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60-649: The Zorki was a product of the Krasnogorsk Mechanical Factory (KMZ) , which also produced the Zenit single lens reflex camera (SLR). The first Zorki cameras are inexpensive Leica II copies just like the FED , but later models are considerably different from the Leica. When using most Zorki cameras, the shutter speed should only be set after the shutter has been cocked. Setting the shutter speed before

120-642: A collapsible lens which looked like the Leitz Elmar but is actually a copy of the Zeiss Tessar . Introduced in 1948, the "Zorki" was the first 35mm camera made by KMZ. The Zorki S of 1955 added flash synchronization . The Zorki 2 (1954) is similar to the Zorki but features an updated rewind mechanism, a self timer and strap lugs. There is a later flash version called the Zorki 2S . Introduced in 1951,

180-428: A complete exposure could be finished faster, with the subjects having to hold still for a shorter length of time. Emulsions that were less sensitive were deemed "slower" as the time to complete an exposure was much longer and often usable only for still life photography . Exposure times for photographic emulsions shortened from hours to fractions of a second by the late 19th century. In both film and digital photography,

240-545: A hundredfold increase in sensitivity. Thus emulsions that differed by 1° Sch. on the Scheiner scale were 100 19 = 1.2742... {\displaystyle {\sqrt[{19}]{100}}=1.2742...} -fold more (or, less) sensitive to each other. An increment of 3° Sch. came close to a doubling of sensitivity ( 100 19 ) 3 = 2.06914... {\displaystyle ({\sqrt[{19}]{100}})^{3}=2.06914...} . The system

300-434: A major revision in 1960 with ASA PH2.5-1960, when the method to determine film speed was refined and previously applied safety factors against under-exposure were abandoned, effectively doubling the nominal speed of many black-and-white negative films. For example, an Ilford HP3 that had been rated at 200 ASA before 1960 was labeled 400 ASA afterwards without any change to the emulsion. Similar changes were applied to

360-466: A reputation as one of the best Russian cameras, although the self timer and slow shutter speeds are unreliable. The Zorki Mir of 1959 is a lower-cost Zorki 4 with fewer shutter speeds. The Zorki-35M full-frame 35mm coupled-rangefinder camera is from a project undertaken by KMZ designer N. Marienkov during the late 1960s (the "M" is his "signature" camera; he also designed the Zorki 3M and the Zenit 3M). It

420-750: A standardized method of sensitometry put forward by the Deutscher Normenausschuß für Phototechnik as proposed by the committee for sensitometry of the Deutsche Gesellschaft für photographische Forschung since 1930 and presented by Robert Luther  [ de ] (1868–1945) and Emanuel Goldberg (1881–1970) at the influential VIII. International Congress of Photography (German: Internationaler Kongreß für wissenschaftliche und angewandte Photographie ) held in Dresden from 3 to 8 August 1931. The DIN system

480-542: Is a Russian factory in Krasnogorsk near Moscow which specializes in optical technology. Part of Shvabe Holding ( Rostec state corporation). During the Soviet period it was called Krasnogorsk Mechanical Works ( Красногорский механический завод , Krasnogorskiy Mechanicheskiy Zavod ). The abbreviation KMZ ( КМЗ ) is still in common use. KMZ is known largely for its photographic and movie cameras of

540-478: Is a modern-style 35mm rangefinder camera with a selenium light meter and shutter priority automatic exposure introduced in 1964. The Zorki 11 is a cheaper model without the rangefinder, and the Zorki 12 is a variant using Agfa 's Rapid film  [ de ; ru ] cartridges. All three variants have fixed (non-interchangeable) lenses. The Zorki 10 is a fixed-lens Zorki coupled rangefinder camera with an integrated light meter. Selenium meter cells surround

600-409: Is a small lever protruding from the right-hand side of the lens. Shutter speeds from 1/30s to 1/500s are available in automatic mode. It also provides a B ( bulb ) setting, though there is no way to attach a cable release. Apertures from 2.8 to 22 with constant shutter speed of 1/30 s can be set in manual mode, intended for use with an electronic flash. Flash sync is possible at all shutter speeds through

660-404: Is based on the body of the Zenit E and some of the advanced design features of the Zenit D, but is a rangefinder rather than SLR camera. It features bright-line frames in the viewfinder for 50mm and 85mm lenses, with the entire field of the viewfinder corresponding to that of a 35mm lens. Other advances include automatic parallax compensation, speeds from 1 to 1/1000 sec. and a modern body design. It

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720-496: Is defined as the speed point at which the slope of the characteristic curve first reaches a fixed fraction (e.g. 0.3) of the average gradient over a range (e.g. 1.5) of the characteristic curve. The first known practical sensitometer , which allowed measurements of the speed of photographic materials, was invented by the Polish engineer Leon Warnerke  – pseudonym of Władysław Małachowski (1837–1900) – in 1880, among

780-673: Is described in ISO ;12232:2019 (first published in August 1998, revised in April 2006, corrected in October 2006 and again revised in February 2019). The ISO system defines both an arithmetic and a logarithmic scale . The arithmetic ISO scale corresponds to the arithmetic ASA system, where a doubling of film sensitivity is represented by a doubling of the numerical film speed value. In

840-512: The DIN system with DIN 4512:1961-10 and the BS system with BS 1380:1963 in the following years. In addition to the established arithmetic speed scale, ASA PH2.5-1960 also introduced logarithmic ASA grades (100 ASA = 5° ASA), where a difference of 1° ASA represented a full exposure stop and therefore the doubling of a film speed. For some while, ASA grades were also printed on film boxes, and they saw life in

900-589: The General Electric Photo Data Book . General Electric switched to use the ASA scale in 1946. Meters manufactured since February 1946 are equipped with the ASA scale (labeled "Exposure Index") already. For some of the older meters with scales in "Film Speed" or "Film Value" (e.g. models DW-48, DW-49 as well as early DW-58 and GW-68 variants), replaceable hoods with ASA scales were available from

960-609: The ISO film speed system between 1982 and 1987, however, the arithmetic ASA speed scale continued to live on as the linear speed value of the ISO system. GOST (Cyrillic: ГОСТ ) was an arithmetic film speed scale defined in GOST ;2817-45 and GOST 2817–50. It was used in the former Soviet Union since October 1951, replacing Hurter & Driffield (H&D, Cyrillic: ХиД) numbers, which had been used since 1928. GOST 2817-50

1020-569: The ISO system introduced in 1974. A closely related system, also known as ISO, is used to describe the relationship between exposure and output image lightness in digital cameras. Prior to ISO, the most common systems were ASA in the United States and DIN in Europe. The term speed comes from the early days of photography. Photographic emulsions that were more sensitive to light needed less time to generate an acceptable image and thus

1080-730: The Zorki , Zenit and Krasnogorsk series, several million of which were produced. It also has a large military optics and mechanical engineering division. After the German invasion of the Soviet Union in World War II , the Red Army had acute need for precision optical instruments. The existing factories were either inaccessible, such as LOMO in besieged Leningrad , or overloaded with demand, such as FED which had just been evacuated from Kharkiv to Berdsk . The KMZ factory

1140-464: The Zorki 3 is somewhat similar to the Leica III . It offers a number of improvements over the original Zorki, including a large combined viewfinder with the rangefinder builtin, a removable back, and a larger and faster Jupiter-8 ( Zeiss Sonnar copy) lens. It also adds a new mechanism for slow shutter speeds with a separate selector dial on the front of the camera. This mechanism was unreliable, so

1200-622: The fractional gradient criterion of the American 1943 standard, and also included arithmetic speed numbers in addition to logarithmic numbers. The logarithmic speed number proposed in the later BS 1380:1957 standard was almost identical to the DIN ;4512:1957 standard, except that the BS number was +9 degrees greater than the corresponding DIN number; in 1971, the BS and DIN standards changed this to +10 degrees. Following an increasing effort to produce international standards,

1260-494: The ASA scale by adding the same amount, that is, a film rating of 100 Weston (up to 1955) corresponded with 125 ASA (as per ASA PH2.5-1954 and before). This conversion was not necessary on Weston meters manufactured and Weston film ratings published since 1956 due to their inherent use of the ASA system; however the changes of the ASA PH2.5-1960 revision may be taken into account when comparing with newer ASA or ISO values. Prior to

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1320-605: The British, American, and German standards became identical in ISO 6:1974, which corresponded to BS 1380:Part1:1973. Before the advent of the ASA system, the system of Weston film speed ratings was introduced by Edward Faraday Weston (1878–1971) and his father Dr. Edward Weston (1850–1936), a British-born electrical engineer, industrialist and founder of the US-based Weston Electrical Instrument Corporation , with

1380-820: The German DIN 4512 system has been effectively superseded in the 1980s by ISO 6:1974, ISO 2240:1982, and ISO 5800:1979 where the same sensitivity is written in linear and logarithmic form as "ISO 100/21°" (now again with degree symbol). These ISO standards were subsequently adopted by DIN as well. Finally, the latest DIN 4512 revisions were replaced by corresponding ISO standards, DIN 4512-1:1993-05 by DIN ISO 6:1996-02 in September 2000, DIN 4512-4:1985-08 by DIN ISO 2240:1998-06 and DIN 4512-5:1990-11 by DIN ISO 5800:1998-06 both in July 2002. When BS  935:1941

1440-724: The ISO standards since 1974. The current International Standard for measuring the speed of color negative film is ISO 5800:2001 (first published in 1979, revised in November 1987) from the International Organization for Standardization (ISO). Related standards ISO 6:1993 (first published in 1974) and ISO 2240:2003 (first published in July 1982, revised in September 1994 and corrected in October 2003) define scales for speeds of black-and-white negative film and color reversal film, respectively. The determination of ISO speeds with digital still-cameras

1500-1291: The PC terminal. There is an accessory shoe provided, but it does not sync with flash. The Zorki 11 is a Zorki 10 without the coupled rangefinder mechanism, but with distance symbols visible in the viewfinder. Technical specifications: Film type: 135 Frame size: 24x36 mm Viewfinder magnification: 0.65x Rangefinder base: 38 mm Lens: Industar 63, 45 mm f/2.8 (four element Tessar type) Angle of view: 51.3 degree Min. focusing distance: 1.5 m Shutter: leaf ; electronically controlled in auto mode, 1/30 s or B in manual mode. Exposure metering: external with selenium meter Shutter speed range: 1/30 s – 1/500 s, B Aperture range: 2.8 – 22 Automatic exposure range: 8 – 18 EV Manual exposure range: 8 – 14 EV Film speed range: 20 – 320 ASA (14 – 26 DIN, 16 – 250 GOST) Flash sync: 1/30 s Film advance: manual Self timer: mechanical, 8-15 s delay Filter thread: M52.5 x 0.75 Tripod thread: 1/4" or 3/8" (depending on manufacture period) Dimensions: 129 x 77 x 76 mm Weight: 750 g Krasnogorsky Zavod Krasnogorsky zavod ( Russian : Красногорский завод им. С. А. Зверева , lit.   'Krasnogorsk Works named after S. A. Zverev')

1560-625: The Red Army and largely carted off as war reparations . The mid-1950s saw the beginning of a period of heightened R&D activity at KMZ. During this period, KMZ also produced the world's first subminiature SLR camera, the Narciss, an all-metal camera using 16mm unperforated film in special cassette, frame size 14x21mm. Narciss has a focal plane shutter, speed B,1/2,1/5,1/10,1/25,1/50,1/125,1/250 and 1/500 sec. The pace of R&D for consumer products at KMZ substantially slowed down at

1620-592: The Swiss-born Ferdinand Hurter (1844–1898) and British Vero Charles Driffield (1848–1915). In their system, speed numbers were inversely proportional to the exposure required. For example, an emulsion rated at 250 H&D would require ten times the exposure of an emulsion rated at 2500 H&D. The methods to determine the sensitivity were later modified in 1925 (in regard to the light source used) and in 1928 (regarding light source, developer and proportional factor)—this later variant

1680-518: The USSR and further: Before 1949 the KMZ logo was a simple dove prism , nicknamed "tomb" by factory workers. In 1949 the logo was changed to the present form, depicting a prism with a refracted ray of light . Film speed#ASA Film speed is the measure of a photographic film 's sensitivity to light , determined by sensitometry and measured on various numerical scales , the most recent being

1740-660: The Weston model 617, one of the earliest photo-electric exposure meters, in August 1932. The meter and film rating system were invented by William Nelson Goodwin, Jr. , who worked for them and later received a Howard N. Potts Medal for his contributions to engineering. The company tested and frequently published speed ratings for most films of the time. Weston film speed ratings could since be found on most Weston exposure meters and were sometimes referred to by film manufacturers and third parties in their exposure guidelines. Since manufacturers were sometimes creative about film speeds,

1800-472: The Zorki 5 is loaded with film by removing the bottom plate. However, both versions of the Zorki 5 have a flaw where cycling the shutter with no lens on the camera causes the rangefinder arm to get caught up in the shutter mechanism, possibly breaking the camera in the process. The Zorki 6 fixed this problem with the Zorki 5 by moving the rangefinder arm to the other side of the lens mount and introduced an Zenit-style swing back for easier loading. The Zorki 10

1860-567: The achievements for which he was awarded the Progress Medal of the Photographic Society of Great Britain in 1882. It was commercialized since 1881. The Warnerke Standard Sensitometer consisted of a frame holding an opaque screen with an array of typically 25 numbered, gradually pigmented squares brought into contact with the photographic plate during a timed test exposure under a phosphorescent tablet excited before by

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1920-413: The company went as far as to warn users about unauthorized uses of their film ratings in their "Weston film ratings" booklets. The Weston Cadet (model 852 introduced in 1949), Direct Reading (model 853 introduced 1954) and Master III (models 737 and S141.3 introduced in 1956) were the first in their line of exposure meters to switch and utilize the meanwhile established ASA scale instead. Other models used

1980-699: The definition of film speeds in order to accommodate then-recent changes in the American ASA PH2.5-1960 standard, so that film speeds of black-and-white negative film effectively would become doubled, that is, a film previously marked as "18° DIN" would now be labeled as "21 DIN" without emulsion changes. Originally only meant for black-and-white negative film, the system was later extended and regrouped into nine parts, including DIN 4512-1:1971-04 for black-and-white negative film, DIN 4512-4:1977-06 for color reversal film and DIN 4512-5:1977-10 for color negative film. On an international level

2040-415: The end of the 1960s. During the 1970s consumer production at KMZ shifted towards producing large numbers of individual, relatively simple models of the existing product lines. After the collapse of the Soviet Union , KMZ production was largely in disarray. Now, it is a group member of the multi-national Russian Shvabe Holding. The activities of PJSC NKMZ include PJSC KMZ also carries out measures for

2100-410: The establishment of the ASA scale and similar to Weston film speed ratings another manufacturer of photo-electric exposure meters, General Electric , developed its own rating system of so-called General Electric film values (often abbreviated as G-E or GE ) around 1937. Film speed values for use with their meters were published in regularly updated General Electric Film Values leaflets and in

2160-439: The fading intensity of the light emitted by the phosphorescent tablet after its excitation as well as high built-tolerances. The concept, however, was later built upon in 1900 by Henry Chapman Jones (1855–1932) in the development of his plate tester and modified speed system. Another early practical system for measuring the sensitivity of an emulsion was that of Hurter and Driffield (H&D), originally described in 1890, by

2220-603: The form of the APEX speed value S v (without degree symbol) as well. ASA PH2.5-1960 was revised as ANSI PH2.5-1979, without the logarithmic speeds, and later replaced by NAPM IT2.5–1986 of the National Association of Photographic Manufacturers, which represented the US adoption of the international standard ISO 6. The latest issue of ANSI/NAPM IT2.5 was published in 1993. The standard for color negative film

2280-617: The idea of comparability. Scheiner's system was eventually abandoned in Germany, when the standardized DIN system was introduced in 1934. In various forms, it continued to be in widespread use in other countries for some time. The DIN system, officially DIN standard 4512 by the Deutsches Institut für Normung (then known as the Deutscher Normenausschuß (DNA)), was published in January 1934. It grew out of drafts for

2340-410: The improved Zorki 3M of 1954 (also produced in 1955) combines all of the shutter speeds on a single dial. The Zorki 3S , introduced in 1955, is a Zorki 3M with flash sync. The Zorki 4 , 1956, is a Zorki 3S with self timer added. The Zorki 4K is identical but used an advance lever instead of the old-style wind knob. With over 2 million units produced, the Zorki 4 is the most successful Zorki and has

2400-452: The intercept between the gradient of the straight line part of the curve and the line representing the base + fog (B+F) on the density axis. The fixed density speed point is determined by defining a fixed minimum density as the basis the emulsion speed (e.g. 0.1 above B+F). The minimum useful gradient criterion places the speed point where the gradient first reaches an agreed value (e.g. tan 𝜃 = 0.2). The fractional gradient

2460-478: The late 19th century, listed here by name and date, these criteria are: threshold (1880), inertia (1890), fixed density (1934), minimum useful gradient (1939) and fractional gradient (1939). The threshold criterion is the point on the characteristic curve corresponding to just perceptible density above fog. The inertia speed point of an emulsion is determined on the Hurter and Driffield characteristic curve by

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2520-469: The lens. This was the first fully automatic camera produced in the former Soviet Union, as well as the first to use ASA / DIN markings rather than the Soviet GOST numbers, however these ASA numbers were still mostly useless as they didn't match any known film speeds (some Zorki 10 cameras apparently had GOST numbers instead of ASA though, as it's shown in a Polish camera manual). The shutter release

2580-461: The light of a burning magnesium ribbon. The speed of the emulsion was then expressed in 'degrees' Warnerke (sometimes seen as Warn. or °W.) corresponding with the last number visible on the exposed plate after development and fixation. Each number represented an increase of 1/3 in speed, typical plate speeds were between 10° and 25° Warnerke at the time. His system saw some success but proved to be unreliable due to its spectral sensitivity to light,

2640-449: The logarithmic ISO scale, which corresponds to the DIN scale, adding 3° to the numerical value constitutes a doubling of sensitivity. For example, a film rated ISO 200/24° is twice as sensitive as one rated ISO 100/21°. Commonly, the logarithmic speed is omitted; for example, "ISO 100" denotes "ISO 100/21°", while logarithmic ISO speeds are written as "ISO 21°" as per

2700-580: The manufacturer. The company continued to publish recommended film values after that date, however, they were then aligned to the ASA scale. Based on earlier research work by Loyd Ancile Jones (1884–1954) of Kodak and inspired by the systems of Weston film speed ratings and General Electric film values , the American Standards Association (now named ANSI) defined a new method to determine and specify film speeds of black-and-white negative films in 1943. ASA Z38.2.1–1943

2760-479: The original Weston scale up until ca. 1955. The company continued to publish Weston film ratings after 1955, but while their recommended values often differed slightly from the ASA film speeds found on film boxes, these newer Weston values were based on the ASA system and had to be converted for use with older Weston meters by subtracting 1/3 exposure stop as per Weston's recommendation. Vice versa, "old" Weston film speed ratings could be converted into "new" Westons and

2820-598: The repair of military equipment, warranty and author's supervision of its condition, implements proposals in the field of military-technical cooperation of the Russian Federation with foreign states in accordance with international treaties of the Russian Federation. Since its establishment as Precision Mechanics Plant No.19: Since its transformation into the State Union Plant No.393 of the NKVD of

2880-405: The sensitivity was written as a fraction with 'tenths' (for example "18/10° DIN"), where the resultant value 1.8 represented the relative base 10 logarithm of the speed. 'Tenths' were later abandoned with DIN 4512:1957-11, and the example above would be written as "18° DIN". The degree symbol was finally dropped with DIN 4512:1961-10. This revision also saw significant changes in

2940-506: The shutter is cocked can permanently damage the camera. This especially affects all Zorki cameras with slow shutter speeds under 1/30 of a second, in particular the Zorki-3 and Zorki-4. The first Zorki was the Zorki (called " Zorki 1 " by some for clarity, although it never had a number in the name), an exact copy of the 1932 Leica II rangefinder. It featured a 50mm f/3.5 Industar-22 lens,

3000-417: The speed of a plate by the least exposure to produce a visible darkening upon development. Speed was expressed in degrees Scheiner, originally ranging from 1° to 20° Sch., with each increment of a degree corresponding to a multiplicative factor of increased light sensitivity. This multiplicative factor was determined by the constraint that an increment of 19° Sch. (from 1° to 20° Sch.) corresponded to

3060-443: The use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise ). Generally, the higher the sensitivity, the grainier the image will be. Ultimately sensitivity is limited by the quantum efficiency of the film or sensor. To determine the exposure time needed for a given film, a light meter is typically used. Five criteria for the rating of emulsion speed have been used since

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3120-434: Was inspired by Scheiner 's system, but the sensitivities were represented as the base 10 logarithm of the sensitivity multiplied by 10, similar to decibels . Thus an increase of 20° (and not 19° as in Scheiner's system) represented a hundredfold increase in sensitivity, and a difference of 3° was much closer to the base 10 logarithm of 2 (0.30103...): As in the Scheiner system, speeds were expressed in 'degrees'. Originally

3180-463: Was introduced as ASA PH2.27-1965 and saw a string of revisions in 1971, 1976, 1979, and 1981, before it finally became ANSI IT2.27–1988 prior to its withdrawal. Color reversal film speeds were defined in ANSI PH2.21-1983, which was revised in 1989 before it became ANSI/NAPM IT2.21 in 1994, the US adoption of the ISO 2240 standard. On an international level, the ASA system was superseded by

3240-762: Was later extended to cover larger ranges and some of its practical shortcomings were addressed by the Austrian scientist Josef Maria Eder (1855–1944) and Flemish-born botanist Walter Hecht  [ de ] (1896–1960), (who, in 1919/1920, jointly developed their Eder–Hecht neutral wedge sensitometer measuring emulsion speeds in Eder–Hecht grades). It remained difficult for manufacturers to reliably determine film speeds, often only by comparing with competing products, so that an increasing number of modified semi-Scheiner-based systems started to spread, which no longer followed Scheiner's original procedures and thereby defeated

3300-434: Was probably an attempt to make an updated alternative for the then aging Zorki 4. At least two hand-built prototypes of this camera are known to exist, and the KMZ archives list it as a "project", but it never went into production. The Zorki 5 is an updated model similar to the FED 2 . There are two different versions, the first (1958) having an Industar-22 lens and the second (1959) having an Industar-50. Like early Leicas,

3360-652: Was published during World War II , specifying exposure tables for negative materials, it employed the same fixed-density speed criterion used in the German DIN  4512:1934 system. The British Standard also used logarithmic speed numbers, following the example of Scheiner and DIN. When the American ASA ;Z38.2.1:1943 standard was published, it used a fractional gradient speed criterion and arithmetic speed numbers, for compatibility with Weston and GE . British standard BS 1380:1947 adopted

3420-403: Was revised in 1946 and 1947 before the standard grew into ASA PH2.5-1954. Originally, ASA values were frequently referred to as American standard speed numbers or ASA exposure-index numbers . (See also: Exposure Index (EI).) The ASA scale is a linear scale, that is, a film denoted as having a film speed of 200 ASA is twice as fast as a film with 100 ASA. The ASA standard underwent

3480-546: Was set up in 1942 near Moscow, which by then was no longer in immediate danger from German troops, on the site of a recently evacuated mechanical plant. Initially the company took over production of scopes and binoculars as well as reconnaissance cameras. After the end of the war, KMZ began producing photographic lenses in 1945 to the specifications of the Carl Zeiss corporation, whose factory in Jena had been overrun by

3540-626: Was similar to the ASA standard, having been based on a speed point at a density 0.2 above base plus fog, as opposed to the ASA's 0.1. GOST markings are only found on pre-1987 photographic equipment (film, cameras, lightmeters , etc.) of Soviet Union manufacture. On 1 January 1987, the GOST scale was realigned to the ISO scale with GOST 10691–84, This evolved into multiple parts including GOST 10691.6–88 and GOST 10691.5–88, which both became functional on 1 January 1991. The ASA and DIN film speed standards have been combined into

3600-485: Was sometimes called "H&D 10". The H&D system was officially accepted as a standard in the former Soviet Union from 1928 until September 1951, when it was superseded by GOST  2817–50. The Scheinergrade (Sch.) system was devised by the German astronomer Julius Scheiner (1858–1913) in 1894 originally as a method of comparing the speeds of plates used for astronomical photography. Scheiner's system rated

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