Digital camera FAQ

Questioning: The ordinary fool camera has the automatic printing photography date or the time function generally, my digital camera photographs when why above the picture is unable to print the date? How can make up? 　　

Answer: The majority digital cameras do not support to increase the date directly in the picture. This is mainly because the digital picture supports the Exif information format, has contained the camera automatic production such as parameters and so on photography date, time, aperture, shutter speed, needs to examine the words, only need to read the Exif information using the support the map-read software, is then clear. However, some brand's digital camera support directly increases the date for the photography picture. Everybody may according to need to choose in the function menu, although the increase date writing possibly destroys the whole piece picture the artistry, but I thought that gives the user the option is a better design. Actually, if wants to give writing explanations' and so on digital picture increase the photography date is very simple, we may be connected to use the software, solves through the following period processing. For instance, “PhotoCap” is a section of a well-known digital pictures future period processes the software, what can facilitate is the digital picture ads on the date and other writing? 　　

Questioning: The majority digital cameras use the electric charge pale pinkish purple component (CCD, charge-couple device) to take the image sensing, now also had some products to start to use the CMOS sensor, ask that the CMOS sensor's main feature was assorted?

Answer: First in the manufacture, the CCD image sensor relies on a specialized processing process, causes its manufacture process to be fine and to be expensive. The CMOS sensor's processing uses the majority semiconductor factory production integrated circuit's flow, will therefore use the CMOS chip the system overall cost to be very low, on the CMOS chip may also integrate other functions, for example: A/d conversion, the load signal processing, processing is in vain balanced and carry on the camera control and so on, further reduced the complete machine cost, next when CMOS works to only need to use a power source, compares with CCD in the energy conservation aspect has the deeply big superiority. However, also has the great problem the CMOS sensor to the practical stage: That is the ordinary product is very easy to receive the noise the influence, the image formation quality compares CCD finally to have the great difference. However, Canon Corporation already used one kind of special large-scale CMOS sensor in its digital list counter-product, its image formation quality even good in commonplace CCD.

Questioning: I am the numerical code photography amateur, a while ago had bought a digital camera, I want to ask you to introduce simply digital camera's basic structure is what kind of? 　　

Answer: The digital camera is mainly composed of following several parts: First is the CCD image sensor, is equal in the traditional camera's light sensitive film. Another important part is imagery processing special-purpose DSP, for instance the CANON digital camera uses imagery processing chip DIGIC, uses in carrying on work and so on image compression, transformation, filter, revision, is the camera “the cerebrum”. In addition has other special-purpose controllers, manages the camera operation, and completes the memory stick the read-write function, as well as filing system's management and so on. Also in some piece of EPROM chip is preserving camera's Firmware (firmware), quite in the computer motherboard's BIOS chip, or puts in order the Taiwan camera's operating system, usually may carry on the promotion. As for the fuselage and the lens module, including the automatic focusing system as well as the shutter control system and so on, are not big with the traditional camera difference. 　　

Questioning: I am the numerical code photography beginner, although has used the highest resolution hypothesis, but photographs the picture somewhat was still slurred. Moreover makes in the good picture to have many dot frequently, ask the reason what in? 　　

Answer: Whether the picture does photograph clearly with you time establishes the resolution does not have the direct relation. Many situations can cause the picture to be fuzzy, for instance when the optical fiber is not good, the camera vibration will cause the picture to feel weak, may through enhance the aperture and the ISO hypothesis, will raise the shutter speed as far as possible, when the photograph should better use the trivet, or will put the camera to the table and so in the fixed object, when necessity should better use the flashing light. The focusing pattern or the focus choose improper, also creates the picture fuzzy substantial clause. In addition the lens sully will create the fog which the camera will lay out, please use the special-purpose clean lens to use the paper clean lens. As for the picture in dot (noise spot), usually is because the optical fiber is too dark or photosensitiveness hypothesis is too high creates, this is the question which the ordinary digital camera overcomes with difficulty. The noise spot production usually is because in the CCD module “the electrode dark current” creates. The dark current is refers to does not have the electric charge quantity which in the incident light situation CCD still had, theoretically the dark current should be a zero, but actual is unable to achieve, its intensity will advance along with the temperature increases (increases every time 10℃, noise spot quantity will possibly increase 1 time).

Questioning: Last year I have purchased a digital camera, uses in the process often to appear is unable starting or presents the automatic shut-off the situation, ask that is how a matter? 　　

Answer: The possible reason to be many, fixes camera own breakdown, usually is because of the power supply aspect question. If the digital camera in the use process the automatic shut-off, you first should think that suddenly the battery electric power is insufficient, the digital camera is consumes the electricity wealthy and powerful family, insufficient closes because of the battery electric power the phenomenon appears frequently. If after having replaced the battery, the digital camera is unable to open, but you discovered when the camera is quite hot, that is because the long-term usage camera time is excessively long, creates the camera overheated protection, but automatic shut-off. Regarding north user, because the winter outdoor temperature is too low, causes the battery to expire frequently is unable starting. Moreover the memory stick damage or the installment are not normal, also possibly causes the camera to be unable to use normally, may the first formatted memory stick. In addition must pay attention to memory sticks and so on SM, SD to have writes the protection the question. 　　

Questioning: I discover inside the digital picture frequently the scenery and the eye saw the scenery color has had the change, sometimes is red, sometimes yellow. Especially indoor and the night photographs the picture, frequently leaning the color to be serious, ask why this is? 　　

Answer: This is mainly because is in vain balanced has not adjusted creates. The digital camera white balance adjustment function and the traditional camera add the color temperature to transfer ray filter's function are similar, the goal achieves the accurate color return to original state, is only digital camera's color temperature selects the circuit setting method, changes red, green, the blue three primary color proportion of mixture depending on the electronic circuit, the many color components revises the optical fiber. Usually digital camera's automatic white balanced function can guarantee the color returns to original state accurate, but photographed under some complex conditions is very difficult to say. We may use camera's white balanced to come the accurate adjustment from the definition function, this kind of pattern's white balance adjustment is lets you photograph the camera alignment the scene white the object, however the second half presses down the shutter, this time, under opportunity automatic recording this kind of optical fiber the white condition, rests on this value, might correct carry on under the following photography to the color returns to original state.

Questioning: I photograph the digital picture has bright or the dark situation frequently, ask why the digital camera will present the light measuring fault the situation? How to carry on the atonement? 　　

Answer: The digital camera automatic light measuring is determines according to “the standard ash”, is the supposition light measuring region reflection rate is 18%, carries on the light measuring through this proportion to determine afterward the aperture and shutter's value, 18% this value origin are the middle accent reflection performance decides according to the natural scenery, if selects a scene in the picture the white tone majority, by now if photographed according to the camera automatic light measuring determination's stop value, the photography obtains the picture will be owes the insolation the picture, the white background looks like will appear becomes gray, therefore the photography reflection rate will be bigger than 18% scenes, needs to increase camera's to make public compensation value,Otherwise if the photography reflection rate is lower than 18% scenes, for example the black background, lays out the picture will often meet the insolation, the black background will also have turned the gray, therefore the photography reflection rate will be lower than 18% scenes, needs to reduce to make public. Said simply is “Bai Jiahei reduces”. Although the digital picture may adjust to make public through later period digit darkroom processing, but regarding to make public excessive picture, the shadow detail and the level already completely lost, if wants to adjust is quite difficult, but if owes the insolation serious picture, after revising to make public, will present many noise spots, the detail will also have the loss, will therefore let the photography the picture have correct to make public as far as possible. 　　

Questioning: The computer can only demonstrate 24BIT the entire color JPEG document, i.e., digital camera, so long as disposes 8BIT a/D switch to be able to meet the needs, but why can use the 10BIT above switch? 　　

Answer: The reason has the following several points: First, the upscale digital camera usually uses the RAW form preservation photography the picture, RAW may imitate under the share record photographs when all primary data, gets rid of the JPEG specification the fetter, lets the color and the picture nature performance achieves perfectly. Second, increases when the merge digit phantom computation the reference data, in the partial digital camera's DSP procedure has the enhancement resolving power function, this procedure mainly refers to performance of neighbor of picture element the sample picture element, makes statistics to become. Therefore, the BIT higher A/D switch has the more sample parameters, the relative merge calculates 24BIT the JPEG document's performance is better. Therefore digital camera each red, green and the blue color output must achieve above at least 10BIT (1024 gray scales) to be only then good, at present mostly disposes 12Bit a/D processor. The individual high-grade product has achieved 14BIT.

Questioning: I want to ask that which how many kinds enhances CCD the ISO photosensitive ability the method to have? Whether moreover the CCD to make public latitude can be more than the traditional film difference? 　　

Answer: Uses the fixed CCD achievement to be photosensitive the module the digital camera, is unable the traditional camera to choose the negative to change into equally likely compares Gao Huojiao the low photosensitive ability. Must enhance CCD ISO the ability usually to have two methods; first, simplifies the picture element signal enhances ISO from specific region CCD on, because CCD is unable in physics to increase the photosensitive area, simulates the greatly photosensitive area through the union matrix in processing the way, therefore ISO more takes a higher position must cut the resolution relatively. Another method is through the specific signal enhancement electric circuit, obtains the reasonable to make public performance according to the data operation, but will usually be following the noise production. Therefore the digital camera biggest ISO value is mainly is decided high by may accept the signal-to-noise ratio (S/N). Under accurate to make public, CCD will be able to catch the broad phantom tone scope compared to the traditional film. Ordinary CCD may record the 250:1 (8 levels of apertures) about high contrast scene. Upscale FF the CCD system may process nearly 1000:1 tone scope. However, outputs finally on the photographic paper the phantom can only reappear the 32:1 or 5 level of aperture tone scope approximately. 　　

Questioning: I planned that buys a digital camera, mainly uses in the scenery photography, ask whether the market 10X big focal variation product is now appropriate? How to determine the digital camera focal distance the rationality? 　　

Answer: The long burnt digital camera is really having many unique merits, for instance can photograph the very far object, moreover may photograph the background empty feature article picture. But speaking of the photography scenery, wide-angle is most commonly used. Wants the record daily life the intravenous drip, wide-angle can also better competent this work. But in the present market's long burnt camera, its wide-angle focal distance usually about 38mm, speaking of the ordinary family user and the affection scenery photography's user, such Jiao Duanbing did not calculate that is too reasonable. Therefore looked from yours demand that suggested you choose have wide-angle lens' digital camera. The camera wide-angle end should below 28mm, in the market conform to the request product at least to be many now, even had the product wide-angle end to achieve 24mm, very suitable to use in the scenery photography.

Questioning: Ask that the ordinary digital camera focus number are quite why many? Even can achieve the free choice focus, which advantage more do focuses have? 　　

Answer: Regarding the list counter-camera, more focuses and the focal point choice scope means the soaring price. This is by the list counter-camera structure decision, its focusing module is independent, to guarantee high speed focusing, may choose the focusing scope and the position is limited. But the ordinary digital camera focusing way is examines on CCD to assign the region the image formation, completes automatic focusing through the phase analysis, therefore CCD any position, any size's region can take alone theoretically carries on analyzes and focuses, therefore above 5 spots the focus product is not infrequent, some products even may the free choice focus. After for instance Canon 2002 entire line product nearly has also had the AiAF ability, namely may in the screen central majority of region free migration focus. In order to pursue the nimble creativity, the photographic expert will not photograph the main body to put in the picture dead center frequently to come the composition stereotypically, can the free choice focus, give each kind of innovation the composition to bring enormously convenient, regardless of the main body in any position, may move the focus, will carry on the composition wholly absorbed, but does not need to divert attention for focusing. 　　

Questioning: I am the famous digital photography amateur, is long the time to go out frequently to photograph, planned that buys one “the digital companion” to save the picture, ask how should choose? 　　

Answer: At present in the market “the digital camera companion” the product type are many, majority can only make the memory picture to use, but some products already started to provide the colored LCD display monitor and more functions, some products were already not in the pure significance digital camera companion, but may also use for to listen to music, to look that the movie, plays the game and so on. 　　Pure “the digital camera companion” is doomed is the transition product, suggested that you purchase the multi-purpose products, but this kind of product price is usually expensive, therefore may also consider the purchase second-hand pocket-sized notebook. But in fact now the memory stick price reduced many, two 1GB CF cards or the SD card price thousand Yuan, may save several thousand pictures, can definitely meet the ordinary photography need, “digital camera companion” the function was not very big.

Questioning: Now many more specialized digital cameras will provide will have photographed the picture preservation will be the RAW form choices, ask that the RAW form had is assorted the characteristic? 　　

Answer: In the former digital camera, the image storage mostly uses TIFF and the JPEG two kind of patterns. Although the former may not lose the preservation pictorial information, but the encoding method is special, moreover the document volume is quite huge, occupies the space very much. The latter after the compression, has sacrificed the partial pictorial information during reduction document volume's. But the RAW file memory pattern, will come from image sensor's primary information to record, does not undergo any white balanced, the gamma adjustment and the dynamic alignment process. Not only has left behind the very rich space for the later period imagery processing, moreover the document volume is small. This technology obtains the market approval and the application rapidly. Some products also used in the RAW document to inlay the JPEG document the new technology. The user presses down one time the shutter, can simultaneously preserve two types the documents. 　　At present, RAW already became one kind of open form, not only the digital camera manufacturer has provided RAW document processing and the conversion routine for the user, mainstream imagery processing softwares and so on PhotoShop also has the related plug-in unit to process the RAW document. 　　

Questioning: I plan before 51 to purchase a digital camera, I want to ask when selects and purchases the digital camera, which questions specifically should pay attention to? 　　
Answer: Looked the first packing is very old, has the open trace, if has obviously opens the trace, the very possible this machine to have already been chosen, then looks at the outward appearance. Has a look to have the scratch, including lens, LCD, EVF and outer covering and so on, but also has is inspects the fitting is complete. Then may the simple test shot, and looked carefully LCD and EVF do have the bad spot. As for CCD on bad spot, then must be careful. Because on DC is very ugly clear CCD directly whether to have the bad spot, needs to induct the picture PC to look again. Because CCD makes in the craft question, the regular session has certain flaw time, displays is not bright for some image point, or forever is shining. The CCD bad spot may use the software to carry on the test, what compared with is famous is “Deadpixel”. 　　

Moreover the lens physics caliber is also must consider that has heavy-caliber, the many piece of groups, to contain the aspheric surface, the ED lens and the multi-layered coating's high grade lens is the upscale numerical code digital camera's important disposition.

Questioning: The digital camera has been now getting more and more popular, I want to ask that compares with the traditional camera, what characteristic do digital camera's lens have? How to carry on the protection? 　　

Answer: First is ordinary the digital camera, because the image formation component is smaller than a film by far, therefore is higher to lens' resolution request. The example is absorbed to some determination the body, the horizontal direction needs 100 picture elements to be able to reappear its detail perfectly, if the image formation width is 10mm, then optics resolution is 10 /mm lens can be competent, if the image formation width is 1mm, then requests lens' optics resolution to above 100 /mm. Moreover because CCD is quite sensitive to infrared, must therefore behind the lens increase specially infrared filters the mirror, lens' coating way is also different. The camera lens are very tender and delicate, must therefore certainly protect carefully. If only has a dust, suggested that do not scratch, usually does not affect the image formation. If has the hand imprint and so on, suggested that uses to blow the balloon first to blow down the above dust, then scratches gently with the lens pen in above. The long time does not use should better install the camera to the moisture-proof airtight container, avoids the mirror head length mildew. 　　

Questioning: I photograph some digital picture its edge presents the distortion frequently, ask how the digital camera lens' distortion is a matter? How to avoid when as far as possible the photography distortion production? 　　

Answer: All optics camera lens have the distortion the question, the distortion belong to the image formation geometry distortion, it is as a result of the focal-plane in the zones of different the picture distortion metamorphism which different forms to the phantom magnification, this kind of distortion's degree from the picture center increases progressively in turn to the picture edge, mainly reflects in the picture edge obviously. Is especially serious regarding the zoom lens distortion's question, generally when wide-angle end photography, often will cause the picture edge outward bulge, will call it the barrel distortion; When with dolly out end photography, the picture edge will indent inward frequently, calls it the pincushion-shaped distortion. 　　

The distortion will cause when the image formation picture distortion, when the majority the slight distortion will not have to the picture quality affects too greatly, but certain applications will be quite possibly sensitive to the distortion, for instance will rescreen the material, the photography building and so on regular object, hoped that the distortion do not be too serious, will otherwise twist the photography material object obviously the geometry characteristic. In order to reduce the distortion, we when photography avoids using the lens focal distance as far as possible the most wide-angle end or the most dolly out end, and uses the small aperture. Besides the distortion, the camera lens also possibly have other each kind “the aberration”, so-called “the aberration” is the optical fiber through digital camera's lens when the focal-plane the image formation, will have each kind of distortion, causes phantom which the focusing will form each kind of deviation which will produce along with it. Looks like difference many types, mainly has the distortion, the spherical aberration, the astigmatic aberration, the bright difference, the curvature of field and the chromatic aberration and so on, they will distinguish to affect in the different angles the image formation quality.