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【Concept】 Single-lens reflex camera, (Single Lens Reflex Camera, abbreviated SLR camera), also known as SLR cameras. It is a lens through this lens reflex viewfinder of the camera. "Single shot" means the photographic light path and optical viewfinder share a shot, unlike rangefinder camera or dual camera optical viewfinder as an independent lens. "Reflective" refers to a plane mirror inside the camera will separate the two optical paths: When framing the mirror to fall, the lens of the light reflected to the pentaprism, to the viewfinder; when shooting fast lift mirror, the light can be irradiated onto the photosensitive CMOS device on. =========================
【History term】 In 1935, the Soviet Union manufactured the world's first 135 SLR (Спорт, which Спорт Sport English meaning). In 1936, Germany created the first mass production of 135 SLR Jhagee Exakta. 1949, Germany created the first pentaprism SLR Contax S-type (CONTAX S). In 1950, Germany created the first interchangeable SLR viewfinder Exakta VX. 1954, Japan Pentax (Pentax) company released the world's first real-time automatic reengaging mirror SLRs Asahiflex II. In 1958, Germany's first built-in metering out the form SLRs CONTAFLEX. In 1960, Japan created the first high-speed vertical-travel metal shutter SLRs Konica F type (KONICA F), the maximum speed of 1/2000. In 1960, Japan created the first high-speed cross-travel focal plane shutter SLR Canon R2000 (Canon R2000), the maximum speed of 1/2000). In 1960, after creating the first Japanese lens metering (TTL) SLR PENTAX Spotmatic, 1964 years before the success of commercialization). 1966, Japan Minolta (Minolta) company released the world's first full-aperture TTL metering division SLRs SRT-101. In 1971, Japan's Pentax released the world's first full-aperture-priority automatic exposure SLR ES. In 1971, Canon released the world's first full-aperture shutter-priority AE SLR FTb. In 1972, Canon released F-1 Motor, nine frames per second continuous shooting speed was the fastest of the movable mirror SLRs. In 1977, Japan launched Minolta XD (or called XD-7 / XD-11), is the world's first automatic exposure mode with multiple single-lens reflex cameras. In 1981, Japan's Pentax released the world's first autofocus SLR ME-F. In 1987, Japan's Pentax released the world's first built-in electronic flash autofocus SLRs SFX. In 1992, Canon released EOS5, with the world's first pupil focus SLRs (Eye Control) technology. =========================
【Principle term】 --------------- 1. After working system digital SLR cameras, the light reaches the mirror through the lens, refraction and focusing screen to the top to form the image through the eyepiece and pentaprism, we can see the outside of the viewing window scene. In contrast, the general digital camera only (EVF) to see images taken by the LCD screen or electronic viewfinder. Obviously directly see image than by processing the image to see more conducive to shooting. --------------- 2. When shooting DSLR, when you press the shutter button, the mirror will pop up, sensor (CCD or CMOS) in front of the shutter curtain will open, through the lens of the light will be projected onto a light-sensitive photographic original, then after they mirror restitution immediately, the viewfinder image can be seen again. This construction of single-lens reflex camera, determine that it is completely shot through the lens focus, which enables the viewing window is always the same as seen in the image and film, it's shooting range and the actual shooting range is essentially identical very beneficial to visually framing. =========================
【Advantages Terminology】 --------------- 1. It has only one shot, only to use it photography also use it for filming, so the parallax basic problem is resolved. When the light from the subject viewfinder through the lens focus, is inclined to the mirror reflection confocal imaging, and then through the top of the ridge from the "roof prism" (Note) reflection, the photographer can observe the scene through the viewfinder eyepiece, and is down about all the scene the same image, so the viewfinder, the focus is very convenient. Photography, the mirror will immediately bounce back, lens aperture automatically shrink to a predetermined value, so that the shutter is open Film; after the end of exposure shutter closes, the mirror and the lens iris is reset at the same time. ---------------
2. Single-lens reflex camera can freely switch to its support of a variety of wide-angle, focal length, telephoto or zoom lens, close-up lens can also be installed in the lens as needed, plus access extension or expansion bellows connected to the ring. In short all from the viewfinder look at the scene, the camera can shoot down. Simple to use 120 film SLR cameras generally do pentaprism (such as the Great Wall DF-4 type), can be directly on the ground glass viewfinder, focus; in high-end single-lens reflex camera can also put a plan view of the viewfinder (eg Pearl S-201, Nikon F3), so the same can be like a twin-lens reflex cameras viewfinder low tilt or inverted.
This is the single-lens reflex camera twin-lens reflex camera gradually replace one of the reasons. ========================= 【Term Disadvantages】 1. Increase the mirror and pentaprism room after the body heightening, thickened, add weight; 2. mirror bounce the moment there will be a mechanical vibration and noise; 3. Press the shutter button to start the shutter interval is also slightly longer than the other cameras; 4. Use a small aperture lens in poor light environments framing, focus, due to difficulties arising from the viewfinder screen is dark, the focus could easily lead to mistakes. 5. Therefore, some foreign news reporter picked up a head-finder, double shadow coincide focus camera, they think that this camera is compact and lightweight, bright viewfinder focus quickly, easy to candid shots. =========================
【SLR vs dual terminology】 1. The twin-lens reflex camera lens reflex camera later sheets instead, mainly because of the SLR camera and imaging with a small viewfinder parallax, small, interchangeable lenses, film and easy. SLR camera imaging of high quality, the lens can be replaced, can take different shots for a variety of environments. Many more specialized control mode, conducive to the creation of a high level. Can accurately adjust the color temperature, sensitivity by adjusting the shutter aperture combination to achieve a variety of special effects, there are a variety of lenses can be exchanged with 2. dual and specifications are different film SLR Dual Lens of general use 120 film, 135 film SLR general use. Previous 120 film imaging sophistication than 135 film badly, then the extent of 120 film professionals still improve a lot of delicate. 3. dual dual-lens reflex camera, a photography and framing shots were named because of framing and photography are two optical paths, there is disparity, with 120 film is relatively common. SLR is a single-lens reflex camera, framing and photography with the same lens, there is no parallax, 135/120 / Digital cameras have this structure. ========================= 【Article is excerpted from: Web Search】 【Reserved Integrate / Just Reference】 【Translation is by The Network】 |
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