--The first edition of the silver (Chrom) collapsible (Collapsible, also known as collapsible five) produced from 1951 to 1957, has two types: screw thread and M mount. Although the performance is good, it is still not as good as the later lenses (not as distinctive as the eight lenses). Due to the design of the fuselage, the head cannot be reduced when used on M5 and CL fuselages. There are 7 lenses in 6 groups. The coating on the front jade is quite soft and is easily scratched or fogged. The minimum focusing distance is 1 meter. Since it can be clearly distinguished from the appearance, the serial numbers of the several versions of Summicron-M 50mm are not absolutely important. I briefly played around with it and took some test photos. My feeling is that anti-flare is completely ineffective, and the same is true when shooting with the aperture reduced. Sometimes there will be a kind of halo like the Buddha appearing, which will completely fade away, not like Summilux-M 35mm pre-ASPH kind of "Glow". This lens has a lot of scratches on the front jade, so it cannot produce acceptable results in terms of resolution. A lens with a prettier lens might be better. Only the contrast performance in black and white films, neither hard nor soft, is the only comfort that makes people feel comfortable. In the early days, it was also one of Henri Cartier-Bresson’s favorite lenses.

-- Second edition 1956-1968, silver (Chrom) Rigid, there are also a small number of specially customized black lacquer versions and precious M39 screw mounts (1160 pieces). From an aesthetic point of view, this lens looks very beautiful, has a focus lever, and feels very good in the hand, so it is sought after by users and players. A Japanese photography magazine (Note) once tested this lens and considered it to have the highest sharpness (compromising lower contrast) among all Summicron 50mms. Note: The 50/2 Summicron mentioned in this paragraph is most likely Leica Communications. It was once thought to have the same optical design as the first version of Summicron, but it has been confirmed that there are indeed some differences between the two lenses. Although the structures of the two lenses are similar, the second and third versions both used four Leica lenses. The developed LaK9 rare earth glass increases the distance between the first and second lenses from 0.28mm to 1.52mm, which solves the problems of aberration and dispersion and improves the resolution, but also makes the image contrast of one or two stops of aperture fully open. Slightly lower (Note 1). There are 7 lenses in 6 groups. The coating of the front lens LaK9 is very soft and can be easily scratched or scratched. The minimum focusing distance is 1 meter. The year of production also includes the 50mm DR, so some documents classify the 50mm Rigid and the 50mm DR as the same version. According to Erwin Putt's information (Simplified Chinese translation), the lens design of the two is considered to be exactly the same. There is also information showing that the second, fifth, and sixth lenses of the 50mm DR have been adjusted for image field flatness, but the information on whether there has been a real revision and the time point are not very clear. (Note 2) Note 1: DR Contrast And The 'rare Earth' Summicron Note 2: The name of a great generation! M 50MM RIGID In this article, there are photos of the front and rear lens groups of the Rigid unscrewed. It seems to be slightly different from the DR (the aperture blade and a section of the lens barrel have also been disassembled), but it is still impossible to confirm the structural difference. It is possible Just focus adjustment for close-up range.

Reference pictures: The engravings of Rigid 1, Rigid 2, and DRRigid have been slightly revised, but there is no clear distinction. The early engravings on the lens mouth were Ernst Leitz GmbH Wetzlar, f=5cm 1:2 Nr.XXXXXX, and the focus ring of the lens body. Only feet or meter (m) are marked, and the word Germany is marked; later lenses are marked LEITZ WETZLAR, there is no Nr. before the serial number, and 1:2/50, and the focus ring of the lens body is marked both feet and meter (m). , and have the words Germany or LENS MADE IN GERMANY. Next to the word m on the lens body that is also marked, the focal length number 19 was written in the early days (19 means that the focal length of the lens is 51.9mm in factory testing, 16 means that the focal length of the lens is 51.6mm in factory testing, and so on if you encounter the same mark) (Note) , and later canceled and did not write. (But it will still be engraved on the internal lens barrel as a factory test certificate)

--The third edition 1956-1968, silver (Chrom) DR (Dual Range) edition with two focus ranges , there are also a small number of special prototype black paint versions. Although most "experts" claim that its optical design is the same as that of the Rigid, according to tests conducted by the famous defunct American photography magazines "American photography magazine" and Modern Photography magazine (note), this 50mm DR is the best lens that has ever been used. The lens has the highest definition among the test lenses, exceeding 100 lp/mm, and its image resolution capability far exceeds that of film. The lens group is the same as the Rigid, with 7 elements in 6 groups. Among all M lenses, it has the strongest near focus capability. At the same time, many experienced DR players claim that the performance of the two lenses is different, and believe that it is due to their different optical designs. Due to the addition of a platform for close-up goggles (SDPOO), the DR is not as attractive in appearance as the Rigid. Despite this, this lens combines high resolution, low contrast, and extremely beautiful bokeh (bokeh), and it is still favored by users. Note: The source of the text is Leica M 50/2 Dual Range Summicron 50mm DR. There has been a minor revision. The early DR version was recently focused to 19 inches (48.26 cm). The lens engraving is Ernst Leitz GmbH Wetzlar, f=5cm 1:2 Nr. .XXXXXX, and the focus ring is slightly narrow, with only feet or meter (m) scales on it (not both at the same time), and the focus ring embossed texture is slightly shallow (knurling ON the ridges). The magnification is also marked from 1:15 to 1:0.75. The early glasses had a framed trademark with "E. Leitz / Wetzlar" written inside. The later DR version recently focused to 20 inches (50.8 centimeters), was stamped LEITZ WETZLAR, had no Nr. before the serial number, and was 1:2/50. The focus ring was slightly wider, and both feet and meter (m) were engraved on it. The magnification is not marked anymore. Its glasses are engraved with "Leitz Wetzlar" text, there is no frame line, and the embossing of the focus ring is larger and deeper (knurling BETWEEN the ridges). The very expensive classic chrome front cover is easy to fall off and get dented or scratched (mine was), so some seniors suggested putting it away and replacing it with a plastic cover, or using an inverted lens hood. Good idea.

(Note) Note: The hood models available for 50mm DR include practical and classic options. References are provided: 12538 (plastic, reversible), 12585 / 12585H (metal, reversible, 12585H has more markings than 12585 1:2/35), ITDOO (cannot be flipped), 12571/IROOA (can be flipped). The 12549 (chrome) / 12550 (black) screw-type (39mm) lens hood for the Elmar-M 50mm is also available, but it cannot be used with protective lenses or filters. It is also said that the coating on the later DR lens is "warmer" and "harder", with better contrast and optical performance (Note 1), but there is no record of changing the optical material, and it is not certain whether all later DR lenses have it. Such a difference. You may need to pay extra attention when purchasing. Because the fixed steel balls on the early glasses platform are larger, the early close-up glasses can be used with later DR lenses, but the later close-up glasses cannot be used with early DR lenses. It is recommended to find someone with When selling a combination with glasses, because DR can be divided into early and late stages, it is also a problem to buy and match them individually. The glasses come with a small leather case, which is also hard to find, but I personally think it is optional. In addition, the coating on the front lens is very soft and is easily scratched or fogged. It is also very likely that the internal coating will deteriorate due to grinding. If it needs to be cleaned, you may have to weigh whether it is worth it. After the DR lens group is unscrewed from the lens barrel, it can also be used with the Leica Visoflex system for close-up shooting with a special adapter (note 2). Generally, when purchasing, you will also check whether the serial numbers of the front and rear lens barrels are consistent. (Please refer to the video) Note 1: The fourth paragraph of the speaker’s speech Note 2: Can the sumicron 50 f2 rigid lens be decomposed? There are simple instructions in the text.

DR can only be attached to the body without glasses. The glasses are an accessory that can be attached and removed at any time (the timing of putting the glasses on and off the lens will be detailed later), and can be easily placed on the platform in front of the RF viewfinder on the body. Leica has stated that this lens cannot be used on the M8 and M9. This may be because the size of the cabin of the M8 and M9 is different from that of the film camera. The rear edge of the lens barrel (the part that drives the linked range-finding mechanism) in the DR close-up focal length range is too large. If it protrudes, it will hit the internal mechanism (note) at normal focal lengths (4m ~ ∞) and cannot be used (or installed). Only close-up focal lengths can be used. Along with M cameras with slightly taller bodies such as M6 TTL and M7, I am not sure whether the close-up glasses can fully cover the RF viewfinder? Epson R-D1, Leica CL, and Minolta CLE can also be equipped with DR, but the close-up glasses will not match the width of the RF viewfinder (the same may be true for M5). Zeiss Ikon ZM and Bessa series can also be installed, but the same glasses will have matching problems and transfer problems. Less than infinity (can only go to the middle of 10m ~ ∞) (Rollei 35RF is OEMed by Cosina and it should be the same). In addition, someone has tried it and found that Konica Hexar RF can fully use 50mm DR. It should be the only non-Leica RF body that can fully use DR. Note: There is a compatibility table in the Compatibility section, and it is also said that it cannot be used at 1m ~ ∞. In short, there will be some problems at general focal lengths.

There are several ways to use DR on M8 and M9. The first one is to directly smooth the protruding part on the rear edge of the lens barrel. However, this will also cause the DR to lose its close-up function. It is better to directly find other 50mm lenses. to use; the second method is more complicated, which is to unscrew the Rigid / DR lenses of the same period, assemble the DR front lens to the rear lens barrel of the Rigid, and then attach it to M8 and M9, so that you can use the general DR lens It works with the focal length (1m ~ ∞); then when using the close-up focal length of M8 or M9, just use the original lens barrel of DR, and then remove the plastic (tab) that is auxiliary fixed on the glasses (note). The experiments of these players have slightly suggested that the structures of Rigid and DR are very similar, and the optical quality of DR is indeed different from Rigid and has its own unique features. Note: Leica M8 amp; 50mm F 2 Summicron DR, Leitz Summicron 50/2 DR used in M8/M9 method, 1963 Summicron 50/2 DR Won't Mount on M8. These three links all say that you can play this way. In addition, there are definitely risks in doing this. If the screw thread breaks or the "clock" causes the lens to shift focus, it will be useless. If you really want to play like this, you need to think clearly. In addition, you may need to pay attention to the internal hand-engraved marks after the front and rear lens groups are unscrewed. That is the actual focal length tested at the factory. It is best to choose the same lens for playing, such as 51.9, so as not to have more problems the more you play with it. (That is to say, there is also the same 51.9, but the focus scale cannot match after combination). The last option is to find an old adapter like UOORF SOMKY to use it with the DR lens set at normal focal lengths and close-up focal lengths. However, it does not seem to be able to fully cover the original close-up focal length of DR, and it is not too easy to use. convenient. Experienced users on the Internet also suggest that when the 50mm DR is to be mounted on the body, it is best to turn it to the infinity position, otherwise the lens may be difficult to mount on the body. The reason is that the DR rear end drives the focusing lens barrel in the close-up range. There is a huge gap between the focusing lens barrel in the normal range. It almost forms a right angle. If the upper and lower body have not been turned to infinity before, it should be disconnected. There is a chance that it will not be able to bypass the RF focusing mechanism and get stuck. When I put the lens up and down, I encountered a situation where the focus scale is closer to the distance range (between 1m and 1.2m), and it gets a little stuck when I take it off. Check that it should be the right-angle stop in the close-up range. Depending on where you live, you can move the camera up and down normally by turning it to 1.5m, but if it is easier to remember the operating procedures, it is easier to turn it directly to infinity.

The user manual recommends that when using the close-up function, after the lens is installed on the body, lift the focus ring upwards and move the latch around the small baffle that separates the intervals to the close-up focal length (stop). At the farthest distance of the close-up range (approximately 88 centimeters on the sight glass), the focus ring will be in a fixed state (please do not turn it with force), and then put on the glasses. After putting on the glasses, you can use the close-up lens correctly. The camera function is enabled. The reason why you need to put on the glasses to turn the focus ring for close-up photography is that the steel ball on the platform for installing the glasses is used to ensure that the glasses have a mounting mechanism to prevent RF damage caused by arbitrary rotation. Some people will press and hold the steel ball to focus close-up, but this is not recommended. After the glasses are installed, the latch will not be able to rotate back to the normal focal length. Please take care of the lens in your hand and do not rotate it hard. Although it is a brass alloy lens barrel, it feels extra solid compared to modern lenses. When you want to remove the lens, you also need to first turn the latch to the farthest distance of the close-up focal length (approximately 88 cm on the sight glass), take off the close-up glasses, and move the latch around the small baffle separating the intervals to the normal range. (More than 1.5m or turn to infinity), then remove the lens. Such tedious instructions are to help readers protect the lens and body in their hands. Although it is tedious, it is actually extremely fun to play.

Another suggestion is to try not to change the close-up focal length on the body, because the focus barrel of the DR that drives the close-up focus has a large gap (refer to Figure 2). Pushing the linked focuser like this for a long time may also damage the function of the RF. . Of course, this has not been confirmed by actual cases, but these words are retained for reference. I have tried it on my M6 non-TTL and DR, and there is no problem in directly converting it. But if you are afraid of damaging the camera body, just take off the lens first, turn the latch to the close-up range, and then put it on the camera. (It’s no problem to go up this way). Remember not to put on your glasses first, because the plastic baffle on the glasses will get stuck in the body. (I mentioned earlier, did you pay attention!!) Some photography enthusiasts in Hong Kong once pointed out that it is difficult to use the close-up function of a post-production DR lens on the M6 ??0.85x (#2296539) body, although there is no problem in mounting the lens on the body. , but something inside the fuselage apparently prevents the lens from working close up. However, it is not certain whether all M6 0.85x bodies will suffer from this problem. So if buying a DR for use with the M6, it's always a good idea to give it a try first. (This early text cannot verify whether the fixed plastic has been removed, nor can it be confirmed whether the M6 ??0.85x is a higher TTL body, or is there something wrong with the matching of the glasses and lens (lens barrel)? Or is it the lens barrel? The problem caused by the large gap in the rear section? Please keep this for reference)

--Fourth edition 1969-1979, black (no copper exposed), no "50" printed on the lens barrel. Focus lever or lock, also known as high five. The lens group was redesigned into 5 groups of 6 elements (the fourth and fifth lenses are each in a group), and it uses four pieces of glass LaFN2 developed by Leitz (Note 1). This design has five flat mirror surfaces, which simplifies the manufacturing and clamping procedures of the lens. Since the double Gaussian structure has considerable residual aspherical aberration, although it has been effectively corrected, the contrast in the center at full aperture is better than Rigid / DR, but there will still be some slight quality degradation outside the center. However, after shrinking 2, After three stops of aperture, the imaging will be significantly improved. The initial production was in Germany, and later the production line was moved to Midland, Ontario, Canada (Note 2). The performance of this lens is also very balanced, its anti-flare ability has become better, and its contrast is slightly higher than the former. Some people joked that "it must be strong every time it rises." The resolution has dropped slightly. Most users think that its performance cannot be compared with the previous and later Summicron-M 50mm. It has no obvious features and has good and bad reviews, but the second-hand price is relatively stable. At that time, after the DR, the Summicron-M 50mm lens could focus the closest, with a minimum focusing distance of 0.7 meters. The same was true for subsequent versions, and it was also the limit of the RF of the M camera. Note 1: The text comes from my Leica rangefinder head and OPTICAL GLASSES Note 2: Some information about Leica made in Germany and Canada (original text)

--Fifth Edition 1979-1994 Black (no copper exposed) ), with "50" printed on the lens barrel and a focus tab, it has two shapes: crescent tab and tiger paw, also commonly known as crescent version or tiger paw version. Until this generation, all Summicron-M 50mm still had external lens hoods (the ones mentioned above). In order to reduce the contact surface between the mirror and the air, the lens group was changed to 4 groups of 6 elements (the fourth and fifth lenses are combined into one group), which improved the image quality. The aperture blades were changed from ten in previous versions to eight, and the weight was only 195 grams, the lightest of all Summicron-M 50mm.

The Summicron-M 50mm with focus lever was initially produced in black and made in Canada. Later, the Wetzlar factory in Canada closed down, and the production line moved back to Germany in 1986 (SOLM's new factory, and the M6 ??entered mass production around that time) (Note 1), some lenses are also produced in special editions and silver (Silver) versions, including 7 pieces (Summicron-M 35mm pre-ASPH) and Summicron-M 50mm. The production volume is not large, so things are rare and expensive. There is also a Leica 70th anniversary commemorative edition released with the M4-P. The lens has the words 1913-1983 on the body and is limited to 800 pieces. It is also sold together with the 200 special edition and the Colombo M6 commemorative machine. By the way, M6 is also the M phone with the most commemorative models, such as: Hello Kitty 20th anniversary commemorative machine... I won’t say more. There is no information that corresponds to the production location in the form of a focus rod (Note 2), and there is no information indicating that the quality of this lens is different between Germany and Canada. I believe that the focus rod only reflects the change in material cost. Optical performance is not significantly different. Note 1: The lens engraving can slightly distinguish the place of origin. Manufactured by Wetzlar in Canada: LEITZ LENS MADE IN CANADA, LEITZ; or manufactured by SOLM in Germany: LEICA (after 1986). The second responds to the history of the factory mentioned. Note 2: There are two types of focus levers produced by the Canadian factory, Picture 1: Canadian Crescent Version, Picture 2: Canadian Tiger Claw Version. Judging from the serial number, the tiger claws precede the crescent moon, so the ones shipped in Canada and even Germany in the later period should be shaped like a crescent moon. I have also been using the fifth version of the Summicorn-M 50mm for some time. The design with the focus lever is very convenient to operate. After getting used to the RF focusing method, my eyes can use the position of the lever and the viewfinder without looking at the depth of field ruler. Line, you can focus and take pictures more quickly, sometimes even faster than autofocus, but of course it depends on your proficiency (note). The optical quality of this version is already a highly respected design. Even the next version has not made any changes. Only the lens barrel has been modified, regardless of color reproduction, anti-flare ability, and full aperture analysis. The resolution and resolution from center to edge are all excellent, and they are all model students with excellent academic performance. Based on my experience at the time, I didn’t feel that the contrast of this version of the lens would be too great. Compared with other newer lenses such as those using ASPH lenses, the contrast was still acceptable. Sometimes slightly improving the contrast can actually increase the three-dimensionality of the picture. This is a very commonly used technique in traditional or digital darkrooms. If you can skillfully operate this lens, its optical performance can be said to be almost impeccable. The performance in color and black and white is quite remarkable, and it has the taste of seven lenses, except of course the bokeh. (Personal opinion) Note: The essence of the Leica lens is the Leica Finger Tab. You can know a little about it by referring to the description in the article.

--Sixth Edition 1994 So far, the last version is generally called the current version. It is available in silver and black (copper will not be exposed). The lens barrel is printed with "50" and is changed to a built-in light shield. hood, and also canceled the focus lever, which can be regarded as slimming down (calculated together with the weight and volume of the hood). The optical design is the same as that of the previous version. There are 6 lens groups in 4 groups. The black version weighs 240 grams, the silver version weighs 335 grams, and a small number of screw thread versions produced in 1999 weigh 325 grams, which is quite rare. In December 2001, Leica produced 500 pieces of the titanium-colored Summicron-M 50mm lens for sale with the M6 ??titanium camera, weighing 335 grams.

And a commemorative version of 1,000 pieces was released in 2003 to commemorate the 50th anniversary of the birth of Summicron-M 50mm. The lens uses the current version material and optical structure, and the appearance is the shape of the second version of Rigid. The above is a rough historical evolution of Summicron-M 50mm. The sixth edition has not been revised for almost 20 years, and its level of completion can be seen as average.