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"Concept"
Single lens reflex digital cameras, Digital digital, Single individual, the initials DSLR Lens lens, Reflex reflective.
SLR means single lens reflex, SLR (Single Lens Reflex), which is today's most popular framing system, this viewfinder is most 35mm camera.
In this system, the unique design allows the photographer to mirrors and prisms from directly observed through the lens to the image in the viewfinder. Therefore, you can accurately saw the film is about "seeing" of the same image.
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"Works"
1. in this system, after arriving through the lens reflector of light, refraction into the focusing screen and form images above, through the eyepiece and pentaprism, we can see the scenery outside in the viewing pane.
In contrast, most digital cameras can only be via the LCD screen or electronic viewfinder (EVF) see images taken.
Clearly see images more conducive to shooting than by working on seeing images.
2. in DSLR photography, when you press the shutter button, the reflector will bounce up, the sensor (CCD or CMOS) in front of the shutter curtains are open at the same time, through the lens of light projected onto the photosensitive emulsion on the original, and then reinstated mirrors once, again you can see the image in the view window.
Single-lens reflex cameras of this building, it has been confirmed it is taken completely through the lens focus, it can make the viewing window seen in like forever in the video and film, its frame of reference and the actual shooting range largely consistent, greatly facilitates the intuitive viewfinder composition.
3. SLR digital cameras you can swap lenses with different specifications, this is the advantages of SLR cameras was born, are ordinary digital cameras cannot be compared.
4. now SLR digital camera are positioning Yu digital camera in the of high-end products, therefore in relationship digital camera photography quality of photographic components (CCD or CMOS) of area Shang, SLR digital of area far is greater than General digital camera, this makes SLR digital camera of each pixel points of photographic area also far is greater than General digital camera, therefore each pixel points also on can performance out more detailed of brightness and color range, makes SLR digital camera of photography quality obvious than General digital camera.
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"Performance"
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1. the two main features
(1) Exchange of different specifications of lenses
This is the advantage of SLR cameras was born, are ordinary digital cameras cannot be compared.
(2) through the photographic lens viewfinder
Most conventional cameras of the same bayonet lenses on a digital SLR camera can also be used.
Digital SLR camera prices expensive relative to the ordinary household digital cameras, SLR cameras are more suitable for use in professional and amateur photographers.
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2. the activities of SLR system is the heart of a reflector, placed it at a 45 ° angle in front of the film plane.
The light coming through the lens by reflex reflector up to on a piece of frosted glass. In order to correct this defect, now eye-level SLR cameras were installed in the top of frosted glass pentaprism. This Prism the light many times reflect changes of light road, take the image to the eyepiece, just stand around and up and down when the image is correct.
When the viewfinder, are most of the light entering the camera reflection mirrors up to pentaprism, almost all SLR camera shutter is directly in front of the film (because the shutter in the film plane, thus known as the focal plane shutter), when the viewfinder, shutter closed, no light reaches the film.
When the shutter button is pressed, mirror flip up rapidly the way light path, while the shutter open, so the light reaches the film completed shooting. And then, most from your camera mirrors will reset immediately.
From mirrors of this necessary action but also a number of other issues:
(1) the moment of taking pictures, the viewfinder will be blocked.
Because it was blocking the only time an instant thing, so this is not a major problem for immediate reset of mirrors. However, also leads to some incidental issue.
For example, in the use of stroboscopic light when shooting will not be able to see through the viewfinder stroboscopic devices are Flash properly.
(2) mirror movement noise
This quiet place in which may become important issues. Due to range-viewfinder cameras did not suddenly stop moving mirrors for optical path, it will not produce this noise.
(3) camera shake
From the reflector from the action caused by camera movement as a whole.
Assumptions taken with a shutter speed of 1/500 of a second, you do not need to worry about it. This vibration is not to be noticed. However, if you take a picture at lower shutter speeds accurate photos, for example, in the Dim light when shooting with the telephoto lens, this vibration Imaging may be problematic.
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3. Another problem with using SLR viewfinder.
For instance, we want to use f/32 such a small aperture for shooting, Aperture f/32 allows light entering the lens is very weak, which will cause the images that you see in the viewfinder is also very bleak, may make it difficult to focus, or even impossible to focus.
Indeed, SLR solution is fairly clever, it will use the maximum aperture of the lens let us complete the framing and focus, when I press the shutter, the aperture of the lens would immediately shrink to preset aperture, completing the film exposure, at the moment of exposure is complete, open to its maximum aperture, aperture will, and prepare for the next shot.
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【Article is excerpted from: Baidu Encyclopedia】
【Network reprint / Just reference】
【Translation is by Goolge】
