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61-466: The Tessar design uses four spherical lens elements in three groups, one positive crown glass element at the front, one negative flint glass element at the center and a negative concave flint glass element cemented with a positive convex crown glass element at the rear. Despite common belief, the Tessar was not developed from the 1893 Cooke triplet design, although it appears the Tessar replaces

122-533: A 2x backlit exposure switch and a 10 sec timer switch. When the timer is engaged, a flashing LED indicates the timer counter is counting down, for the last two sec, the flash interval shortened. Until 1995, the Minox 35 cameras were considered the smallest cameras for the standard 35 mm film format. The design was inspired by the Rollei 35 , which had been the smallest 35 mm camera for eight years. The Rollei 35

183-563: A camera that could always be carried came to him. Nixi Nylander also coined the name "Minox" and drew up the Minox mouse logo. Jürgens funded the original project but was not able to get support in Estonia for production. Jürgens contacted an English representative of the VEF (Valsts Elektrotehniskā Fabrika) electrotechnical manufacturing business in Riga (by then independent Latvia ) who then arranged

244-434: A diaphragm was deemed unnecessary. The maximum focus zone was about one meter to infinity. In front of the lens was a metal foil curtain shutter, which was itself protected by a window. These were advanced features at the time for any camera, regardless of size. The dimensions of the Minox subminiature camera are: 80 mm × 27 mm x 16 mm; weight: 130 g. The Minox cameras project an image of 8×11 mm onto

305-415: A drawbridge style lens cover which when lowered brought forward a 35 mm focal length f/2.8 four-element, three-group Tessar-type Minotar/Minoxar lens with between the lens leaf shutter and diaphragm, a center positioned viewfinder, two stroke film winder lever and a film rewind knob. The Minox 35 camera back must be removed for loading or unloading film. The camera offered aperture priority exposure with

366-469: A mechanical shutter, while later model Minox ( C, LX, EC, TLX ) cameras have an electromagnetic shutter. When closed, the viewfinder and lens windows are protected. Complan lens and Minox lens are unit focusing lens, focusing from 8 inches (20 cm) to infinity through precision gear linked to a focusing dial on top of the camera. All Minox cameras, except the EC and MX, have a parallax correction viewfinder: when

427-483: A meeting where Zapp demonstrated the Minox prototype ( Ur Minox), with a set of enlargements made from Ur-Minox negatives. Production began in Riga at VEF, running from 1937 until 1943. In the same time, VEF had received patent protection on Zapp's inventions in at least 18 countries worldwide. Shortly after its introduction, the Minox was widely advertised in The European and American markets. It did not surmount

488-493: A new company, Minox GmbH, in Giessen / Heuchelheim near Wetzlar , West Germany . The new camera very much resembled the original, but was made with a plastic chassis covered by an aluminum shell. This greatly reduced its weight and, to an extent, cost. The camera continued to appeal to a luxury "gadget" market which broadened during the 1950s and early 1960s. It also continued to see use as an espionage camera by both sides during

549-544: A positive element and improved zonal correction. Later, Rudolph adopted the same device to modify the Anastigmat design, resulting in the Unar of 1899. In addition, this allowed the photographers to have greater freedom when choosing the lenses. In one implementation, the Unar has four air-spaced elements in four groups, which replaced the two cemented interfaces of the earlier Anastigmat design. In 1902, Rudolph realized

610-401: A round exit pupil. A concave lens of flint glass is commonly combined with a convex lens of crown glass to produce an achromatic doublet . The dispersions of the glasses partially compensate for each other, producing reduced chromatic aberration compared to a singlet lens with the same focal length . Minox Minox (pronounced / ˈ m iː n ɒ k s / MEE -noks )

671-458: A very good optical performance at a reasonable price, and are often quite compact. They are also frequently used in photographic enlargers , as they provide more contrast than many competing lens designs due to the limited number of air-to-glass surfaces. All lenses can be focused by moving the lens assembly towards or away from the film ("unit focusing"), and the Tessar is no exception. Unit-focusing Tessars were used on higher-end cameras such as

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732-509: Is a manufacturer of cameras, known especially for its subminiature camera. The first product to carry the Minox name was a subminiature camera, conceived in 1922, and finally produced in 1936, by Baltic German Walter Zapp . The Latvian factory VEF ( Valsts elektrotehniskā fabrika ) manufactured the camera from 1937 to 1943. After World War II , the camera was redesigned and production resumed in Germany in 1948. Zapp originally envisioned

793-498: Is a type of optical glass used in lenses and other optical components. It has relatively low refractive index (≈1.52) and low dispersion (with Abbe numbers between 50 and 85). Crown glass is produced from alkali-lime silicates containing approximately 10% potassium oxide and is one of the earliest low dispersion glasses . The term originated from crown-glass windows , a method of window production that began in France during

854-653: Is only slightly bigger, but much heavier than the Minox 35 cameras. However, the Minolta TC-1 , introduced in 1996, is smaller. All the above models use a single 5.6 v PX27 battery which can be replaced with two CR 1/3N 3 V Lithium Batteries by using an adapter. All the above, except ML, and MDC use 2 x CR 1/3N 3V Lithium batteries or a single 6V SPX27 silver oxide battery. ML, and MDC use a single 6V PX28 battery. Accessories for Minox 35 include: UV filter, ND filter, lens hood, eveready leather case, and dedicated electronic flash. The few 35 mm cameras offered were of

915-542: Is so important to optical glass technology that many glass names, notably Schott glasses, incorporate it. A K in a Schott name indicates a crown glass ( Krone in German). The B in BK7 indicates that it is a borosilicate glass composition. BAK-4 barium crown glass (glass code 569560) has a higher index of refraction than BK7, and is used for prisms in high-end binoculars. In that application, it gives better image quality and

976-702: The Biotessar consisting of two elements cemented in the front, a single negative element in the center, and three cemented in the rear. After World War II and the partitioning of Germany , the Zeiss factory at Eisfeld ended up in East Germany; Zeiss Jena developed a popular camera line named the 'Werra', after the Werra river which runs through the town. Many models were equipped with Tessar lenses, which were marked as "Zeiss-Tessar", resulting in legal action from

1037-461: The Cold War . During this time, the Minox company continued to develop the camera, working with Gossen to develop a companion miniature exposure meter, as well as improved models such as the Minox B, which incorporated an even smaller Gossen-designed meter into the camera itself. The Minox B became the most popular and widely produced model of the line. Further developments included autoexposure, and

1098-509: The Leica rangefinder camera was a modified Cooke triplet with five elements in three groups, the third group being three cemented elements, with the aperture stop in the first air space. This lens, called the Elmax , gave good coverage of the 24×36 mm format and was used until improved optical glass allowed the third group to be simplified to a cemented pair when it was renamed Elmar . It

1159-513: The "point and shoot" style: MINOX 110S, a 110 film format camera was also once sold. The Minox 110S has a Carl Zeiss Tessar 25 mm/2.8 unit focusing lens, and magicube flash. It is the only camera with a rangefinder made by Minox. An external electronic flashgun was also available. Users report that the 110S provides particularly good results on modern 110 film. Minox briefly expanded its range of 8×11 models by offering Minox- badged cameras styled as miniatures of famous classic film cameras of

1220-450: The BL, there is only a Neutral Density filter. For Riga Minox to Minox B, the film advances each time the camera is closed, regardless of whether a picture is taken or not. Opening the camera causes the pressure plate to press the film into a concave or flat (depending on the model) surface to stiffen thin emulsions for better clarity. When the camera is closed, the pressure plate moves back from

1281-526: The Contaflex Super B, Rolleiflex TLR, and larger-format plate cameras such as the Maximar. Some lenses, including Tessars , can be focused by moving lens elements relative to each other; this usually worsens optical performance to some extent, but is cheaper to implement. As the front element of the Tessar has three times the power of the whole lens, it must be moved one-third of the distance that

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1342-418: The EC, which had a very different internal design and a fixed-focus lens. The production rate for these cameras was considerably slower than in former years, however, as high production costs and increasing competition from Japan sharply reduced sales and revenues. Beginning in 1981, MINOX experienced increasing difficulties. A quarter of the original 750 employees had to be made redundant. A settlement request

1403-773: The Middle Ages. A molten blob of glass was attached to a pole and spun rapidly, flattening it out into a large disk from which windows were cut. The center, called the "crown" or "bullseye", was too thick for windows, but was often used to make lenses or deck prisms . The borosilicate glass Schott BK7 ( glass code 517642) is an extremely common crown glass, used in precision lenses. Borosilicates contain about 10% boric oxide , have good optical and mechanical characteristics, and are resistant to chemical and environmental damage. Other additives used in crown glasses include zinc oxide , phosphorus pentoxide , barium oxide , fluorite and lanthanum oxide . The crown/flint distinction

1464-448: The Minox film cartridge holds 15, 30, or 36 exposures. The VEF Riga has a three-element flat film plane lens. Performance could be improved, so the short-lived Minox II (1948–1951) had a new 5 element lens (called complan) whose final element would rest against the film itself when the pressure plate pushed the film onto the lens. Customers complained of film scratches with this new design, so most of these lenses were replaced by MINOX with

1525-487: The Minox to be a camera for everyone requiring only little photographic knowledge. Yet in part due to its high manufacturing costs, the Minox became more well known as a must-have luxury item. From the start the Minox also gained wide notoriety as a spy camera . Minox branched out into 35 mm film format and 110 film format cameras in 1974 and 1976, respectively. Minox continues to operate today, producing or branding optical and photographic equipment. From 1936 to 1975,

1586-514: The Soviets again. Cameras were produced under both Russian and German occupation nevertheless, and the camera became both a luxury gift item for Nazi leaders as well as a tool for their spies. In the meantime, Zapp and his associates protected their interest in the product by searching for alternative production facilities in Germany. After World War II, production of the Minox II began in 1948 at

1647-618: The United States, and to Krauss in France. Only licensed manufacturers were allowed to use the brand name Tessar . Many other manufacturers tried to copy the design of the Tessar lenses but due to the breadth of the patent, they could not. The simplest way was to use a cemented triplet for the rear group instead of a doublet. In 1913, many designs of this type appeared, including the Ross Xpress by J. Stuart and J.W. Hasselkus, Gundlach Radar , and Berthiot Olor by Florian. After

1708-565: The Zeiss company in Western Germany. For a while the Werra Tessar lenses were marked simply as "T", but eventually they were allowed to market the lenses as "Carl Zeiss – Jena Tessar". Zeiss had strong control over the Tessar design, because Rudolph's patent was very general. In the corresponding U.S. Patent, he claimed: "A spherically, chromatically and astigmatically corrected objective, consisting of four lenses separated by

1769-645: The attention of intelligence agencies in America, Britain and Germany, and most of the Eastern Bloc (East Germany, Romania) due to its small size and macro focusing ability. There is at least one document in the public record of 25 Minox cameras purchased by the US Office of Strategic Services intelligence organisation in 1942. The close-focusing lens and small size of the camera made it perfect for covert uses such as surveillance or document copying. The Minox

1830-527: The company developed an extensive line of accessories. These included flash guns, viewfinder attachments, tripod mounts, and copying stands, all increasing the camera utility in a variety of applications. One accessory even allowed the camera to use a pair of binoculars as a telephoto lens (see illustration). Limited editions of the camera were also produced in a variety of luxury finishes, such as gold plating. Standard cameras were also available in an optional black anodized finish. The Riga Minox camera, along with

1891-479: The diaphragm into two groups each of two lenses, of which groups one includes a pair of facing surfaces and the other a cemented surface, the power of the pair of facing surfaces being negative and that of the cemented surface positive."   — Paul Rudolph , US Pat. 721,240 The Tessar design patent was held by Zeiss for two decades, and licensed to Ross in the United Kingdom, Bausch & Lomb in

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1952-608: The digital still cameras Sony Cyber-shot DSC-P100, DSC-P200, and DSC-W330 as well as the E-mount lenses such as Sony Alpha Carl Zeiss Vario-Tessar T* E 4/16-70mm ZA OSS ( Sony SEL-1670Z ) and Sony Alpha Carl Zeiss Vario-Tessar T* FE 4/16-35mm ZA OSS. Sony also uses Vario-Tessar lens branding for their consumer camcorders such as the HDR-CX405 extending the wide angle view with 1.9mm to 57mm zoom range. Tessar lenses are frequently found in mid-range cameras, as they can provide

2013-404: The exposure meter and electromagnetic shutter. TLX, CLX, ECX use four 1.5v 386 silver oxide button cell in an adapter; this adapter combo can also be used to replace the discontinued 5.6v PX27 battery for Minox C, LX and EC. 8×11mm TLX Special Order models were available new until September 2014. Minox Models The total number of all Minox 8x11 cameras made was about 944,500 units. Matching

2074-468: The film plane, thus allowing the film strip to move freely to advance to the next frame. From Minox BL onward, the camera is equipped with a "freewheeling" mechanism, such that the film advances one frame only when a picture is taken, otherwise, closing the camera does not advance a frame. Minox BL uses a PX625 button cell to power the CdS exposure meter; Minox C, LX, EC, used a 5.6v PX27 mercury battery to power

2135-524: The film report released following the accident investigation. The original Riga-made Minox had a brass chassis covered in a stainless steel shell, which telescopes to reveal or cover the lens and viewfinder windows, as well as to advance the film. It was equipped with a parallax correcting viewfinder, which was coupled to a Cooke triplet type Minostigmat 15 mm f/3.5 lens. The lens was capable of focusing as close as 20 cm, and, due to its small image size, provided such depth of field at full aperture that

2196-419: The focusing dial moves, the viewfinder moves in tandem to correct for parallax. From the Riga to Minox B, the film counter counts up to 50, while from Minox BL, C, to TLX, the film counter counts down from 36/30/15. For mechanical Minox 8x11 cameras, a separate shutter speed dial sets the shutter speed from 1/2 to 1/1000 second, plus B and T (the BL model has no documented T). For electromagnetic shutter cameras,

2257-401: The history of the Minox brand is essentially that of the Minox subminiature camera. From 1975 the Minox name also became associated with other products, most notably the Minox 35 mm compact cameras produced from 1975 until 2004. Minox was acquired by Leica in 1996, but a management buyout on 25 August 2001 left Minox an independent company again. The original Minox subminiature camera

2318-531: The image. The Minox enlarger also holds the negative in this same curve. Later models, beginning with late model Minox B, to the current model TLX, using the 15 mm f/3.5 four-element, three-group flat-field Minox lens, holds the negative flat. The advance was attributed by Rolf Kasemeier (Small MINOX Big Pictures 1971 edition) to new rare-earth element, high-index, low-dispersion, optical glasses becoming available (probably from Schott Glass, of Jena). Note that lens performance between old and new complan/minox lenses

2379-409: The later curved-field compensating lens. Consequently, original 'film lens' Minox II are exceptional. Early Minox cameras from Minox A/III to Minox B were equipped with a four-element, three-group Complan (lens) designed by ex-Leica lens designer Arthur Seibert . The Complan lens has a curved film plane, hence in these cameras the negative must be held in an arc to improve the edge-to-edge sharpness of

2440-514: The luxury finish postwar cameras, are now collector's items. All-mechanical models A and B remain in use by hobbyists. In 1969 the model C became the first camera of its kind to incorporate electronic exposure control. With the introduction of the LX came significant redesign of the camera's basic controls. It was followed by the last production model, the TLX. There was also a fully electronic entry-level model,

2501-412: The minox lens replaced the complan, so the enlargers had to change lenses: MINOX II enlargers were curved negative track and complan lenses, MINOX III enlargers were straight negative track and minox lenses. Ironically, owners of Rigas and model II cameras would get better results from a MINOX III enlarger than a MINOX II enlarger. The early Minox cameras from Riga to Minox B, BL and AX, were equipped with

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2562-500: The name Tessar in common with the original Tessar , not the four-element, three-group design. They are for example a 5-elements-in-1-group, aperture-less all- aspherical lens , as in the Nokia 808 Pureview and Nokia Lumia 800 camera. Vario-Tessar lenses also only have the name Tessar in common with the original Tessar . The Vario-Tessar name has been used by Zeiss for various zoom lenses fitted to Sony cameras, including that of

2623-521: The negative format that the lens is designed to cover, are all vital to the performance of the lens, and in the Leica lens these were all different from the Tessar . When the Leica was being developed, Oskar Barnack tried a 50 mm Tessar , but because it had been designed to cover only the 18×24 mm field of a cine frame, he found it inadequate for coverage of the Leica 24×36 mm format. The lens designed by Max Berek  [ de ] for

2684-459: The negative. The film is in strips 9.2 mm wide, or less than one-quarter the size of 35 mm film, and unlike 35 mm film, it has no sprocket holes. This film strip is rolled up in the supply side chamber of a small twin chamber cartridge, with the film leader taped to a take-up spool in the take up chamber. The film strips can be up to 50 frames in length for Riga Minox and Minox II, III, IIIs and B cameras. From Minox BL and C cameras onward

2745-404: The option of manual settings. The Minox 35ML and Minox M.D.C offer program mode (P mode) exposure in addition to aperture priority. The 35 mm/2.8 Minotar/Minoxar lens was very sharp, with low distortion, while the camera's metering-system's capability to produce excellent results especially under low-light conditions was outstanding – using exposure times of up to two minutes. Some models have

2806-407: The past, manufactured by Sharan Megahouse of Japan, including: All these retro cameras are equipped with 15mm F5.6 triplet lens, and 1/250 sec shutter. Using Minox film in Minox cassette, image size 8x11mm. Later, a range of digital cameras was offered. The digital camera offerings also included similar miniature retro cameras to the 8x11-based models: At photokina in 2008, Minox announced

2867-613: The patent expired, Tessar -derived lenses were widely made by many manufacturers under different trade names. For example, the Minoxar 35/2.8 lens on the Minox M.D.C and GT-E is the fastest and widest Tessar -type lens achieved so far by using lanthanum glass elements. The picture quality was outstanding. Other Tessar -type lenses include: It is sometimes believed the Leitz Elmar 50 mm f /3.5 , designed by Max Berek in 1920,

2928-497: The popularity of 35 mm cameras (which were then referred to as "Miniature Cameras"), but did achieve a niche market. It also attracted the attention of intelligence agencies in America, Britain and Germany, due to its small size and macro focusing ability. Ironically during World War II production of the Minox was put in jeopardy several times as Latvia fell victim to invasion by the Soviet Union , then Germany, and then by

2989-416: The shutter dial starts with 1/15 sec, and ends with 1/1000 (Minox C), or starts with 1/30 and ends with 1/2000 (Minox LX/TLX/CLX); the electromagnetic Minox camera also has an 'A' setting for automatic exposure, controlled by the built-in CdS (Minox C) or Spd (Minox LX/TLX) exposure meter. Above the viewfinder is a filter bar used to slide a yellow, green or an orange filter in front of the lens; starting with

3050-533: The single rear element of the Cooke triplet with a cemented achromatic doublet. Instead, the Tessar underwent a parallel evolution from Paul Rudolph's 1890 Anastigmat lens, which had four elements in two cemented groups. Hugh L. Aldis patented the Stigmatic lens line for Dallmeyer in 1895; in one implementation, the front group from the Anastigmat design was modified by adding a narrow air gap, which acted as

3111-472: The size of the slide film for the 8×11 MINOX cameras, MINOX also produced slide projectors ending with the auto-focus HP24 model. In 1974, Minox introduced a very compact (100 mm × 61 mm × 31 mm), glass fibre reinforced Makrolon bodied 35 mm film camera designed by Professor Fischer of Vienna University: the Minox EL, the first one in Minox 35 mm series. These compact cameras featured

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3172-454: The two cemented interfaces had many virtues, so he reinserted them in the back of his Anastigmat , maintaining the "air gap" of the previous part of the Unar , thus creating the Tessar design (from the Greek word τέσσερα ( téssera , four) to indicate a design of four elements) of 1902. The frontal element of the Tessar , like that of the Anastigmat , had little power since its only function

3233-451: The whole lens would need to move to focus at the same point. The large airspace between the first and second elements allows focusing by moving the front element only; as the displacement is small compared with the airspace, the adverse effect on image performance is not severe. The front-element-focusing Tessar , cheaper than a unit-focusing lens, was widely used in many midrange Zeiss Ikon cameras. Crown glass (optics) Crown glass

3294-433: Was derived from the Tessar , as they share the same general layout. The Elmar lenses were used in the first Leica cameras. Although the Tessar and Elmar lenses appear similar in layout, there is a lot more to the design and performance of a lens than simply the layout of the glass elements. The position of the stop, the optical characteristics of the glasses used for each element, the curvature of each lens surface, and

3355-926: Was filed with the District Court in Giessen on November 21, 1988. Under the direction of the receivership administration, the workforce was reduced to just under 300, and the business was extensively reorganized. The MINOX TLX Camera was available until September 2014. Minox is now part of the Blazer Group GmBH, with its facilities in Isny im Allgäu in the south of Germany, with a service facility remaining in Wetzlar. Production of 8x11 film ended in 2015. The company now produces high-quality sports optics and night-vision devices, its only camera models being trail cameras. The Minox subminiature camera attracted

3416-523: Was invented by Walter Zapp in 1936. Zapp, a Baltic German , was born in 1905 in Riga , then part of the Russian Empire . The family moved to Reval (now called Tallinn , Estonia ) where he first took a job as an engraver before finding a position with a photographer. He became friends with Nikolai 'Nixi' Nylander and Richard Jürgens, and it was through discussions with these friends that the idea of

3477-659: Was not until Zeiss Ikon was developing the Contax camera to compete with the Leica that the Tessar was redesigned to cover a 24×36 mm negative. The front element of the Tessar can be replaced to make a long-focus or wide-angle lens. In 1957 Carl Zeiss offered the long-focus Pro Tessar 115 mm f /4 and 85 mm f /4, and the wide-angle Pro Tessar 35 mm f /3,2 for use on the central-shutter SLR Zeiss Ikon Contaflex Super B cameras. Other Tessar lenses, for example those equipped on certain Nokia mobile phones, have only

3538-655: Was provided with most Minox subminiature cameras, which enabled easy copying of letter-sized documents. The espionage use of the Minox has been portrayed in Hollywood movies and TV shows, and some 1980s Minox advertising has played up the "spy camera" story. A Minox B, operated by remote trigger and protected in a special housing, was used to inspect the interior of the United States Army's SL-1 experimental nuclear reactor after it experienced an internal steam explosion in 1961. This camera and housing were shown in

3599-479: Was rated by MINOX themselves as identical. At this time to differentiate between negatives taken with the older complan lens and negatives taken with the later minox lens, MINOX introduced an edge code in the negative. Since the MINOX C (the first camera released with the new minox lens) every 8x11mm camera had a distinct edge code to identify the camera. The reason was that commercial processors used MINOX enlargers. As

3660-608: Was to correct the few aberrations produced by the powerful posterior element. The set of interfaces cemented in the posterior element had 3 functions: to reduce the spherical aberration; reduce the overcorrected spherical-oblique aberration; and reduce the gap found between astigmatic foci. The first Tessar appeared with a maximum aperture of f /6.3 , but by 1917, the maximum aperture had been increased to f /4.5 . In 1930, Ernst Wandersleb and Willy Merté from Zeiss developed Tessar lenses with apertures of f /3.5 and f /2.8 . In 1925, E. Wandersleb and W. Merté of Zeiss created

3721-483: Was used by both Axis and Allied intelligence agents during World War II . Later versions were used well into the 1980s. The Soviet spy John A. Walker Jr. , whose actions against the US Navy cryptography programs represent some of the most compromising intelligence actions against the United States during the Cold War era, used a Minox C to photograph documents and ciphers. An 18-inch (460 mm) measuring chain

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