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Hardware Chapter Camera Node--Single Lens Reflex 1

2015-01-22  LOFT生活
     Refers to a single-lens reflex digital camera, namely Digital Digital, Single alone, Lens Lens, Reflex reflective abbreviation DSLR.
     SLR means single lens reflex, that SLR (Single Lens Reflex), which is the most popular framing system, most 35mm cameras are using this viewfinder.
     In such systems, mirrors and prisms unique design allows the photographer can be observed directly from the viewfinder image through the lens. Therefore, we can accurately see the film will "see" the same image.
【Term works】
 1. In this system, 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 scene in the viewfinder.
     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.
 3. SLR digital cameras can swap different specifications of the lens, which is a natural advantage SLR cameras, an ordinary digital camera can not match.
 4. Now SLR digital cameras are positioned in high-end digital camera products, so the relationship between the photographic quality digital camera sensor (CCD or CMOS) area is much larger than the area of digital SLR ordinary digital camera, which makes digital SLR sensitive area of each pixel camera is also much larger than an ordinary digital camera, so each pixel will also be able to show more detailed brightness and color range of the photographic quality digital SLR camera is significantly higher than the average digital camera.

【Performance Terminology】
 1. The two main features
 (1) can be exchanged shots with different specifications
     This is the natural advantages of SLR cameras, an ordinary digital camera can not match.
 (2) through the photographic lens viewfinder
     Most of the same bayonet traditional camera lens on a digital SLR camera can also be used.
     Digital SLR camera prices relative to ordinary household digital camera to be more expensive, is more suitable for professional SLR cameras and photography enthusiasts.

 2. The heart of the system is a SLR active mirror, it was placed in a 45 ° angle in front of the film plane.
     Light entering the lens is reflected by the mirror up to a ground glass. To correct this defect, now eye-level type SLR camera mounted on top of a frosted glass pentaprism. This multiple reflection prism will change the optical path of light, the image sent to the eyepiece, then the image is down to just stand around and a correction.
     When shooting, most of the light entering the camera's mirror reflection are up to five prism, almost all SLR camera shutter are located directly in front of the film (because of this shutter is located in the film plane, which is called the focal plane shutter), framing , the shutter is closed, no light reaches the film.
     When you press the shutter button, the mirror flips quickly opened up to let the light path, while the shutter is open, so the light reaches the film shoot. Then, most of the camera's mirror will be reset immediately.
     This necessary action flips the mirror also brings a number of other issues:
 (1) take the picture, the viewfinder will be blocked.
     Because time is blocked just an instant thing, so what is the main problem for this is not immediately reset the mirror it. However, raises a number of contingency issues. For example, in the use of strobe when shooting through the viewfinder will not be able to see the strobe flash device is normal.
 (2) mirror movement
     This needs a quiet place this might be an important issue. Because of the range finder type camera does not block the light path suddenly moving the mirror, this noise is not generated.
 (3) camera shake
     I.e., by operation of the mirror flips caused by the movement of the whole camera.
     Assuming shoot with a shutter speed of 1/500 sec, then do not worry. This shock is not to be noticed. However, if a slower shutter speed to shoot a precise picture of words, such as using a telephoto lens to shoot in dim light, such a shock to the imaging may be problematic.
 3. Use the SLR viewfinder there are still another problem.
     For example, we want to use the f / 32 aperture to shoot such a small, but the aperture f / 32 to allow light entering the lens is very weak, which causes the image seen in the viewfinder is very dim, it may be difficult to focus, or simply unable to perform focusing.
     In fact, SLR solution is quite clever, it will first use the maximum aperture of the lens allows us to complete framing and focus, when you press the shutter, lens aperture shrinks immediately to the preset aperture, exposure to complete the film, completed in exposure moment, will open the aperture to its maximum aperture, once ready for the next shot.
【Article is excerpted from: Web Search】
【Reserved Integrate / Just Reference】
【Translation is by The Network】




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