M-Mount Cameras Not Made by Leica, Part 1
They’re all ingenious and some took the Leica M concept to new levels
By Jason Schneider
The official German Patent Specification document for the iconic Leica M mount states that the patent was first applied for on 8 July 1949 and formally issued on 23 October 1952 to Hugo Wehrenfennig of Wetzlar. Wehrenfennig, a brilliant mechanical engineer working at E. Leitz Wetzlar, had previously developed a rotating delay mechanism that enabled long shutter speeds to be set via the single non-rotating shutter speed dial used on the Leica M3, and was also responsible for designing the mechanical components of the first Leica M lenses.
According to “50 YEARS LEICA M” the authoritative volume by Günter Osterloh, the highest priority for the Leica M3 design team was “assigned to the bayonet for interchangeable lenses. It had to be created in such a way as to ensure precise parallel seating and exact latching in order to satisfy all the requirements for automatic and accurate coupling of lenses, viewfinder and rangefinder.” Wehrenfennig “selected a four-part (that is, 4-lobed) bayonet. It is only with this shape that the maximal amount of light coming from the optical system reaches the outermost corners of the image. It was also his idea to reduce the flange-to-film distance by one millimeter, which made it possible to use screw-mount lenses on Leica M cameras by means of dedicated bayonet adapters.” These adapters also keyed in the appropriate bright-line frame in the camera’s viewfinder.
So why didn’t everyone and his brother just start making M-mount cameras to compete with the Leica M models as they had done with screw-mount “Barnack” Leicas starting in the 1930s? The story, like almost everything connected with Leica, is more complicated than it first appears According to a retired patent attorney who represented Eastman Kodak Co. for many years, “These Leica M-mount patents certainly expired in the 1970s. Nowadays, most patents expire 20 years from filing, and most of the time you can't request that a patent term be extended, unless, for example, it’s a pharmaceutical patent and you needed to wait for regulatory approval.”
However, not everyone agrees with that view, including the late, great tech wizard and camera expert Tom Abrahamsson who posted the following tantalizing tidbit on Rangefinder Forum:
“Leica had a patent on the M-mount, and it did run out on 31 December 1998. There were actually two patents, one for the product, and one for the design. As the design patent had run its 50-year course once it lapsed it could not be renewed without a great deal of difficulty, and rumor has it that Leica forgot about it and thought that the patent applied to the M3 (which would have run out in in 2004). That’s why Konica had to hold off on introducing their (M-mount-compatible) KM-mount Hexar RF 35mm rangefinder camera until 1 January 1999, as it would have posed a legal issue if it had been released ‘officially’ at Photokina 1998.”
According to Wikipedia, Konica introduced the Konica Hexar RF to the market on 13 October 1999, making it the first official non-Leica camera with, in effect, an M-mount. However, for political reasons Konica steadfastly referred to it as a “Bayonet Konica KM-mount” and never claimed their system to be compatible with Leica M cameras or lenses even though it was. More on that later. However, the Hexar RF wasn’t the very first unofficial M-mount camera. That honor goes to the Shanghai Red Flag 20 (aka Hong Qi 20), an unabashed copy of the Leica M4 hand assembled in China in very limited quantities in the early to mid ‘70s. At the time China didn’t believe it was bound by international patents, and they just went ahead and made it, allegedly to coincide with the 20th anniversary of the Chinese Communist Party.
The Red Flag saga
The entire story of this remarkable camera would fill a small book, so here are the essentials. The Red Flag 20 is essentially a replica of the Leica M4, but its viewfinder has projected parallax-compensating frame lines for 35mm 50mm, and 90mm lenses like the Leica M2, but lacks the 135mm frame line present in the Leica M4. It is said to have been made on the orders of the government, was hand assembled from precision components fabricated at universities and research centers in various parts of China, and was produced in very limited quantities—one credible estimate is 187 units, most furnished as a kit with 3 lenses, hoods, cases, etc. The first batch of Red Flag 20 kits arrived in 1973 with 35mm f/1.4, 50mm f/1.4, and 90mm f/2 lenses, all close copies of their Leitz Summilux and Summicron counterparts and made using glass imported from East Germany. Understandably the production cost per unit was staggering and these cameras were essentially a nationalistic demonstration project never intended to be sold through normal channels. Most wound up in the hands of high-ranking communist party officials, favored photojournalists, and celebrities.
Shanghai Red Flag 20 outfit with 35mm f/1.4, 50mm f/1.4 and 90mm f/2 lenses.
While the Red Flag 20 is a far cry from a Leica M4 in terms of overall quality it is nicely made and reasonably well finished. Users say it’s reliable, and that its lenses perform very well indeed. In short it was a stunning achievement for an emerging country that was pursuing a policy of absolute self-reliance in the waning years of Mao Zedong’s rule (he died in 1976). It’s also fully compatible with the Leica M system and works flawlessly with Leica M lenses. As you might imagine, Red Flag 20 outfits are vanishingly rare, and fetch stratospheric prices among well-heeled collectors. A complete 3-lens Shanghai Red Flag 20 outfit in excellent used condition sold for the equivalent of $75,000 at the LEITZ PHOTOGRAPHICA AUCTION on 22 November 2014.
Shanghai Red Flag 20 with 50mm f/1.4 lens, original box, hood, and matching self-timer.
Konica Hexar RF
The Konica Hexar RF that debuted in 1999 is a sleek, well-executed interchangeable-lens KM-mount rangefinder camera closely patterned on the M-series Leicas of the era but taking the concept a few steps farther in terms of technology. KM is Konica’s designation for its copy the Leica M mount. The RF’s signature features are a built-in motor drive with single and continuous (2 fps) advance modes and auto rewind, and an electronically controlled, vertical travel, metal focal plane shutter with continuous speeds of 16-1/4000 sec in center weighted aperture priority AE mode, and 1-1/4000 sec in discrete steps in manual exposure mode, plus B. The range/viewfinder has a long 68.5mm base length and 0.6x magnification, giving an effective base length (EBL) of 41.1mm, sufficient to provide accurate focusing with most M-mount and all KM-mount lenses. Like the Leica Ms, the rangefinder provides both coincident image and split-image methods to enhance focusing accuracy, and the viewfinder offers 6 different auto-indexing, parallax compensating projected frame lines that appear in pairs—50mm and 75mm, 28mm and 90mm, and 35mm and 135mm—as found in later Leica models such as the Leica M4-P. The camera also provides a frame line preview lever and has a built-in self-timer.
Konica RF PRO-HALF is ultra rare; only 50 were made! Logo is on side, below neck strap lug.
Konica offered a series of high-performance M-Hexanon lenses for the Hexar RF. The 28mm f/2.8, 35mm f/2, standard 50mm f/2 and 90mm f/2.8 were introduced in 1999 along with the camera. The rare 50mm f/1.2 Hexanon was available only with the Hexar RF Limited, a limited- edition kit of 2001 units, each in a boxed set with flash. These now fetch fancy prices ($3,000-$4,000) among collectors. There was also an extremely rare (50 units made!) half frame Hexar RF called the PRO-HALF that runs upwards of $6,000 even in rough condition if you can find one. Konica discontinued the Hexar RF, apparently without notice, before the end of 2003, an ignominious end to a worthy contender.
Konica Hexar RF Limited with 50mm f/1.2 M-Hexanon lens.
The Konica Hexar RF performed very well overall and was more advanced than its posh competitors from Wetzlar, but it had one nagging problem that dinged its reputation—the KM mount, which was tacitly supposed to be identical to the Leica M-mount, was occasionally out of spec, especially on early production models, leading to noticeable focusing errors with some M-mount lenses. Here’s the story according to one expert who was in a position to know: Before the Hexar RF went into production Konica’s engineers approached Leitz and asked them whether their specs for the M-mount were accurate but didn’t ask them about the precise manufacturing tolerances required. Leitz responded that Konica’s specs were correct, but understandably did not divulge any additional un-asked-for information to a potential competitor. As a result, it was possible for slight out of spec tolerances to cascade in a positive (plus) direction, leading to out of spec mounts and noticeable focusing errors. The defect could be corrected fairly easily at the factory or by qualified camera repairmen, and the error was evidently fixed on later models, but questions lingered in the minds of potential consumers. But Hexar RF fans got the last laugh—a pristine example with 50mm f/2 M-Hexanon now goes for about 2 grand!
Konica Hexar RF in black finish with 50mm f/2 M+Hexanon lens.
Voigtlander Bessa T
Released in March 2001, the innovative Voigtlander Bessa T was the first Cosina-made rangefinder 35 to sport a Leica M-mount, and it’s fully compatible with Leica M-mount and Konica KM-mount lenses. When it was introduced it was the least expensive M-mount camera on the market and it accepts a bottom-mount trigger winder capable of about 2-3 frames per sec. The Bessa T’s signature feature is a long base 1.5x magnification rangefinder with an effective base length (EBL) of 53.7mm, surpassing many Leica M cameras. It was the first non-Leica M capable of accurately focusing such lenses as a 75mm f/1.4 or 135mm f/3.4 over their entire focusing ranges down to 3 feet, and it provides +-/2 diopter eyepiece adjustment. The tradeoff: the T has no viewfinder, relying on shoe-mount accessory finders, which makes for slightly slower operation in the style of a classic Barnack Leica that has separate rangefinder and viewfinder windows. On the plus side those big, bright accessory finders generally provide a larger viewing image than built-in finders and many include manual parallax compensation.
Voigtlander Bessa T, 101 Heliar Anniversary Edition with 50mm f/3.5 Heliar lens, trigger winder.
Other Bessa T features include: a 145-degree ratcheted film wind lever, a Copal-derived, mechanical, vertical travel, metal focal-plane shutter with speeds of 1-1/2000 sec plus B an X synch at 1/125 sec that works without battery power, a center-weighted silicon cell meter that reads light reflected off first shutter curtain and provides LED meter readouts in finder, and a standard PC flash contact. The Bessa T was available in black, silver, gray and navy blue and (for the 101 Heliar Anniversary Set only) in olive. Speaking of viewing, its fully compatible with the M-mount Visoflex II and III reflex housings. The Voigtlander Bessa T was discontinued on 1 May 2004, but near mint examples are readily available on the used market (body only) at around $500 and about $1,500-$2,000 for the 101 Heliar Anniversary version with Heliar lens.
They’re all ingenious and some took the Leica M concept to new levels
By Jason Schneider
The official German Patent Specification document for the iconic Leica M mount states that the patent was first applied for on 8 July 1949 and formally issued on 23 October 1952 to Hugo Wehrenfennig of Wetzlar. Wehrenfennig, a brilliant mechanical engineer working at E. Leitz Wetzlar, had previously developed a rotating delay mechanism that enabled long shutter speeds to be set via the single non-rotating shutter speed dial used on the Leica M3, and was also responsible for designing the mechanical components of the first Leica M lenses.
According to “50 YEARS LEICA M” the authoritative volume by Günter Osterloh, the highest priority for the Leica M3 design team was “assigned to the bayonet for interchangeable lenses. It had to be created in such a way as to ensure precise parallel seating and exact latching in order to satisfy all the requirements for automatic and accurate coupling of lenses, viewfinder and rangefinder.” Wehrenfennig “selected a four-part (that is, 4-lobed) bayonet. It is only with this shape that the maximal amount of light coming from the optical system reaches the outermost corners of the image. It was also his idea to reduce the flange-to-film distance by one millimeter, which made it possible to use screw-mount lenses on Leica M cameras by means of dedicated bayonet adapters.” These adapters also keyed in the appropriate bright-line frame in the camera’s viewfinder.
So why didn’t everyone and his brother just start making M-mount cameras to compete with the Leica M models as they had done with screw-mount “Barnack” Leicas starting in the 1930s? The story, like almost everything connected with Leica, is more complicated than it first appears According to a retired patent attorney who represented Eastman Kodak Co. for many years, “These Leica M-mount patents certainly expired in the 1970s. Nowadays, most patents expire 20 years from filing, and most of the time you can't request that a patent term be extended, unless, for example, it’s a pharmaceutical patent and you needed to wait for regulatory approval.”
However, not everyone agrees with that view, including the late, great tech wizard and camera expert Tom Abrahamsson who posted the following tantalizing tidbit on Rangefinder Forum:
“Leica had a patent on the M-mount, and it did run out on 31 December 1998. There were actually two patents, one for the product, and one for the design. As the design patent had run its 50-year course once it lapsed it could not be renewed without a great deal of difficulty, and rumor has it that Leica forgot about it and thought that the patent applied to the M3 (which would have run out in in 2004). That’s why Konica had to hold off on introducing their (M-mount-compatible) KM-mount Hexar RF 35mm rangefinder camera until 1 January 1999, as it would have posed a legal issue if it had been released ‘officially’ at Photokina 1998.”
According to Wikipedia, Konica introduced the Konica Hexar RF to the market on 13 October 1999, making it the first official non-Leica camera with, in effect, an M-mount. However, for political reasons Konica steadfastly referred to it as a “Bayonet Konica KM-mount” and never claimed their system to be compatible with Leica M cameras or lenses even though it was. More on that later. However, the Hexar RF wasn’t the very first unofficial M-mount camera. That honor goes to the Shanghai Red Flag 20 (aka Hong Qi 20), an unabashed copy of the Leica M4 hand assembled in China in very limited quantities in the early to mid ‘70s. At the time China didn’t believe it was bound by international patents, and they just went ahead and made it, allegedly to coincide with the 20th anniversary of the Chinese Communist Party.
The Red Flag saga
The entire story of this remarkable camera would fill a small book, so here are the essentials. The Red Flag 20 is essentially a replica of the Leica M4, but its viewfinder has projected parallax-compensating frame lines for 35mm 50mm, and 90mm lenses like the Leica M2, but lacks the 135mm frame line present in the Leica M4. It is said to have been made on the orders of the government, was hand assembled from precision components fabricated at universities and research centers in various parts of China, and was produced in very limited quantities—one credible estimate is 187 units, most furnished as a kit with 3 lenses, hoods, cases, etc. The first batch of Red Flag 20 kits arrived in 1973 with 35mm f/1.4, 50mm f/1.4, and 90mm f/2 lenses, all close copies of their Leitz Summilux and Summicron counterparts and made using glass imported from East Germany. Understandably the production cost per unit was staggering and these cameras were essentially a nationalistic demonstration project never intended to be sold through normal channels. Most wound up in the hands of high-ranking communist party officials, favored photojournalists, and celebrities.
Shanghai Red Flag 20 outfit with 35mm f/1.4, 50mm f/1.4 and 90mm f/2 lenses.
While the Red Flag 20 is a far cry from a Leica M4 in terms of overall quality it is nicely made and reasonably well finished. Users say it’s reliable, and that its lenses perform very well indeed. In short it was a stunning achievement for an emerging country that was pursuing a policy of absolute self-reliance in the waning years of Mao Zedong’s rule (he died in 1976). It’s also fully compatible with the Leica M system and works flawlessly with Leica M lenses. As you might imagine, Red Flag 20 outfits are vanishingly rare, and fetch stratospheric prices among well-heeled collectors. A complete 3-lens Shanghai Red Flag 20 outfit in excellent used condition sold for the equivalent of $75,000 at the LEITZ PHOTOGRAPHICA AUCTION on 22 November 2014.
Shanghai Red Flag 20 with 50mm f/1.4 lens, original box, hood, and matching self-timer.
Konica Hexar RF
The Konica Hexar RF that debuted in 1999 is a sleek, well-executed interchangeable-lens KM-mount rangefinder camera closely patterned on the M-series Leicas of the era but taking the concept a few steps farther in terms of technology. KM is Konica’s designation for its copy the Leica M mount. The RF’s signature features are a built-in motor drive with single and continuous (2 fps) advance modes and auto rewind, and an electronically controlled, vertical travel, metal focal plane shutter with continuous speeds of 16-1/4000 sec in center weighted aperture priority AE mode, and 1-1/4000 sec in discrete steps in manual exposure mode, plus B. The range/viewfinder has a long 68.5mm base length and 0.6x magnification, giving an effective base length (EBL) of 41.1mm, sufficient to provide accurate focusing with most M-mount and all KM-mount lenses. Like the Leica Ms, the rangefinder provides both coincident image and split-image methods to enhance focusing accuracy, and the viewfinder offers 6 different auto-indexing, parallax compensating projected frame lines that appear in pairs—50mm and 75mm, 28mm and 90mm, and 35mm and 135mm—as found in later Leica models such as the Leica M4-P. The camera also provides a frame line preview lever and has a built-in self-timer.
Konica RF PRO-HALF is ultra rare; only 50 were made! Logo is on side, below neck strap lug.
Konica offered a series of high-performance M-Hexanon lenses for the Hexar RF. The 28mm f/2.8, 35mm f/2, standard 50mm f/2 and 90mm f/2.8 were introduced in 1999 along with the camera. The rare 50mm f/1.2 Hexanon was available only with the Hexar RF Limited, a limited- edition kit of 2001 units, each in a boxed set with flash. These now fetch fancy prices ($3,000-$4,000) among collectors. There was also an extremely rare (50 units made!) half frame Hexar RF called the PRO-HALF that runs upwards of $6,000 even in rough condition if you can find one. Konica discontinued the Hexar RF, apparently without notice, before the end of 2003, an ignominious end to a worthy contender.
Konica Hexar RF Limited with 50mm f/1.2 M-Hexanon lens.
The Konica Hexar RF performed very well overall and was more advanced than its posh competitors from Wetzlar, but it had one nagging problem that dinged its reputation—the KM mount, which was tacitly supposed to be identical to the Leica M-mount, was occasionally out of spec, especially on early production models, leading to noticeable focusing errors with some M-mount lenses. Here’s the story according to one expert who was in a position to know: Before the Hexar RF went into production Konica’s engineers approached Leitz and asked them whether their specs for the M-mount were accurate but didn’t ask them about the precise manufacturing tolerances required. Leitz responded that Konica’s specs were correct, but understandably did not divulge any additional un-asked-for information to a potential competitor. As a result, it was possible for slight out of spec tolerances to cascade in a positive (plus) direction, leading to out of spec mounts and noticeable focusing errors. The defect could be corrected fairly easily at the factory or by qualified camera repairmen, and the error was evidently fixed on later models, but questions lingered in the minds of potential consumers. But Hexar RF fans got the last laugh—a pristine example with 50mm f/2 M-Hexanon now goes for about 2 grand!
Konica Hexar RF in black finish with 50mm f/2 M+Hexanon lens.
Voigtlander Bessa T
Released in March 2001, the innovative Voigtlander Bessa T was the first Cosina-made rangefinder 35 to sport a Leica M-mount, and it’s fully compatible with Leica M-mount and Konica KM-mount lenses. When it was introduced it was the least expensive M-mount camera on the market and it accepts a bottom-mount trigger winder capable of about 2-3 frames per sec. The Bessa T’s signature feature is a long base 1.5x magnification rangefinder with an effective base length (EBL) of 53.7mm, surpassing many Leica M cameras. It was the first non-Leica M capable of accurately focusing such lenses as a 75mm f/1.4 or 135mm f/3.4 over their entire focusing ranges down to 3 feet, and it provides +-/2 diopter eyepiece adjustment. The tradeoff: the T has no viewfinder, relying on shoe-mount accessory finders, which makes for slightly slower operation in the style of a classic Barnack Leica that has separate rangefinder and viewfinder windows. On the plus side those big, bright accessory finders generally provide a larger viewing image than built-in finders and many include manual parallax compensation.
Voigtlander Bessa T, 101 Heliar Anniversary Edition with 50mm f/3.5 Heliar lens, trigger winder.
Other Bessa T features include: a 145-degree ratcheted film wind lever, a Copal-derived, mechanical, vertical travel, metal focal-plane shutter with speeds of 1-1/2000 sec plus B an X synch at 1/125 sec that works without battery power, a center-weighted silicon cell meter that reads light reflected off first shutter curtain and provides LED meter readouts in finder, and a standard PC flash contact. The Bessa T was available in black, silver, gray and navy blue and (for the 101 Heliar Anniversary Set only) in olive. Speaking of viewing, its fully compatible with the M-mount Visoflex II and III reflex housings. The Voigtlander Bessa T was discontinued on 1 May 2004, but near mint examples are readily available on the used market (body only) at around $500 and about $1,500-$2,000 for the 101 Heliar Anniversary version with Heliar lens.
Really like the Bessa T 
