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"Concept" Double-reverse camera twin lens reflex camera. --Double-lens reflector camera SLR viewfinder camera. Single, dual, refers to the lens, that is, single lens reflex or twin lens reflex. Now we are more familiar with SLR camera, SLR is a lens, double reverse is two lenses. English abbreviation TLR ========================= "History" Double-reverse camera originated from more than 130 years ago, its development process can be divided into two periods, one before the second world war, the second is war. Germany double reverse camera, including the RolleiFlex, Rolleicord and Ikoflex belonging to the former Japan double-reverse camera, like Ricoh double reverse, Mamiya C330, you belong to the latter. --------------- 1. it was stated that double reverse camera shape is a two-tier House of camera initially. This camera is known as the "Reporter", I translate it as "Reporter". It is manufactured in 1872 in London, there are 137 years ago. For such an old camera, we may not be able to imagine now how much time is spent, then do it now appears very simple operation, for example, focus screen adjustment main location, focus, or just replace the cassette, release the shutter, and so on. Of course, when objects to be photographed on the move, is even more difficult. Despite the "Reporter" camera that did not use the mirror device, but it overall looks like the distance we later GM's double-reverse camera style is not far away. --------------- 2. probably in 1880, some London meteorological observations in order to shoot the clouds in the sky, they thought of a way, was placed in the camera a mirror reflection of clouds in the sky, so that the viewfinder when people do not have the old Yang craned days, simply look can be a focusing screen! Don't belittle this improvement, the people set the mirror's first attempt in the camera. Since it is a camera made for shooting clouds, so people called it "cloud," as a great technological innovation is born! On the cloud machines, gear the two lenses are linked up, you can have the synchronized movement of the lens. Moreover, the image on the focusing screen because of the reflector becomes erect, you know, before the mirror, the image can be inverted. Cloud machine, are considered direct prototype double-reverse camera, of course, cloud machine there are some problems, for example the fuselage was too big, it is not practical, but there were serious disparity, you cannot close range photography, and so on. However, in any case, the cloud machine great significance in the history of the camera is will not be denied, because it opens the camera a new chapter of development! ========================= "Principle" --------------- 1. as its name implies, TLR system features two lenses, one directly above the other. For transmitting images to the lens on the film below, and transfer images just for framing and focusing of the lens above. The image seen of it is through the lens, but in fact only the following lens will actually go to the shooting. --------------- 2. the typical TLR cameras using 120 or 220 roll film, have a square of side length 6 cm negatives. When using TLR camera, generally waist flat holding it down and watching the ground-glass viewfinder. See image on the frosted glass is 6x6 cm and images from top to bottom in the right direction, but about the direction is reversed. 2 upon mirror reflection, the viewfinder image is formed. ========================= "Advantage" 1. the traditional double-reverse in the lens of the camera a viewfinder, one for Imaging. However the lens can't replace, if not replace two lenses together, the viewfinder and imaging lens Parallax can be costly. 2. dual lens camera imaging has a characteristic is seen in the viewfinder lens image is often different from the records on the imaging lenses in the film, has a parallax. 3. viewfinder is too much trouble, it is difficult to make adjustments, start the Magnifier view viewfinder. If you use a good DSLR Imaging is about the same. 4. double reverse because the viewfinder when the camera a photographer looking down, so ease in portrait photography course photo is not a natural expression. 5. single lens reflex cameras (SLR) in contrast, double-reverse camera (TLR) one more lenses for the viewfinder, the reflector is fixed, photos during the exposure did not affect viewfinder (SLR cameras were mirror lift and hide the viewfinder screen, images out of sight during the exposure). On the frosted glass film imaging and imaging of exactly the same size. ========================= "Faults" 1. because the viewfinder lens and camera lens is separated from and next to shaft type viewfinder cameras, TLR Parallax problems (that is, not WYSIWYG). Disadvantages of this issue when shooting objects at close range will be more apparent. Therefore some modern TLR cameras viewfinder automatic Parallax compensation device built into the system. 2. comparison with the optical viewfinder, or the Finder, frosted glass on the images is not very bright. 3. you must lumber flat down front of the watch object operation was inconvenient. Modern TLR cameras increase a Polo (Porro) viewfinder eye level viewfinder attachments, you can overcome this drawback. 4. the dual-lens system on its properties, bulky, and replace the lens, you need two cameras simultaneously replaced; For today's fast aperture lens, this is indeed a problem. 5. limited lens interchangeability. If a camera lens replaced, you must also replace the viewfinder lens. Today's TLR cameras typically offer interchangeable double-lens device. ========================= "Double-reverse and SLR camera" 1. twin lens reflex camera is clicked later lens reflex cameras instead, mainly because of the Parallax of SLR cameras with viewfinder and imaging small, small size, convenient to change the lenses, films and so on. DSLR image quality is high, the lens can be replaced, can take different lens for a variety of environments. Many control modes towards greater specialization, conducive to a high level of creativity. You can fine tune the color temperature, speed, can be adjusted through a combination of shutter-aperture to achieve a variety of special effects, there are a variety of lenses can be changed to use, 2. double reverse and SLR film specifications are different Dual lenses generally use 120 film, general use 135 film SLR. Previous 120 film imaging and exquisite degree worse than 135 film, later professional 120 film and exquisite degree also is improving a lot. 3. double-reverse is a dual-lens reflex camera, was named by the respective photographers and camera lens, because the framing and photography are two optical paths, there is disparity, more see 120 film. SLR 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: Baidu Encyclopedia】 |
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