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98-483: It covers from the first " Asahiflex " models in 1952 and their successor, the pivotal "Asahi Pentax" single-lens reflex camera , last made in 1997, to the present time known as "Pentax" first made in 1981. The period around 1950 marked the return of the Japanese photographic industry to the vigorous level of the early 1940s, and its emergence as a major exporter. The newly reborn industry had sold many of its cameras to

196-471: A Minolta patent, but utilised in the Olympus OM-2 in 1975. The selected aperture value and shutter speed are shown in the viewfinder. It had a large range of accessories which were mostly not interchangeable with other contemporary cameras. It remained in production for more than 20 years. The A series added fully programmed exposure control (adjusting both aperture and shutter speed automatically) to

294-552: 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 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

392-946: A doubling of sensitivity ( 100 19 ) 3 = 2.06914... {\displaystyle ({\sqrt[{19}]{100}})^{3}=2.06914...} . The system 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

490-476: A given film, a light meter is typically used. Five criteria for the rating of emulsion speed have been used since 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

588-567: A major reason for the greater popularity of the rangefinder. With the IIB there emerged the first practical quick-return mirror, a vital innovation and one which was quickly adopted by other manufacturers. With the final model in the series, the IIA, the Asahiflex gained slow speeds from 1/25th of a second to 1/2 of a second. A recognized problem with the Asahiflex series was that, lacking a pentaprism, it

686-434: 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

784-630: A mechanical aperture ring in some lenses and these are fully compatible with both film and digital SLRs. SAFOX VIII are integrated into this camera series. In May 2006, Pentax announced a new line of Digital SLR cameras to replace Digital *ist series. The K100D and K110D replaced *ist DL2 and DS2, while incorporating in-body shake reduction in the K100D model. The Pentax K10D , a new flagship model in Digital K series replaced *ist D, adopted Sony 10-megapixel CCD sensor and weather-sealing construction,

882-541: A new series of lenses designated D FA 645 (featuring Weather Sealing on all such lenses) was also released. Asahiflex Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.237 via cp1104 cp1104, Varnish XID 197128735 Upstream caches: cp1104 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 07:39:54 GMT Film speed Film speed

980-582: A new series of lenses that were designed only to cover the smaller sensor. These are the DA series for their digital SLRs, which still feature the K-mount but have a smaller back-focus element designed specifically for use with the Digital SLR lineup. The DA series lenses do not have a mechanical aperture ring and so are not backward compatible with some earlier film bodies. The later D-FA lens series re-introduces

1078-568: A non-interchangeable waist-level viewfinder, with a direct optical viewfinder for eye-level use. The Asahiflex I had a non-returning mirror and shutter speeds from 1/25 to 1/500. The camera used the M37 screw mount. It went through some minor modifications for flash use, resulting in the IA. With the IIB a key advance was made: the quick-return mirror. The problem of mirror black-out was one of the main problems with prior SLR designs, greatly reducing usability and

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1176-449: A pentaprism viewfinder covering 100% of the frame, 720p video capture, a quieter and faster shutter mechanism, and the ability to apply automatic corrections for lens distortion and lateral chromatic aberration . This flagship model uses a 77 multi-zone metering system and updated focus - SAFOX VIII+. The K-7 was available from July 2009. In September 2009 the K-x , was introduced to replace

1274-399: A second by the late 19th century. In both film and digital photography, 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

1372-410: A spotmeter, through the taking lens, an incredible innovation. The camera excited tremendous attention and in 1964 the first production Spotmatic (hyphen dropped) emerged. The Spotmatic was virtually identical to the prototype; however, the spotmeter was replaced with an all-over average-reading exposure meter in order to give more consistent results. The camera was an instant success and was snapped up by

1470-750: 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

1568-673: 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

1666-457: Is determined on the Hurter and Driffield characteristic curve by 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

1764-460: Is externally almost identical to the 1964 SV. However, by the 1960s the clamour for in-camera exposure metering was rising. It was possible to attach an external CdS ( Cadmium sulfide ) exposure meter to the later AP-derived models, but in 1960 the next breakthrough arrived. At the 1960 photokina camera show, Asahi exhibited the Spot-matic prototype. This camera took exposure measurements, via

1862-630: Is the measure of a photographic film 's sensitivity to light , determined by sensitometry and measured on various numerical scales , the most recent being 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

1960-512: 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

2058-589: 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

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2156-561: 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

2254-552: The Pentax 645D . The camera has been in and out of development since 2003 and went on sale in Japan in May 2010 at RRP of ¥850,000, with supplies to the rest of the world expected to start soon after. It is targeted at professionals doing outdoor photography—camera body features very high level of airtightness. It uses a 40 megapixels , 44 mm × 33 mm CCD sensor . At the same time,

2352-622: 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,

2450-494: 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

2548-408: The Asahiflex. This is, however not very likely, since the cameras are very different in mechanical construction and form, although the specifications show many similarities. According to other sources, it was a pre-war Reflex Corelle, owned by president Mr. Matsumoto, that inspired the Asahiflex. The camera was designed by two engineers who had previously worked at Konishi (Konica). The Asahiflex I had

2646-605: 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

2744-548: The Contax D, were products of the East German branch of Zeiss Ikon, circa 1949. There are other stories, too. The word PEN in Japanese actually means small, so you might think that this is the explanation, but it is not. In fact the name Pentax comes from a contraction of PENTAprism and AsahifleX. This was confirmed by the international sales department of Asahi Optical Co. in 1999. The Asahi Pentax of 1957 featured: Moreover,

2842-606: The ES series, only had manual shutter speeds from 1/60 upwards. The K2 DMD was a special version of the K2 that could use a data back and motor drive (hence "DMD"), together with other enhancements that aimed it at the professional market. The K1000 was the KM without the self-timer, depth of field preview and some other facilities, and was aimed at the lower end of the market in which it was very successful and continued in production until 1997, helped by

2940-820: 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

3038-724: 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

Pentax cameras - Misplaced Pages Continue

3136-822: The K10D, among other improvements, while retaining the smaller body size of the K100D Super . The K-m / K2000 for US was announced on September 22, 2008 at the 2008 photokina trade show along with the DA-L series of lightweight, inexpensive lenses. On May 20, 2009, Pentax announced the K-7 as a replacement for the K20D . It introduced an updated version of the Samsung CMOS sensor, but with an entirely new compact design. Notable new features included full metal body construction,

3234-626: The K2 DMD as the Pentax 35mm flagship. It is rugged, weatherised and sealed against dust, yet compact and light. It has interchangeable viewfinders (more than any of its rivals) and focusing screens ; the S69 screen being particularly bright. The LX uses an advanced metering system that also reads the light falling on the film and the first shutter curtain during exposure, the TTL OTF (off the film) feature,

3332-478: The K2, KX and KM. The K2 DMD and K1000 followed in 1976. What set these cameras apart from earlier Pentax ones was the replacement of the M42 "universal" screw-lens mount with a proprietary bayonet mount system, known as the K mount. Still the basis for Pentax lenses and cameras today, the K mount offered greater convenience and enabled the production of faster lenses such as the 50 mm f /1.2 . To keep M42 users in

3430-464: The KA and K mounts: MZ-S (Flagship model) MZ-3 MZ-5 MZ-5n MZ-10 MZ-7 MZ-6/ZX-L MZ-M (manual focus version and no built in flash) Models which were backward compatible with the KA mount but not the K mount: MZ50 MZ30 MZ60 *ist (2003–2006) A full complement of exposure modes, Av, Tv, Program, Bulb and Manual, plus a few "scene" modes. Auto-exposure backward compatible with

3528-473: The KA mount but not the K mount. K mount lenses can be used in Manual mode, but the metering needs to be made separately and applied manually, with no indication of aperture in the viewfinder. Can also use M42 screw-mount lenses in aperture priority (Av) with stop-down metering with the appropriate M42-PK adaptor fitted. Auto-focus available for all "screw-drive" lenses, but no power contacts for power zoom or

3626-399: The M series. To enable control of the lens aperture by the camera body, it used the new KA-mount, a backward-compatible modification that also allowed the array of standard K-mount lenses to be used in manual and aperture-priority exposure modes. The A series were the first cameras from Pentax to use LCD digital displays for exposure information in the viewfinder. The super A / super PROGRAM and

3724-619: The ME, the MX was designed as a manual-only SLR system targeted to the advanced amateur or professional photographer, and had its own set of accessories that were mostly incompatible with the other M series cameras. Conversely, the other M-series cameras were targeted squarely at casual users. None of the M-series, with the exception of the MX, featured a depth of field preview. The ME featured aperture-priority only automation with no manual override. The MX

3822-859: The P3/P30 also offered Av mode , and the P5/P50 offered exposure compensation of ±3 EV. The SFX (called the SF1 in the US) was the world's first AF SLR with built-in TTL auto flash, which is retractable. Pentax has referred to the built-in flash as "RTF" (Retractable TTL Flash) ever since then. Pentax SAFOX I (Sensor Ability Fortifying Optical Correction System) autofocus module was integrated to these series. The second generation of autofocus cameras from Pentax. They are equipped with new SAFOX II autofocus module and power contact to enable power zoom function in power zoom FA lenses. In

3920-526: The Pentax placed controls in locations that would become standard on 35 mm SLRs from all manufacturers, such as the right-handed rapid wind lever, the bottom right mounted rewind release, and film speed reminder around the film rewind crank. The photographic giants Canon & Nikon , did not introduce their own SLR cameras until 1959 with the Canonflex and the F-series respectively. By contrast,

4018-399: The Pentax series offered these features at a relatively low price, introducing many photographers to 35 mm SLR photography. The Asahi Pentax series went through various iterations until 1964. Each successive model incorporated minor improvements, the most noticeable being the incorporation of the two shutter speed dials (one for high speeds and one for low speeds) into one. The AP of 1957

Pentax cameras - Misplaced Pages Continue

4116-451: The Pentax system, an M42-K Mount adaptor was offered, enabling them to continue to use their existing lenses, albeit with the loss of automation and needing to accept "stop-down" metering, which causes the viewfinder's image to brighten or darken whenever the aperture's f/stop is changed. The K series cameras followed the design ethos of the previous Pentax Spotmatic series cameras, which were large and heavy, although rugged. But by 1975 there

4214-590: The Spotmatic F except for the K mount and the top plate cosmetics. It used a rather dated and slow CdS (cadmium sulfide) photocell for metering. The KX featured a better light meter using SPD (silicon photodiodes), visible aperture and shutter speeds in the viewfinder, and a mirror lock-up mechanism. The K2, the original flagship model, incorporated aperture-priority autoexposure with a fully manually selectable range of shutter speeds from 8s to 1/1000. The only other aperture priority camera Pentax had made up to this point,

4312-603: The United States the series was called PZ , while in the rest of the world it was called Z . This innovative series brought the "small and light" concept back from previous generation manual focus cameras. This series known as MZ models elsewhere were named ZX models in the USA except MZ-S, the MZ-5 being known as the ZX-5 in the USA. The exception to this rule was the MZ-6 which was known as

4410-660: 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,

4508-940: The ZX-L in the USA. Models shown on the same row are model replacements/upgrades in the range, so the MZ-10 was replaced by the MZ-7 which was subsequently replaced by the MZ-6. All members of this series are compact autofocus SLRs except the MZ-M. The flagship model in this series is the MZ-S which body materials are metal, faster film drive and higher flash sync speed. Only MZ-S and MZ-6 are compatible with newly introduced P-TTL flash system. Both models can control remote flash wirelessly by popup flash commander mode in normal or high-speed flash sync. SAFOX IV/V autofocus module are integrated into this series. Models which were also backward compatible with both

4606-530: The aperture set. With these innovative developments, the Metallica pioneered features that would not surface on Pentax production cameras until the Electro-Spotmatic (ES) (automatic aperture-priority exposure) in 1971, ES II in 1973 and K2 (vertical metal shutter, bayonet lens mount, automatic aperture-priority exposure) in 1975. (Cecchi 1991:80-86) Three new models were introduced at once in 1975:

4704-757: The camera without an anti-aliasing filter would be sold as the K-5 IIs. Both cameras were released in October 2012. In June 2013 Pentax announced the successors to the K-30, the K-50 and K-500 . Both are mid-level DSLRs, the K-500 being a stripped-down version of the K-50, having no weather seals and less-advanced electronics. Pentax K-500 uses 4 AA batteries (rechargeable Lithium battery is optional), while Pentax K-50 uses rechargeable Lithium battery. In October 2013 Pentax launched

4802-413: 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

4900-411: The competition was the clarity and high magnification provided by their pentaprism viewfinders, a very useful feature considering the support for legacy manual focus lenses. In 2005 Pentax released the Pentax *ist DL , a model with fewer features than the D and DS with a lower price. All Pentax's digital SLRs are compatible with K-mount lenses, and M42 (42 mm screw mount) lenses (with adaptor). Due to

4998-699: 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

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5096-410: The design of 35 mm SLRs worldwide for years to come. The Pentax and its later development and likewise classic 1964 Pentax Spotmatic spurred the development of Asahi into a photographic multinational company , eventually renaming itself "Pentax" after its seminal product. The Pentax series remains pivotal in the development of modern SLR photography. There is some confusion about the etymology of

5194-501: The early days of photography. Photographic emulsions that were more sensitive to light needed less time to generate an acceptable image and thus 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

5292-600: The entry level K-m / K2000 (US) . A review by Imaging Resource emphasised its "excellent high ISO performance" and "excellent print quality". In September 2010 Pentax announced the K-r , a 6 frames per second 12.4 megapixel camera and the K-5 , a 7 frames per second 16.3 megapixel camera. These cameras use a new, faster autofocus system, SAFOX IX. In February 2012 information about the Pentax K-01 Mirrorless camera

5390-410: 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

5488-453: The fact that for many years it was the camera usually recommended for students starting photographic or art courses. The M series cameras were noted for their compact size, and are among the smallest 35 mm SLRs ever made, though they are quite heavy when compared to the plastic SLRs of the 1990s. Except for the MX, all were based on the same basic camera body, and featured aperture-priority exposure automation. While superficially resembling

5586-448: The first flagship model, the Pentax *ist D which uses a Sony 6 megapixel CCD . Since 2003, the *ist D is the only digital SLR that can control HS wireless P-TTL from its pop-up flash and has many advanced features for professional applications. In 2004 Pentax released the second member in the digital *ist line, the Pentax *ist DS which is the first real consumer model (retailing under US$ 1,000). What set Pentax D and DS DSLRs apart from

5684-433: 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

5782-443: 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

5880-430: The later lenses with built-in focus motors. Aperture and shutter information visible in the viewfinder. Focus confirmation in the viewfinder for all lenses of f/5.6 or wider. 17 Custom Functions to help configure the camera to individual preferences. Uses an infra-red sensor for film transport, making the camera unsuitable for infra-red photography. The Pentax MZ-D , also known by its internal code name of MR-52 ,

5978-400: 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

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6076-496: 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

6174-432: The name. Most sources claim it was licensed from VEB Pentacon the East German successor to Zeiss Ikon, and is derived from the combination " PENT aprism" and "cont AX ", in the same way that "Pentacon" was taken from " PENTA prism" and " CON tax". It's known that the "Pentax" name was originally registered as a trademark by VEB Pentacon, duly noting that both the M42 lens mount and the first recognizably modern 35mm SLR camera,

6272-478: The next 40 years. In 1960, the same year that Asahi Optical introduced the Spot-matic prototype at photokina, they also showed another SLR prototype which they called the Metallica. The Metallica gave a glimpse into the future direction of Pentax cameras; it featured a prototype bayonet lens mount, a vertical-traveling, metallic Copal-type focal plane shutter (from which the camera drew its name), and an already obsolescent coupled selenium light meter . The light meter

6370-433: The occupation forces (with hugely more disposable income than the Japanese) and they were well received. The Korean War saw a huge influx of journalists and photographers to the Far East , where they were impressed by lenses from companies such as Nikon and Canon for their Leica rangefinder cameras, and also by bodies by these and other companies to supplement and replace the Leica and Contax cameras they were using. This

6468-479: 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

6566-452: The photographic plate during a timed test exposure under a phosphorescent tablet excited before by 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

6664-440: The power zoom function as the K10D. On January 23, 2008, Pentax announced the K20D and K200D , which replaced the K10D and K100D series respectively. The K20D featured a Samsung 14.6 megapixel CMOS APS-C sized sensor, a special 21  frame/s burst mode , live preview on the LCD display, and an increased sensitivity range extending to ISO 3200. The K200D adopted the 10 megapixel sensor and weather sealing of

6762-450: The power zoom function in some FA lens that Pentax introduced in the 1990s. In addition, the K10D could write JPEGs and two versions of RAW files (PEF, and the Adobe specification DNG ). The K100D Super was a slight upgrade to the K100D announced in June 2007. The upgrade included some features from the K10D, such as an improved shake reduction (SR) system, a dust removal system, and power contacts for SDM lenses, but which could not enable

6860-407: The program A / program PLUS both used a translucent white window on the front of the pentaprism to provide backlight to the LCD display without having to use the battery for illumination. The P series featured fully programmed exposure control (in addition to manual mode), DX-code film speed setting (defaulting to 100 if the code couldn't be read), exposure lock and depth of field preview. All but

6958-441: The retail price had dropped by 50% and after a year the model was discontinued. Pentax announced a new mid-level DSLR, the K-30 , in May 2012. It has the same APS-C sensor and processor as the K-01, and is fully weather-sealed. In September 2012, Pentax announced the successor to the K-5, the K-5 II . It has the same APS-C sensor as the K-5, but has an improved autofocus sensor and a redesigned rear LCD with no air gap. A version of

7056-530: The sensitivity of an emulsion was that of Hurter and Driffield (H&D), originally described in 1890, by 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

7154-405: 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

7252-413: 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 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

7350-456: The smaller size of the CCD, lenses have an effective field of view of 1.5 × times the same lens in 35 mm format. So, where a 50 mm lens was considered a "normal" lens on 35 mm film, that same lens on a 1.5× "crop factor" camera has the field of view of a 75 mm lens on film. This only uses the center of the lens' projected image. To address this "crop factor," Pentax created

7448-423: The speed point where the gradient first reaches an agreed value (e.g. tan 𝜃 = 0.2). The fractional gradient 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,

7546-475: The stop-down metering of the early models). However, by the mid-1970s the limitations of the M42 mount were being felt. By this time most other manufacturers had opted for a bayonet lens mount. It was a great step for Asahi Optical to take but the M42 screw mount, by now widely known as ' Pentax screw mount ', had reached the end of its useful life. Pentax were now to adopt the K-mount that would see them through

7644-631: The successor to the K-5ii and K-5iis, the Pentax K-3 . The K-3 is the first DSLR to use its shake reduction system to function as an anti-aliasing filter. It has a 24.71 megapixel sensor and other improvements over the K-5 but maintains the rugged stainless steel frame and magnesium alloy body construction, complete with 92 body seals thereby rendering the camera cold-proof and water resistant. In March 2010 Pentax announced its first medium format digital camera,

7742-625: The thousands, although Asahi had been beaten into production by the Topcon RE Super which went on sale in April 1963; the Topcon failed to attract the same degree of commercial success. The Spotmatic was replaced by the Spotmatic II with many upgrades 1971 - 1976. In 1966 Asahi Optical had produced one million SLR cameras since the first Asahiflex of 1962. It took them only another three years, until 1969, to reach two million. This period

7840-440: The time. His system saw some success but proved to be unreliable due to its spectral sensitivity to light, 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

7938-612: Was a prototype digital single-lens reflex camera . It was announced at photokina in September 2000 and was demonstrated to the press at the Photo Marketing Association (PMA) show in January 2001. In October 2003, Pentax canceled the camera, stating "The cost of manufacturing the prototype SLR 6-megapixel digital camera meant it was not a viable product for our target market." In 2003 Pentax introduced their first Digital SLR under Digital *ist series and released

8036-437: Was a time of complete pre-eminence for Asahi Optical. During the Spotmatic era Asahi were manufacturing more SLRs per month than all the other camera manufacturers combined. One of the technological highlights was the Electro-Spotmatic of 1971. This camera was one of the first to incorporate automatic exposure. The series concluded in 1973 with the introduction of the Spotmatic F (now incorporating open-aperture metering rather than

8134-513: Was already a general move to smaller 35mm cameras, led by the Olympus OM-1 , so even as the K series was introduced Pentax were working on a new camera line, the M Series which started to appear in 1976. All except the K1000 therefore had relatively short production lives as the M Series took over the Pentax mid-range. The KM, the cheapest of the original three cameras, was almost identical to

8232-519: Was also the first Japanese 35mm SLR. There has always been a close design relationship between the products of Asahi, and those made in Germany (and later East Germany) by a variety of manufacturers, most notably Zeiss Ikon. In the case of the Asahiflex, study should be made of the immediate pre-war and immediate post-war models of the Praktiflex, which could be properly called the inspiration for

8330-521: Was announced on 14 September 2006. The K10D featured a pentaprism viewfinder (instead of the slightly dimmer pentamirror on some previous models), full programmed, aperture and shutter priority modes, and a new Sensitivity-priority mode where the rear dial adjusts light sensitivity and the camera adjusts shutter speed and aperture to maintain correct exposure. Power contacts on the lens mount were introduced to enable Pentax's SDM (Supersonic Drive Motor) for silent focusing. The power contacts also provide

8428-470: 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 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

8526-564: Was entirely manual and resembled the earlier KX in features. The ME Super was an ME with a manual mode. The MG, MV, and MV1 were even simpler versions of the original ME. The ME-F was an early attempt at an autofocus SLR using a special 35-70mm zoom with a motor built into the lens. The Pentax LX model was a tough, professional-grade competitor to the Nikon F3 , the Canon New F-1 , Olympus OM-2 , and Contax RTS cameras. It replaced

8624-434: 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

8722-511: 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

8820-654: Was invented by the Polish engineer Leon Warnerke  – pseudonym of Władysław Małachowski (1837–1900) – in 1880, among 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

8918-470: Was not TTL, but instead featured the typical large selenium mini-lens pattern on the front of the pentaprism. Otherwise the camera resembled the Spot-matic in appearance. While Asahi Optical didn't put the Metallica into production, the concepts of a bayonet lens mount and a metal focal plane shutter were already being discussed internally at the company. In 1966 Asahi Optical showed another prototype called Metallica, sometimes referred to as Metallica II. Gone

9016-652: 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

9114-414: Was released. It still uses the standard K mount but lacks an optical reflex viewfinder. The K-01 quickly became one of the most controversial Pentax offerings, with criticism focusing on the innovative Marc Newson design, which many considered made the camera uncomfortable to hold, with poorly-placed controls, while acknowledging its strong image quality and low-light / high ISO performance. Within months,

9212-403: 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

9310-626: 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

9408-505: Was the background to the development of Asahi Optical's first camera. Asahi Optical introduced its first 35 mm camera in 1952. Asahi was unusual in deciding to start with a high-quality 35mm camera that was not a copy of something else. Its designers were convinced of the inherent superiority of the SLR and so proceeded along these lines. This effort resulted in the Asahiflex I , which

9506-469: Was the cumbersome selenium light meter, replaced with a now standard internal CdS meter. Like the 1960 prototype, the Metallica had a bayonet lens mount, and also featured an improved Copal-square metallic shutter. But the biggest innovation was the fully automatic shutter operation coupled to the TTL meter. The metering system, for the first time in a 35mm SLR, controlled the shutter speed automatically based on

9604-437: Was very difficult to use the camera in a vertical position and taking pictures of moving objects was almost impossible. The small viewfinder on top of the camera was of little use when the photographer wanted to use a 135 mm or 500 mm lens. The problem was recognized by Asahi. In 1957, Asahi introduced the Pentax series, a 35 mm single-lens reflex camera (SLR) camera which was so well received that it influenced

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