Phil Koenig

 Leica (screw mount / Barnack)

The original Leica.

A landmark design

The original production Leica cameras are known today as the screw mount or Barnack Leicas. They are classics of 20th century industrial design.

The aesthetic value and significance of the screw mount Leica is recognized by the Museum of Modern Art in New York whose collection includes a Leica IIf with a 5cm f/2 Summitar lens — the same body and lens as shown above and right below.

I love these original Leicas. They are as usable today as when they left the factory in Wetzlar, Germany. I’ve made some of my favorite photographs with them.

Why are they called ‘screw mount’ or ‘Barnack’ Leicas?

‘Screw mount’ is a reference to the lens attachment mechanism which is a simple and effective 39mm-diameter screw thread design. It was adopted by other camera manufacturers and became known as the Leica thread mount, LTM, or M39.

‘Barnack’ is a tribute to the camera’s designer, Oskar Barnack.

Leica goes into production

After the war, Leitz decided to develop a camera based on the Ur-Leica. In 1923 a small number of pre-production nullserie (0-series) cameras were made. One is in the collection of the Centre Pompidou in Paris.

After making some design mods, the company began production of the Leica I (model A) in 1924 and it was launched onto the market in 1925. It was a fixed lens, scale-focusing camera with a focal plane shutter.

• This was ‘the first 35 mm camera to be successfully mass-produced with a 35 mm cinema film format’ (Leica Camera).

There was also a Leica I (model B) of which few were made; it substituted a Compur leaf shutter for the focal plane shutter.

The Leica I (model C) was introduced in 1931 (Rogliatti, 1995:49; some other sources say 1930). It was a model A with the addition of an interchangeable lens mount — the first Barnack-type Leica with the screw mount.

Leica takes off

Closely following the introduction of the Leica I (model C), the 1932 Leica II (model D) added a rangefinder. This established the essential screw mount Leica paradigm and it was at about this time (1931-32) that Cartier-Bresson purchased his first Leica (source: Fondation Henri Cartier-Bresson, Paris).

1933 was the start of Leica III production. It added slow speeds selected using a dial on the front of the camera. The later Leica II models were essentially Leica IIIs with the slow speed dial deleted and a cover patch in its place.

A long production run

Design updates were done through the 1930s, 40s, and 50s. The top shutter speed went from 1/500 to 1/1000, shutter speed intervals were changed, flash synch was added, body structure part-count was reduced, and so on.

Leitz continued to invest in the Leica screw-mount product line even after the introduction of the new bayonet mount M3 in 1954. The last screw-mount Leica was delivered in 1960.

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Leica history information is from Rogliatti 1985, Matanle 1986, Gustavson 2011, Leica Photographic Equipment, Catalog No. 35, and museum websites (see References).

Imitation is the sincerest form of flattery

Copies of the screw mount Leica hit the market starting just two years after the introduction of the Leica II when, in 1934, the FED factory in Ukraine, USSR began mass production of the FED-1. (See the Zarya article for that story).

I have not seen any reference to patent licensing; perhaps the Soviet Union in the 1930s was beyond the jurisdiction of the German patent office?

Then, in the aftermath of World War II, Leitz designs were copied wholesale by many others. Japanese, Chinese, British, American, and perhaps more screw mount Leica clones hit the market. Examples are in Gustavson 2011, McKeown 1996, and St. Denny 1989.

Screw mount Leicas are super compact

One of the big advantages of the screw mount Leica is that it is really small. Both the camera body and the lenses are tiny.. For openers, they are not SLRs so:

• There isn’t a mirror box in the body.

• The lenses don’t need an auto aperture mechanism.

And furthermore::

• There is no rear door for film loading and unloading.

• No light meter.

• Some lenses can fold into the body when not in use.

Viewfinder and rangefinder - Each with its own window

The Leica II and subsequent screw mount Leicas have separate viewing windows for the rangefinder and viewfinder. Some find this inconvenient, but there’s an advantage. Because the rangefinder is not used for framing. it has higher magnification and that helps with focusing.

Film loading

It’s not done the usual way. There is no rear door, nor does the back of the camera come off. Access is only from the bottom. Here’s the general idea:

1. Remove the bottom of the camera. There’s a drawing inside, showing how the film leader is to be trimmed. Leica made a template, but it’s not necessary and I don’t have one. I use a pair of scissors and follow the drawing.

2. Remove the take-up spool and insert the trimmed film leader.

3. Insert the film canister + film leader + take-up spool assembly into the camera, upward from the bottom.

4. Put the camera bottom back in place, and wind the film on, while checking the rewind knob to make sure that the film leader is properly attached to the take-up spool.

5. Manually reset the film frame counter.

There is a detailed, illustrated, step-by-step set of instructions for this in Emanual (1957). It’s a finicky process but after a few rolls of film it becomes second nature.

Loading from the bottom does have advantages:

1. Lack of a door or removable back makes the camera body stronger. No camera I’ve used, not even the Leica M3, has the solidity of a screw-mount Leica.

2. The bottom plate attaches to the body with a precise metal-to-metal fit. No need for the foam light seals used in the film doors of many 35mm cameras.

The screw mount Leica in use

Screw mount Leicas are among my top favorite cameras. They are small, have an unmatched smooth and precise feel, and some of the greatest photographs of the 20th century were made with them.

A disadvantage of the compact design is that the rangefinder and viewfinder are small, so composition and focus are not as quick and accurate as with, say, an M-series Leica or a Japanese SLR. Also, film advance and film loading/unloading are not so quick. And, these are very old cameras that may require servicing (see below).

Compatible lenses from other manufacturers

Lately, I’ve been occasionally experimenting with Japanese Leica thread mount (LTM) lenses on my Leicas. With Leitz lenses increasingly difficult to find in good condition, high-quality lenses made by others are an attractive option.

Canon made LTM rangefinder cameras and lenses into the 1960s. Nikon’s rangefinder cameras did not use the LTM mount, but the company made LTM Nikkor lenses that were supplied with Nicca cameras.

LTM lenses were made by other Japanese companies. Examples include Chiyoda Kogaku (later renamed Minolta), Tokyo Kogaku, and Fujinon. LTM lenses were also made in the Soviet Union.

Maintenance and repair

The shutter curtains of my Leica IIIa were replaced in the late 1990s by Penn Camera in Rockville, Maryland (which is no longer in business).

In 2025 my Leica IIIc was given a thorough overhaul by YYe Camera in Canton, Massachusetts. That included a new rangefinder beam splitter which improved rangefinder visibility quite a lot.

References / further reading

Camera manual: orphancameras.com

More references:

Cartier-Bresson, H. 1999. The Mind’s Eye: Writings on Photography and Photographers. New York: Aperture. Writings by the master of the ‘decisive moment’.

Cartier-Bresson, H. 1976. Henri Cartier-Bresson. New York: Aperture Foundation. Masters of Photography series. 95 pages of photography and text by Cartier-Bresson.

Centre Pompidou, Paris. The collection includes a pre-production 0-series Leica from 1923. https://www.centrepompidou.fr/en/ressources/oeuvre/c4b9dzK accessed Aug. 31, 2025.

Emanuel, W.D. 1957. Leica Guide: How to Work With All Leica Models From I to M3. New York: American Photographic Book Publishing Co., Inc.

Film loading is explained step-by-step, with illustrations, on pp. 13-15.

Fondation Henri Cartier-Bresson. https://www.henricartierbresson.org/en/hcb/biography/

Gustavson, T. 2011. 500 Cameras: 170 Years of Photographic Innovation. New York: Fall River Press.

The 500 cameras are from the George Eastman House Technology Collection, Rochester, N.Y. Multiple screw mount Leicas and Leica copies are described..

Instructions for Models — Standard, IIIa & 250 and Accessories.. n.d. Ernst Leitz, Wetzlar and London. Hove Camera Company reprint, Hove, Sussex, England. n.d.

Leica Camera. From Vision to Legend: The History of the Leica I. https://leica-camera.com/en-US/photography/100-years/the-history-of-the-leica-I accessed Oct. 7, 2025.

Leica Photographic Equipment, Catalog No. 35. 1960. E. New York: Leitz Inc.

List of retro-style digital cameras. n.d. https://en.wikipedia.org/wiki/List_of_retro-style_digital_cameras accessed Nov. 5, 2025.

‘These cameras are designed to resemble and are often mistaken for vintage film cameras’.

McKeown, J.M. and J.C. 1996. McKeown’s Price Guide to Antique and Classic Cameras, 1997-1998. Grantsburg, Wis.: Centennial Photo.

Has 14 pages on Leitz/Leica cameras and lenses, including a tabular guide to identification of the different models (p. 292) and a list of Leica serial numbers (pp. 293-297).

Matanle, I. 1986. Collecting and Using Classic Cameras. London: Thames and Hudson.

Morgan, W.D. and H.M. Lester. 1956. Leica Manual and Data Book. New York: Morgan & Morgan.

Museum of Modern Art, New York. The collection includes a Leica IIf. Architecture and Design Department, Object number 1271.2018.a-c https://www.moma.org/collection/works/292758 accessed Aug. 31, 2025.

National Museum of American History, Smithsonian Institution. The collection includes a Leica I (model C). https://americanhistory.si.edu/collections/object/nmah_1145349 accessed Aug. 31, 2025.

Pritchard, M. 2015. A History of Photography in 50 Cameras. Buffalo, N.Y.: Firefly Books. The Leica I is camera no. 20.

Rogliatti, G. 1985. Leica: The First 70 Years. East Sussex, England: Hove.

Smithsonian Institution, National Museum of American History, Washington, D.C. The collection includes a working Ur-Leica replica made by Leitz. https://americanhistory.si.edu/collections/object/nmah_1145586

St. Denny, D. 1989. Cameras of the People’s Republic of China. Leicester, England: Jessop Specialist Publishing.

pp. 75-78: The Shanghai Camera Factory made screw mount Leica copies from 1958 to 1963.