1 lenses are much more frequently encountered in SLR mounts, and later conversions exist. Barrel condition and optical haze are especially important because they can materially affect use, while the presence of an original LTM or Contax RF assembly strongly affects collector identity.