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LEICA I MODEL B

The Leica I Model B, introduced in 1926, was notable for its incorporation of a Compur shutter situated between the lens elements38. Unlike the Leica I Model A, the Leica I Model B was equipped with a small round shutter, known as the Compur shutter, built into the lens instead of a focal plane shutter and a film/shutter coupling mechanism360. The design prioritized film transport over the interlocking shutter-cocking with film winding found in other models, leading to the potential for unintended double exposures159. Shutter operation was handled via Compur levers on the lens, with settings for shutter speed and aperture controlled through a dial mechanism159. Additionally, the lens's front diameter was unique, necessitating specialized filters159. According to Leitz New York Pamphlet No. 1098 from January 1927, this camera catered to photographers seeking a more economical alternative to the higher-priced models equipped with focal plane shutters17.

One of the main reasons for introducing this camera was believed to be the lack of slow shutter speeds in the Leica I Model A360. To address this issue, the Leica I Model B was designed with a Compur shutter to meet the demand for these slower speeds360. Lenses with moderate maximum apertures, combined with very slow emulsions (such as 12 ASA), often required shutter speeds between 1/25th of a second and B/T, which could be achieved with the Compur shutter360.

This model was released in two variations: the initial production featured a dial-set shutter mechanism, whereas subsequent versions adopted a rim-set design38. Both dial-set and rim-set models came with a non-interchangeable Compur-shuttered360 50mm f/3.5 Elmar lens mounted in a collapsible housing38. Film transport and shutter reset mechanisms were separate; therefore, the camera had a dedicated large frame counter replacing the traditional shutter-speed dial38. Notably, the standard shutter release was substituted with a sprocket release device, which allowed for sequential film advancement but omitted a double-exposure prevention mechanism38. The shutter speeds ranged from a minimum of 1/10 of a second to maximum speeds of 1/300 of a second, with intermediate settings including 1/5, 1/2, and 1-second exposures38.

Code name for the Leica I Model B with one magazine was LECUR, and LECOM for Leica I Model B with one magazine plus solid leather case with handle534. 

In 1930, there were 609 Leica I Model B cameras delivered364. In 1931, there were 81 Leica I Model B cameras delivered364. In 1932, there were 6 Leica I Model B cameras delivered364. In 1934, there were 2 Leica I Model B cameras delivered364. In 1938, there was 1 Leica I Model B camera delivered364. In 1939, there was 1 Leica I Model B camera delivered364. 1941 marked the last year for the deliveries of Leica I Model B, with 16 cameras delivered364.


Leica I Model B Dial-Set Compur

This was the first model of the Leica I Model B, introduced in 1926360. It featured two dials on the face: the first dial set the shutter speeds ranging from 1 second to 1/300th of a second, while the second, smaller dial selected the exposure mode: instantaneous (I), bulb (B), or time (T)360. Additionally, the shutter had two levers—one for cocking the mechanism and another for releasing the shutter360. The release lever was only functional when the shutter was set to instantaneous exposure360.

The serial numbers for the Leica I Model B Dial-Set Compur ranged from 5701 to 6280 (or 6300365) in 1926, and from 13100 to 13163 (or 13139365) in 1927-1928360 (or 1929365). A total of 638 Leica I Model B Dial-Set Compur cameras were known to have been produced360. Although a few others might have been made to special order, these would not have significantly increased the production count360.

Like the early Leica I Model A, variations can also be found among the early Leica I Model B Dial-Set Compur cameras360. For instance, there were differences in the film release buttons (some were indented while others were not), the eyepiece shape (flat or ridged), and the design of the baseplate catches (with or without a bar)360. The first three hundred Leica I Model B Dial-Set Compur cameras featured a non-indented film release and flat eyepieces, while later models have indented releases and curved eyepieces360. Early examples also had a complex type of baseplate catch and film advance and rewind knobs with triple-feathered arrows360.

An important variation was the near-focusing type of Leica I Model B Dial-Set Compur camera, which allowed the lens to focus down to 1.5 feet instead of the standard 3 feet360. To date, only two such cameras had been observed, and they were both found within serial numbers of 5800-5865360.


Leica I Model B Rim-set Compur

The second model, known as the rim-set Compur (or, in German, the ring Compur), was introduced to the market in 1928360. This model differed from its predecessor primarily by the type of shutter used360.

The shutter was equipped with one ring that offers settings B, I, and exposure times ranging from 1 second to 1/300th of a second360. The Leica I Model B Rim-set Compur was produced in small batches over four consecutive years, with serial numbers ranging from 13154360(or 13140365) to 50711360(or 51715365). Most units were produced in 1928 (144 units), 1929 (209 units), and 1931 (81 units)360. According to Mr. W. Hahne's research, some Leica I Model B Rim-set Compur cameras were still being delivered as late as 1941360. These later examples likely consisted of leftover stock from the factory, which was sold when the popular Leica IIIc camera was restricted to military or official use360.

The early serial numbers (from the Leica I Model A range) suggested that these rim-set Compurs were assigned numbers that had not yet been allocated to the Leica I Model A cameras360. Overall, the total production of Leica I Model B Rim-set Compur cameras, about 969 units, represented a fifty percent increase compared to the manufacture of the dial-set model360.

An early sample unit of Leica I Model B Rim-set Compur was illustrated on page 33 of Leica Tsushin No. 6: Mechanism and Prototype in 2002 and in 2018, it was illustrated in Mr. Lars Netopil's "Museum Leica" book596. 

There were a few variations among the rim-set Compurs360: 

  • the shape of the accessory shoe changed from round to square (without indentation)360. Examples were cameras number 32705 and 32745540. The photograph of the former camera appeared on page 36 of James L. Lager's "Leica: An Illustrated History - Volume 1 - Cameras - Signed Deluxe Limited Edition" book540. 
  • very late cameras were fitted with a 50mm f/3.5 Elmar lens that included a serial number360. An example was camera number 50585 fitted with 50mm f/3.5 Elmar lens number 109934540. The photograph of this camera appeared on page 36 of James L. Lager's "Leica: An Illustrated History - Volume 1 - Cameras - Signed Deluxe Limited Edition" book540. 

Additionally, while the Leica I Model A cameras lost their indented, mushroom-shaped film releases at approximately serial number 17000, the rim-set Compurs retained this feature throughout their production run360.