A digital camera, is a use of electronic sensor the optical image converted into electronic data camera. The end-use can be divided into: SLR cameras, card, camera, telephoto camera and household camera, etc.
A, introduction
Digital Camera (English name: Digital Camera abbreviation DCS), is a use of electronic sensor the optical image converted into electronic data Camera. Digital camera with ordinary camera on film by XiuHuaYin chemical changes to record image, the principle of digital camera different sensor is a light inductive charge coupled - {cn: device; zh - Zh - tw: component} - (CCD) or complementary metal oxide semiconductor (CMOS). In the image transmission to the computer before, often after stored in digital in a storage device (usually use flash memory; the floppy and erase duplication CD (cd-rw makes) has rarely used in digital camera equipment).
A digital camera is set optical, mechanical, electronic integration of product. It integrates video information of conversion, storage and transmission unit etc, with digital access mode, with computer interactive processing and real-time filming, etc. Light through a lens or lens groups into the camera, by imaging element into digital signals, digital signal through images stored in computing chip in a storage device. Digital camera imaging element is CCD or CMOS, this imaging element is characteristic of light through, can according to the different light into electrical signals. Digital camera first appeared in the United States, more than 20 years ago, the United States was using it through satellite to transmit photos, later ground to civilian use of digital photography and constantly expand application scope.
Advantages:
1, pictures can see pictures immediately after, thus offered to not satisfied work immediately remake of the possibility, reduce the occurrence of regret. 2, only for those who want to flush the photos, other need not pay the photos can be deleted.
3, color reduction and color range no longer rely on film quality.
4, mode will no longer for film and fixed, photoelectric conversion chip can provide various mode choice.
Faults:
1, because through imaging element and image processing chip changeover, imaging quality compared optics cameras lack administrative levels.
2, because each manufacturer of image processing chip technology is different, the photograph of color and the actual performance objects have different difference.
Four, product classification
SLR cameras
SLR digital camera is refers to single lens reflective digital camera, namely digital digital, performance alone, lens reflex reflective lens, the abbreviation of DSLR. The market of representative type commonly nikon, Canon, BinDe, Fuji, etc. This kind of camera general large size, heavier. Use electronic viewfinder evf models, also be deemed as SLR classes, but generally charging "similar", or indicate whether it is evf point, such as Olympus c - 2100uz, Fuji finepix 6,900 etc. In SLR digital camera work system, light through the lens, reflection to arrive after reflector above the focus and form images, through the screen JieMuJing and pentaprisms, we can see the viewing window outside scenery. By contrast, general digital camera only through LCD or electronic viewfinder (evf) saw the images. Clearly see directly image than through processing see image is more advantageous to the shooting.
SLR digital camera is a big characteristics can be exchanged different specifications of lens, this is SLRS natural advantages, is the general digital camera can't compare with.
Card camera
Card camera menas no clear inbounds concept, only refers to those compact appearance, relatively light fuselage and ultra-thin fashion design is the main measure of this kind of digital camera standards. Including SONY T series, Olympus AZ1 and casio Z series etc all can be classified in this field.
Main features: CARDS digital camera can not calculate encumbrance by carry, On formal occasions and put them in the suit pocket to also won't fall coat deformation; Ladies hands bag never easy to find space crowded under them. On other occasions the camera to jam jeans pockets or simply hang on neck is also acceptable. Although they function is not strong, but the most basic exposure compensation function or ultra-thin digital camera standard configuration, plus area or spot metering modes, these things can be completed in sometimes some photography creation. At least you to picture exposure can have basic control, combined with color, clarity, contrast options, a lot of beautiful pictures can from these were "ace" are approveth not little thing.
Card cameras and other camera distinction: advantage: fashionable appearance, LCD screen, compact fiber thin body, convenient operation. Faults: manual function relatively weak, super-large LCD power consumption is larger, the camera performance is poor.
Telephoto camera
Telephoto digital camera refers to have large optical zoom multiples models, and optical zoom multiples is larger, can shoot the scenery is more far. Representative model is: minolta Z series, panasonic FX series, Fuji S series, kodak DX series, etc. Some lens the longer a digital camera, the internal lens and photographic device mobile space bigger, so zoom multiples are bigger also.
Main features: telephoto digital camera main features actually and telescope principle about, through the lens inside lens moves change focus. When people shooting the distant figures or being photographed do not wish to be disturbed, telephoto will play out. Another is the focal length of the longer the depth of the shallow, and aperture the shallow depth of field effect are same, the shallow depth of field benefit is outstanding theme and throw the background, believe a lot of FANS in the photo are pursuing a shallow depth of field effect, so make pictures out more professional. Some lens the longer a digital camera, the internal lens and photographic device mobile space bigger, so zoom multiples are bigger also. Now digital camera optical zoom multiples mostly in 3 times - 12 times between, can put the 10 metres objects closer to 5-3 meters near -- Also some digital cameras have 10 times the optical zoom effect. Household camcorders multiples of optical zoom in 10 times - 22 times, can clearer photographed 70 meters outside of things. Use barlow can increase camcorders of optical zoom multiples. If the optical zoom multiples enough, people can in front of the lens plus one barlow, its calculation method, a 2 times the increased from lens, set in a originally there is 4 times optical zoom camera, so this set of a digital camera's optical zoom multiples from originally of 1 times, twice, three times, four times as much into 2 times, four times as much, 6 times and 8 times, namely to increase from the lens multiples and optical zoom multiples multiplication income.
Zoom scope the bigger the better? For the camera's overall quality is concerned, actually zoom lens range is larger, the quality of the poor. Super zoom lens is 10 times most frequently encountered two problem is lens distortion and dispersion. Purple boundary conditions are more serious, super zoom lens very easily with wide-angle end produce bucket deformation, while in telephoto end produce pincushion distortion, although lens distortion is inevitable, but good lens will deformation control in a rational range. But in theory, the greater the zoom lens multiples is also more easy to produce the deformation. Of course many manufacturers also to do a lot of effort. Such as usually manufacturer will join in the camera lens aspherical to prevent this distortion generation. For dispersion for manufacturer usually use an dispersion lens to avoid, such as a nikon ED lens. With optical technological progress, current 10 x zoom actually in optical performance should be able to meet the needs of People's Daily filming.
Three, data storage
Currently digital camera video storage formats roughly have the following kinds.
1, AVI file format
Expand called. AVI format is the earliest video, one of the primary specification. Because AVI format without compressing, so for a short video for several seconds AVI file often requires 5 ~ 8MB storage space. Plus, because he didn't have a complete specifications to use AVI format manufacturers make reference, single act out the specifications of the clans yourself there are at least 100 variety above. Though currently popular video playback software, such as: WINDVD, POWERDVD, even AcdSee 3R - 1 etc. Can be shown on up to 60% ~ boasts more than 70% of AVI file. But according to the current situation, MicroSoft Mediea Player 8.0 is compatible degrees best AVI av playback software. At present is most common dynamic image format.
2, MOV file format
MOV is currently the most digital camera manufacturers most often pick one of the animation format. The main reason lies in its streamline compression technology that provides users at low resolutions under good video choice, plus player software QuickTime got an apple computer free authorized the use of its popularity, natural more add. Currently QuickTime 4.12 above version can not only handle video and animation, graphics, text, voice, even 360-degree virtual reality (VR) would not be a problem.
3, JPEG - AVI file formats are
Due to JPEG USES is full-color video standards, with unique distortion compression technology DCT, image data the less important part removal, effectively reduce the file size. Will animation playback capability and JPEG unifies, called MJPEG namely is the abbreviation of are JPEG. The storage of extension is still using AVI to match the dial compatibility. Put software Because of this image specification is simple, occupied memory capacity and small, many do not support synchronization function of digital cameras, radio, for example: CoolPix Nikon 9XX series and some simple video conference with network camera, everyone likes to use such format.
4, MPG then larger - file format
With the increasingly popular, VCD worn jointly MPEG - 1 technical followed by got spread. Although, at present only rarely part of the digital camera to support this specification animation recording (most in Japan are SONY. Its combination with the professional CCD camera plus animation techniques, the synthesis results, compared with DV almost outfights them. MPEG full name is Moving or Group, belong to compare notes on what we've ISO/IEC standard (international standards organization and international electronic technology association) one. MPEG - 1 standard appeared in 1992, was designed to support the first generation of cd-rom playback specifications, transmission speeds up to 1.5-4-0 Mbps per second (megabits, about quite 29.97 FPS), resolution: 352x240. There are three kinds of compression MPEG frame method, respectively (Intra frame I frame), P frame (frame) and B Predicted frame (frame) increase Bi - directional compression efficiency. Through the broadcast program decoding, MPEG - 1 technology makes long time of electronic images can make turn fast, back to take even choose time these actions. By recording files, MPG then larger may also directly copied in VCD, VCD PLAYER to watch. Through
5, ASF - file format
MPEG - 1, at least for the launch of computer world brought two revolution; one is to record long time of electronic files has the function of animation, the other is a search MP3 music is the comprehensive suppression. Because each big record company has always been beset by MP3, therefore in the formulation of a new generation of video technology must be made stricter, not easy be reproduced sound format to replace MP3. Therefore as a leader in Microsoft software to promote the popularization of dedicated ASF format: ASF format is characteristic of image part adopts the latest MPEG4 compression way, voice part then switch on its own r&d WMA format (WMA emphasize its compression ratio MP3 also strong twice, timbre and MP3 close, plus the confidentiality clause and design WMA files use must not be copied as readily as MP3). .
In order to avoid WMA sound copyright dispute, the industry appeared a convert video formats MP3 DIVX format. DIVX to image, MP3 compressed MPEG4 audio compression, and with AVI file format storage! . But due to broadcast DIVX specifications of the image file must download DIVX CODEC, plus DIVX broadcast system resources required considerable high, at least in AMD K - 350 or Pentium II 300 more CPU can smoothly broadcast. In the foreseeable future, unless substantially upgraded digital av IC processing speed, otherwise within short time with this specification will see digital video recording equipment listed.
6, RM - file format
RealVideo is RealNetworks designed for network of development the real-time video playback software, make web producers can on the web site to provide real-time video program. Also, by RealNetworks developed RealAudio, can provide voice on the site of the real-time broadcast. Users can to the following web site for free download RealPlayer software and information. In addition, RM can also support online Stream Line directly playback, without the entire media files downloaded. But because of poor quality of the RM faults can't be settled effectively, the present market condition haven't support RM record of format digital camera. But at present domestic of some low-end digital camera maker has achieved RM authorization, are developing the technology, believe that the future can see the format of the support RM network digital camera.
7, animated GIF format
The GIF strictly speaking, calculate only dynamic pictures show format. Color only support to 256 colored order, cannot recording. Standard specification is divided into GIF87a and GIF89a two kinds, only GIF89a has a transparent background and animation playback capability. Digital camera applications, also only SONY a can directly made GIF CLIP.
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