In the early days of the camera industry, the camera products mainly made by hand were mainly influenced by the painting black box, and the products with the coaxial viewing mode of wool screen occupied an important position.
However, the use of screen framing is greatly limited. On the one hand, in the early stage of the development of photosensitive materials, enough ambient illumination is needed to take pictures; On the other hand, the rough screen image is easily disturbed by external stray light when framing, which leads to contradictions. This contradiction finally inspired the change of framing mode, and paraxial framing is the most thorough product of this change.
there were several types of early paraxial cameras. Viewed from the structure of paraxial viewfinder, the simplest one is called frame viewfinder, which can be installed on any coaxial viewfinder as an additional viewfinder.
because the framing viewfinder is easy to make and its framing accuracy is basically acceptable when shooting scenes at a certain distance, there are many products equipped with framing viewfinder in early cameras, such as Chambre Automatique produced in France in 186 and Eka produced in 1924.
another viewfinder device with a lens on the basis of a frame viewfinder is called Newton viewfinder, which consists of a negative lens (also called concave lens) and a frame. The feature of this viewfinder is that it can be made much smaller when the same field of view is obtained, and it is possible to get a brighter viewfinder with good lens material.
Le Pascal produced in France in 1898, Ernemann Jropical produced in Germany in 194 and Ensign Cupid produced in Britain in 1922 are all cameras with Newton viewfinder.
As another kind of paraxial camera, the dual-lens reflex camera appeared in the second half of 19th century. Its principle is to image the scene on a rough screen with an angle of 9 degrees between the optical axis and the reflector through one or a group of positive lenses (also known as convex lenses), and the framing optical path is vertical. Because the framing lens and the photographic lens are axially parallel and adjacent, the framing error is greatly improved, which is very prominent, so it is quickly popularized.
For example, Kinegraphe produced in France in 1887 and Krugener Simplex produced in Germany in 1889 are the early products of dual-lens varieties;
At the same time, reflective viewfinders with the same principle as dual-lens reflective cameras were also widely used, such as Le Royal Detectif o Ultime Special produced by Belgium in 1893 and Folding Mahogany Rodolphe； produced in 193;
bright viewfinder is a variant of reflective viewfinder, which was popular at the end of 19th century and the first half of 2th century.
The main difference between it and the reflective viewfinder is that it uses a positive lens instead of a wool screen, so that a spatial image of the scene can be obtained, and the viewfinder becomes very bright. However, the change of eye position often affects the viewing range, and often causes the feeling of eye discomfort. Therefore, the bright viewfinder was mainly used as an additional viewfinder later. The No.1 Folding Pocket camera produced by Kodak Company in 195 is one of many products that use bright viewfinder.
this bright viewfinder in turn paves the way for promoting a simple dual-lens reflex camera.
The compound framing device is another milestone in the development of early paraxial framing cameras. It installs two or more paraxial viewfinders on one camera, providing various framing methods. The biggest feature of the composite viewfinder is that it gives users more choices. For example, Newton viewfinder and bright viewfinder are combined on the camera to provide two framing methods: head-up framing and waist-up framing;
or combine the frame viewfinder and bright viewfinder on the camera to provide the same framing requirements.
the appearance of composite framing device has a certain influence on the design of advanced products in the future. For example, Plaubel Makina III D produced in Germany in 1949 evolved this classical composite framing device, although the framing technology has been greatly improved during this period.
In fact, the early paraxial cameras mostly provided some necessary framing methods, while the beauty, convenience and miniaturization of the camera will be the next thing. At the beginning of the 2th century, with the continuous progress of optical technology, the development of paraxial cameras entered a new historical period. The types of optical viewfinder began to improve, and the paraxial ranging device was developed and integrated into the viewfinder. Because paraxial framing avoids the use of photographic lens, the design of camera lens, especially wide-angle lens, can adopt the actual field of view angle instead of the equivalent field of view angle, thus simplifying the lens structure relatively. With the continuous maturity of paraxial framing technology, the miniaturization of cameras has gradually become a reality.
People have an experience that when galileo telescope is used in reverse, they can see bright and reduced scenery images. Don't underestimate this experience. This anti-Galileo principle provides sufficient resources for the development of optical viewfinder. In fact, if a positive lens or a group of equivalent positive lenses are added to Newton viewfinder as eyepiece, the inverse Galileo viewfinder will be formed. Of course, the reasonable inverse Galileo viewfinder needs to be recalculated. Because the inverse Galileo viewfinder is smaller and brighter, it has been widely used in cameras with various paraxial framing methods since the 192s. Inverse Galileo viewfinder is a major revolution of optical viewfinder, which guides the development direction of optical viewfinder in the future.
Leica, the first epoch-making camera product in the 2th century, represents the outstanding achievements of paraxial cameras. When designing Leica cameras, oskar barnack focused on small, lightweight, unique metal body and reverse Galileo viewfinder, which became important symbols of Leica's initial products.
Later, in order to meet the needs of photography, Leeds Company introduced a series of special lenses for Leica cameras and corresponding external viewfinders, which greatly expanded the application scope of Leica cameras and became a model of small cameras.
However, the inability to achieve optical ranging is still a defect of early Leica products. Therefore, it has become a task for Leeds Company to produce a suitable ranging device. Fortunately, Leeds Company will soon produce a small range finder that can be inserted into the chajia.
after Leica II, the range finder is integrated into the fuselage, but the independent range finder can still be used as an accessory, which is not limited by the lens variety.
The prestigious Zeiss Company has also made outstanding achievements in the field of camera manufacturing. Its products cover a variety of specifications, ranging from dry-plate cameras to various film cameras. In order to curb the expansion of Leica products in the field of small cameras in business, Zeiss has spared no effort to develop competitive products. The first targeted product is Contax I, which pioneered the metal rolling shutter with a speed range of 1/25-1/1 seconds and a B door. With the fast Contax port technology and a series of lenses and accessories, Contax camera became the main force that rivaled Leica products at that time.
Subsequently, Contax II and III, whose viewfinders are equipped with linked range finder devices, came out one after another. They are both excellent products in paraxial cameras, and their firmness is also quite excellent.
especially in the Contax III camera in 1936, it integrated selenium exposure meter into the camera body, which was not available in Leica cameras at that time. Leica cameras can only get the corresponding functions through the independent exposure meter in the form of accessories.
Dual-lens reflex camera is an important branch of paraxial camera, which uses the viewfinder lens to simulate the photographic lens to capture the scene image, providing a visual reference close to the actual intake range.
the prototype of lulai in p>1929 laid the development direction of modern dual-lens reflex camera. However, it is not the only direction. There have been many amazing creations of dual-lens reflex camera in the 2th century, such as Superfekta folding dual-lens reflex camera produced in Germany in 1932. The design idea of this camera reflects the attitude of product designers to aesthetics and the bizarre way of thinking.
Since then, the dual-lens reflex camera with 135 film has also occupied a place in the development of small cameras. The most representative is the Kangtai Flex camera published by Zeiss Company in 1935 with the experience of Contex. It not only directly adopts the longitudinal rolling shutter focal plane shutter that Contex shows off in the world, but also can change the lens, and there are a variety of paraxial viewing methods to choose from. The biggest feature is that the most advanced selenium exposure meter was built in the fuselage at that time. This built-in exposure meter technology has had a great impact on the famous Lulai products in the future.
in fact, this unprecedented product would have developed more perfectly if it had not been for the influence of the war. In addition to Kangtai Flex dual-reflex cameras, other structures of 135 dual-reflex cameras are also coming out. Like Meikai Ref No.2 made in Japan in 194, this is a double-reflex camera with horizontally arranged lenses, which is quite distinctive; In 1959, Germany also produced an Agfa Flexilette camera, the main structure of which is closer to that of an ordinary paraxial camera for head-up viewing.
however, all the products with this new idea have not become mainstream varieties, perhaps they are too much, and they are just a flash in the pan in the history of camera development.
However, in any case, the paraxial camera has developed into a huge product system before 195s, and its complete specifications and various types are incomparable to coaxial cameras (including Mao-screen framing cameras and SLR cameras). In addition to ordinary cameras and special cameras (including spy cameras), paraxial products are also at the forefront in miniature cameras. Typical examples are Mikroma produced in Czechoslovakia in 1949 and Golden Ricoh "16" produced in Japan in 1952.
The copying camera is the world of paraxial products, from the imitation of books, watches and guns in the last century to the imitation of lighters and pens in this century, all of which show the superiority of paraxial structure. In fact, until the large-scale application of zoom lens, paraxial camera has been the mainstream product in the lighting market. Since the 195s. In 195, the quality of Japanese cameras began to attract the attention of the United States. The New York Times published the "Test Report of Nikon Camera and Lens", which reported the performance characteristics of the camera and attracted the attention of all countries in the world. This period coincided with a large number of Japanese paraxial cameras, such as Arco35 in 1952, Rich Ray6 in the same year, Mammy and Press Van in 1953 and so on.
In fact, Japan paved the way with paraxial cameras and is rapidly becoming a new camera producer in the world. Japan's move has attracted the attention of West Germany, an old camera producer in history, which can only cope with the changes in the international market by introducing high-quality new products.
in p>1954, while the Japanese were improving various products, the epoch-making Leica M3 camera was published in West Germany.
M3 adopts a series of brand-new technologies, which pushes the paraxial camera of head-up view to a new height. For example, it has built-in equal brightness frame framing and parallax automatic compensation mechanism; Automatic reset film counter; Torque type sheet conveying wrench; And the newly designed single-axis non-rotating shutter speed-regulating disk, which is characterized by no longer rotating when the shutter moves, and so on. The application of these new technologies provides a more comprehensive reference entity for the future development of cameras.
in p>1957, Nikon SP camera, which borrowed M3 technology, came out (fig. 36). It adopted the same single-axis non-rotating shutter speed-regulating wheel and exposure meter linkage mechanism as Leica M3, as well as an improved viewfinder. When using lenses with different focal lengths of 28-135, different visual fields appeared in the viewfinder, which greatly facilitated users. At this point, the paraxial camera with head-up framing mode has developed to a new height.
in 196s, paraxial cameras further developed towards miniaturization and specialization. The camera R&D center began to shift from Germany to Japan. Japanese products take electronization as the main goal of camera development, and have successively popularized CdS and SPD photometry technologies, and first completed the automatic exposure function with the participation of semiconductor technology on head-up camera, and published a large number of cameras such as Jasika Electro 35. These popular cameras have played an inestimable role in promoting the development of the photography market.
On the other hand, professional-grade high-end paraxial cameras such as Mamiya C3 stand out and form a new market structure.
in the 197s, Japan vigorously developed SLR cameras. Due to the moderate prices of a considerable number of products, paraxial cameras began to lose their previous position in the civil field. Although there are still a large number of popular head-up cameras, the golden age of paraxial cameras is disappearing. The appearance and continuous improvement of the anti-Galileo viewfinder have indeed cleared the way for the development of the paraxial camera, and the optical ranging device on the paraxial camera has laid the foundation for the development of the autofocus camera. In fact, the application of semiconductor components has greatly improved the automation of cameras. At first, the table-controlled automatic exposure mechanism shines brightly on the paraxial camera, that is, the paraxial camera with program exposure mode appears again. However, among all automatic modes, the most historic one is the occurrence of autofocus technology.
In p>1977, Konica C35AF camera in Japan took the lead in introducing the double-image symmetrical photoelectric focusing system, which realized the automatic focusing of the camera. The optical theory of this system comes from the double-image focusing device on the advanced head-up camera. It reflects the image to the AF sensor through the mirrors in two ranging windows, compares the contrast of the two images, and changes the deflection position of one of the mirrors. When the contrast of the two images is completely consistent, the central system of the camera sends an instruction to the focusing server to complete focusing. This analogy auto-focusing theory once had an influence on the research and development of SLR camera auto-focusing. In history, there have been several products similar to Chinon)CE-5 AF camera, which use the paraxial auto-focusing system on the lens to operate the lens of SLR camera and complete the auto-focusing. It can be seen that the automatic focusing mode initiated by Konica C35AF paraxial camera finally changed the camera's appearance, and since then, intelligence has become the main direction of camera research and development. The influence of SLR cameras on the market share of paraxial cameras in the 197s is obvious. Besides the price factor, the main reason is that paraxial cameras can't use zoom lenses like SLR cameras, which greatly reduces the convenience. After Asahi Optical Company,Ltd.,Tokyo. introduced the zoom paraxial camera in 198s, the anti-Galileo framing device, which can continuously change the field of view, was widely used in small paraxial cameras. The paraxial camera with head-up framing mode has entered the era of automatic focusing and electric zoom. Zoom head-up viewfinder has become the mainstream of popular products, and the sales of head-up viewfinder have started to rebound significantly, resulting in the situation that SLR products and paraxial products are equally divided in market influence. The emergence of APS has further stabilized this situation.
in the late 199s, with the help of traditional technology,