Correct use of digital camera

How to use digital camera correctly? The purchase, use and maintenance of digital cameras involve many aspects of knowledge. For most consumers, digital camera is still a mysterious and high-end product. Below, I have compiled a complete book on the correct use of digital cameras for everyone. Welcome to read the reference!

1, three digital photo formats

The three storage formats of digital cameras are RAW, TIFF and JPEG. Only by understanding the characteristics of these three formats can we correctly choose the storage format when shooting.

First of all, the RAW image format supported by advanced digital cameras is a format that directly stores the image data imaged by the photosensitive elements of digital cameras. Without compression, the quality of digital photos will not be impaired. Moreover, because the original image data of the photosensitive element is stored, the parameters such as positive and negative exposure adjustment, tone curve, white balance and sharpness of the image can be adjusted in the future. The disadvantage is that RAW needs special software to deal with it. At the same time, when shooting, only the JPEG copy of the RAW file specially provided for preview can be seen on the LCD screen of the digital camera, and in order to avoid wasting storage space, the compression of this copy is relatively large and the picture quality is poor. This is also the reason why some digital camera users mistakenly think that the effect of RAW format is worse than JPEG.

If the digital photos taken are used for printing and publishing, only the photos in RAW and TIFF formats with lossless compression format will have ideal effects. At present, most digital cameras support TIFF format. Its advantages are good quality and higher compatibility than RAW, and it will not be limited by processing software. However, the disadvantage of TIFF format is also very obvious, that is, the image file is relatively large and the storage time is relatively long.

JPEG is the smallest of the three formats. If you want faster storage speed and higher software compatibility, JPEG is the best choice. However, it should be noted that JPEG is a lossy compression format, that is, some data of the original image is lost in the compression process, and these data cannot be recovered.

Digital zoom is used to take and store photos in JPEG format. The effect of digital zoom is better than the interpolation and amplification effect of later computer software, but for lossless images in TIFF or RAW format, the effect of later software processing is better than digital zoom.

2. Correct use of RAW format

Advanced digital cameras support the use of RAW image format, but many users don't quite understand how to use it. This original image data storage format is similar to the digital negative of a traditional camera, and it is the preferred format for professional photographers. If you also want to use a SLR digital camera instead of a professional traditional film camera, then you will also need this image format that can preserve the imaging details and data to the greatest extent.

However, to use this image format, special image processing tools and software are needed. RAW file is the original data file recorded by CCD or CMOS photosensitive element when shooting. It is recorded as a set of 8-bit or 10-bit binary data, which only reflects the intensity of light irradiated on the photosensitive unit and does not contain intuitive image information such as color, and is closely related to the hardware. Without knowing the physical parameters such as CCD or CMOS photosensitive cell array and color filter array, it is impossible to convert them into images. Therefore, the image processing tools used to process RAW files need to support your digital camera.

Generally speaking, it is recommended that you first choose the software provided by digital camera manufacturers. For example, if you use Canon's EOS 10D digital camera, you can choose the RAW file browser "FileViewerUTility" provided by the company, so that you can browse the photos taken on your computer and check all relevant camera settings. More importantly, it allows you to adjust the image in RAW format, including positive and negative exposure adjustment, gradient curve, white balance, sharpness and other parameters.

In addition, you can also consider using Photoshop's digital camera RAW plug-in, which supports digital cameras from digital camera manufacturers such as Canon and Fuji.

3. Recover the digital photos deleted by mistake.

When using digital cameras, we store digital photos on storage media, such as CF, SM, SD card and memory stick. In addition, we will copy the digital photos to the computer. Sometimes due to various subjective or objective reasons, there will be misoperation, and useful photos or other data files will be deleted by mistake. At this point, you don't have to beat your chest, whether it is a digital photo stored on a memory card or a digital photo copied to a hard disk, it can be recovered in most cases after being deleted by mistake.

I believe that most users who are familiar with computers have no objection to the recovery of data deleted by mistake on computers, but most users mistakenly think that the data on memory cards are different. In fact, digital cameras follow the DCIM standard, and the data storage format and operation mode on the memory card are the same as when computers operate disk data. Therefore, based on the data recovery principle of magnetic media such as disks, theoretically, digital photos on memory cards are not only recoverable, but also easy to realize, just like digital photos that have been copied to computers. Digital photos on the memory card can be easily recovered by using commonly used data recovery software on computers, such as EasyRecovery, GetDataBack, FinalData, R-Studio, etc.

4. The influence of resolution when shooting.

The higher the resolution, the higher the accuracy of the image. It is a misunderstanding for many digital camera users to shoot with high resolution as much as possible. Theoretically, high-resolution images can be obtained, but digital photos should be recorded in the form of image files. With the improvement of resolution, the number of image files will also increase, and the time for digital cameras to process images will also increase. Therefore, the higher the resolution used, the more processing time and storage space required for shooting. When shooting with a digital camera, the capacity of the storage device is limited. The higher the resolution, the less pictures can be taken. In addition, due to the long processing time, using too high resolution in the snapshot may also miss the wonderful shots.

Even if you don't care about the waste of storage space and the increase of processing time, the choice of resolution should be limited to a sufficient range. Otherwise, when you do post-processing, you will find that the image taken with higher resolution is reduced to low resolution by software, which is similar to the visual effect of the image taken directly with lower resolution, and the definition of the subsequent image seems to be better.

5, the choice of resolution when shooting

At present, most digital cameras have several levels of resolution to choose from. How to decide which shooting resolution to choose? The purpose of the shot image is the main reason that affects which level of resolution to choose for shooting. If digital photos are only used to make web pages, then the resolution is not too high. If they are only used for display on a monitor, it must be remembered that there is a correspondence between image pixels and display settings of the monitor. Therefore, if you want the image to be displayed in full screen on the standard 640×480 pixel display screen, you only need a 640×480 pixel image. If the screen display is set to 1280×960 pixels, the image with 640×480 pixels will only occupy half of the screen space. There is no need to consider the number of pixels per inch, and the display only cares about the number of horizontal and vertical pixels.

If your digital photos will be used for printout, then you need to remember that screen display and printing and printout are two different things. You need to understand these two words and remember the relationship between them. Image resolution describes the total number of pixels (PPI) of an image, and the unit is PPI. What determines the quality of image output is the output resolution of the image, which describes the dots per inch (DPI) that can be generated when the device outputs the image. They are related but not equal, "image resolution ÷ output resolution = image output size". Taking magazine printing as an example, the minimum output resolution is 300DPI, and the resolution of 16 full-page picture is about 3200×2400.

6, the use of white balance

In digital photography, in order to achieve accurate color reproduction and solve the problem that the camera can not correctly identify the colors of light sources with different attributes, it is necessary to set the white balance correctly.

Digital cameras of various manufacturers have automatic white balance and manual white balance. Automatic white balance is convenient, but its accuracy is limited. Therefore, in addition to automatic white balance, digital cameras now have various predefined white balances, such as sunshine, cloudy days, incandescent lamps and fluorescent lamps. But even so, the light conditions in real life are varied, and the correction ability of predefined white balance and automatic white balance is limited for different digital cameras. In addition, when using automatic white balance, it is easy to cause the problem that the color of the previous scene is particularly biased towards a certain color, which leads to the subsequent photos being biased towards a certain color.

Therefore, when shopping, it is best to choose a digital camera with manual white balance function to leave more room for adjustment. Careful observation, repeated guessing and skillful use of the white balance function will take more beautiful photos and bring you unexpected fun.

Don't be too limited to experts or traditional methods of use. For example, most users of Canon G2 digital camera press WB key to switch to white balance setting, select the last manual setting, and then press * key to aim the lens at a large area of pure white object for white balance setting. But in fact, we can set it according to the actual needs, for example, using the white balance function in turn can not only make the sunset glow redder, but also take the same photographic effect as professional photos.

7, the choice of measurement method

At present, almost all digital cameras use TTL photometry to measure light through the lens. The advantage of photometry through the lens is that it can directly reflect the light intensity of the scene, that is, the light is projected onto the photosensitive element through the lens, and then the photosensitive element sends the light signal to the processing chip of the digital camera for analysis. In addition, some semi-professional or professional digital cameras also provide a variety of metering methods for users to choose from. When choosing measurement methods, we must first understand their characteristics.

At present, there are many metering methods for digital cameras, but in fact they can be divided into average metering, center focusing metering and spot metering.

Average photometry takes the average of all the light intensities of a picture as the photometric value, which is characterized by not considering the subject of the picture. For a picture with average illumination, photometry is more accurate, which is suitable for occasions with uniform illumination and weak contrast. There are many methods for data collection and calculation of average photometry, such as Canon's "zoning evaluation photometry" method, which divides the picture into 35 parts for evaluation photometry. In fact, this is also an average metering, but it can make the calculation result more reasonable.

Center-focused photometry is to calculate the values of the pictures in the center and the vicinity of the picture as photometric values according to different weighting coefficients. The center has the largest weight, and the closer it is to the edge of the picture, the smaller the weight. This is a moderate metering method, which takes into account both the overall brightness within the framing range and the fact that the subject is generally located in the central area when shooting, and is suitable for occasions where the subject is prominent and the background needs to be taken into account.

Spot metering is a professional metering method, with the area of the center of the picture accounting for 1% as the metering area. This is an extreme photometry method, which is suitable for situations where the light is complex or the light ratio is strong, and it is necessary to highlight the subject and create special artistic effects.

8. Sensitivity setting

ISO (International Organization for Standards) is the abbreviation of the international organization for standards that sets industrial standards. In the industry standard of film camera, ISO standard measures the sensitivity of film to light. The lower the value, the slower the exposure sensing speed of the film.

ISO standard is also used in digital cameras to measure the light sensitivity of photosensitive elements. The larger the value, the more sensitive the photosensitive element is. In a traditional camera, you can use films of different ISO standards according to the required shooting effect to take advantage of their different exposure sensing speeds. In a digital camera, you can also change the sensitivity of the photosensitive component by adjusting the ISO value.

Improving the ISO value of digital cameras means improving the sensitivity. Due to the improvement of sensitivity, the shutter speed of digital camera will be faster and easier to shoot. However, attention should be paid to it, so there will be some adverse effects. For example, the current intensity after the optical signal is converted into an electrical signal is weakened due to the lack of sensitivity of the photosensitive element, and the noise phenomenon in the dark part or monochrome area of the photo will be more obvious. If you want to get a clear picture, then you can consider shooting with a low ISO value. But different camera sensitivity settings need their own actual experience. It is suggested that you increase the sensitivity step by step when shooting without knowing the camera characteristics.

9, shutter control skills

In photography, the original quality of the captured image comes from the control of exposure. Like traditional cameras, digital cameras control the amount of light allowed to shine on photosensitive elements or films through apertures and shutters. Among them, the shutter determines the time to shoot the image, and its opening time is determined according to the set shutter speed.

Usually the shutter speed range of a camera is 4 seconds, 2 seconds, 1 second and so on. The skill of controlling the shutter is to pay attention to the safe shutter time first. If the camera shakes due to instability during the opening of the shutter, the captured image will become blurred. This is why it is necessary to keep the camera body stable when shooting, and why it is easier to blur the image if the shutter speed is too slow. Therefore, in general, the selected shutter speed is faster than the safe shutter speed, and the safe shutter = 1/ lens focal length. For example, the focal length of the lens is 50mm, and the safety shutter is 1/50 seconds, that is, the shutter speed above 1/60 seconds can avoid the problem of image blur caused by hand shake during shooting.

In addition, when controlling the shutter, special attention should be paid to the time lag of the shutter. The so-called shutter lag is the time between pressing the shutter and imaging the photosensitive element or film. Because the shutter lag of digital cameras is longer than that of traditional cameras, only the shutter lag of top professional single-lens reflex digital cameras is equivalent to that of traditional cameras, and the lag of most digital cameras is 2-3 times that of ordinary traditional cameras. If you use the LCD screen to view the scene, the delay will be more serious. Although the delay is short, it will take a long time for a moving object, and the best opportunity for snapshot photography will be missed. Moreover, the time difference of different cameras is different. You need to know your own camera and do a lot of quick response shooting exercises to avoid the influence of time difference on you.

10, control exposure

Whether it is a traditional camera or a digital camera, controlling the exposure is the key to affect the photo effect. To control exposure, we must first remember the relationship among shutter speed, aperture and ISO sensitivity, that is, if the shutter speed is doubled, the luminous flux of the lens will be reduced by half; With each step of aperture increase, the luminous flux will be reduced by half as when the shutter speed is doubled; ISO sensitivity is doubled, even if the luminous flux is halved, the same exposure can also be exposed.

Now most digital cameras are equipped with "exposure compensation" function. Setting the exposure compensation to+1 means that the shutter speed is slowed down by half or the aperture is doubled. In fact, when using the preset mode provided by the digital camera, the camera will adjust the aperture and shutter speed to double the luminous flux.

Generally speaking, the camera can measure the brightness of the whole picture and determine the best exposure. However, the intelligence of the camera is limited. For example, when shooting white objects such as snow scenes, the digital camera itself will mistakenly think that there is enough light and automatically reduce the exposure, so that the picture taken will be very dark. When shooting a large area of black objects, the camera will also think that there is not enough light.

To control exposure, you need knowledge of exposure compensation, so that you can take photos with the same brightness as expected. Under what circumstances and to what extent compensation is most appropriate, it is ultimately up to your own eyes to master. I can't give you an accurate standard here, but the principle is to increase the exposure compensation for objects with many white and high brightness areas, and reduce the exposure compensation for objects with dark and wide areas.

1 1, infrared shooting effect

In addition to the general flash, other light can also be used for photography, for example, infrared rays and ultraviolet rays. Infrared photography technology has been discussed and applied in amateur and professional fields. If you want to experience it, you can use a high-power infrared lamp to illuminate the subject when shooting, or you can install an infrared filter on other electronic light-emitting devices, so that infrared rays can directly hit the subject and then reflect back to the lens for imaging, thus achieving the effect of infrared shooting. Traditional photography must rely on special infrared negatives, and the preservation, development and transportation of negatives are troublesome, and ordinary users lack experience in this field. However, because the photosensitive element made of silicon is sensitive to the wavelength of infrared light, digital cameras are easier to take infrared photos than traditional cameras.

In addition, if your digital camera is equipped with infrared auxiliary function, such as Sony's F7 17, when using infrared photography, you can not only take ecological photos continuously in low light environment, but also create unique special effects when using landscape photography, and you can also have perspective function, but the perspective ability of infrared photography is not 100%.

12, rational use of flash

Flash is very convenient and suitable as a tool to supplement light source. But generally speaking, digital cameras that emphasize automation don't have strong flash. At best, they program the flash function and provide settings such as "Auto", "Forced", "Red Eye Prevention" and "Slow".

In the "Auto" mode, the camera will automatically determine whether there is enough light in the shooting scene. If it is insufficient, it will automatically turn on the flash to make up for the light when shooting; The "red-eye prevention" mode is to flash the flash once or several times to make people's pupils adapt, and then flash and shoot mainly to avoid red-eye problems in photos; "Forced" mode, that is, whether in bright or low light environment, turn on the flash to flash, usually used to shoot people with their backs to the light source; "Slow" mode will delay the release speed of digital camera shutter. Illuminate the foreground with a flash. If the shutter is slow, such as 1/5 seconds, it will be exposed in a weak light background, and a photo with both foreground and background exposed harmoniously will be taken.

Due to the limited intelligence of digital cameras, it is difficult to determine the effect of flash under different settings. Therefore, in order to get better shooting results, it is necessary to buy a digital camera with an external flash with manual function, and the intensity, size, frequency and times of the flash are determined by the human brain, which can greatly expand the shooting range. Generally, manual control of the flash requires a lot of practice, because a digital camera is used, and more shots can be taken to determine the flash energy. It should be noted that when some external flashlights use low power to reduce the light output, the color temperature will be slightly higher.

13, macro function of digital camera

Macro mode on digital camera is mainly used to shoot objects close to the camera. Macro mode allows you to shoot objects only a few centimeters away from the lens. According to different cameras, the shortest distance to shoot an object is also different. This mode is usually used to improve the focusing speed when taking ordinary photos.

Close range is also called macro shooting. Usually, the button with flowers on the consumer digital camera is the conversion button for macro shooting.

Macro photography is one of the specialties of digital cameras. With macro photography, ordinary scenes can also be made into dramatic scenes. Macro photography is especially good at expressing tiny things such as flowers, birds, fish and insects, and can fully show details. It can also express its creativity at will in topic selection, composition and lighting, unlike taking pictures of scenery, people and folk culture, which are subject to many conditions. Macros are quick to get started, although they are mostly sketches, but they often contain the good intentions of many authors, and they can also be called fine works.

The purpose of macro photography is to show the details of the subject and the subtle parts completely. In macro photography, there is a term that must be recognized, and it is Magnificatlon. Because macro photography is actually like magnification photography, the magnification directly affects the effect of macro photography. Because the magnification is defined by the ratio of the image obtained from the film surface to the size of the object, the magnification is expressed as the ratio. For this reason, magnification is also called "image ratio".

It is often heard that the lens can take macro effects of 1: 1 and 1: 2, and these ratios refer to the magnification of the lens. The value on the left represents the size of the image on the film plane, while the value on the right represents the size of the actual object. When the lens can reach the magnification of 1: 1, the lens can completely project the real size of the object onto the film plane. Let's give a simple example: the area of 135 film is 24 mm x 36 mm. If we use a lens that can completely record the subject with the same area of 24 mm x 36 mm on 135 film, the magnification of this lens is 1: 1. We should remember that the larger the number on the left, the higher the magnification. If the value on the right is greater than the value on the left, the magnification will be smaller.

At present, the macro function of consumer digital cameras is different, some are 10 cm-20 cm, and some can reach 1 cm-2 cm.

For SLR digital cameras, the macro shooting ability is determined by the lens. Now almost every lens has macro function, but the macro function they refer to actually refers to the close-up ability of the lens. Generally speaking, the magnification of a lens must reach 1: 2 or even 1: 1 to be called a macro lens. Macro lens is the easiest macro shooting equipment to use, and users can use it immediately without adding any accessories. Generally, the highest resolution and contrast of a lens are displayed when the focus is at infinity, while the macro lens is just the opposite, and its highest resolution and contrast are displayed when the focus is at close range. So if you want to take high-quality macro photos, you must choose a macro lens.

In order to meet different needs, there are macro lenses with different focal lengths in the market, ranging from 20mm to135 mm. A wide-angle macro lens is often used with a telescopic cavity. 20mm macro wide-angle lens combined with expansion joint can make the magnification as high as 5:1-12:1.

It is often found that the remake photos posted by many friends on the blog are empty. The problem is that the macro function is not used when remaking photos, and the focus is not real in normal mode.

If you shoot flowers in macro mode in Shang Huashi, you will get unexpected results.

14, to understand the differences of computer screens.

Most users who use digital cameras will use computers to process photos, or store and browse photos on computers. But at the same time, the effect of browsing photos on the computer screen is different from the actual output photos, which also puzzles most users.

In fact, due to different equipment, this difference is normal. Do you feel that the images presented on the computer are more beautiful than the photos output by the printer? The resolution of the monitor is only 72dpi, but the displayed image is better than the printer with 720dpi or even 1440dpi. The reason is that the color output on the computer screen is analog. When the image can be displayed in continuous tone, even if the resolution is not very high, the image is still very realistic. But when using inkjet or laser printer to output, the image is composed of ink dots. The printer can only control the presence or absence of ink dots, but can't control the depth change. Moreover, the resolution of printing is different from that of electronic images. With the current technology, it is difficult for printers to print equally accurate ink drops.

Besides, there are many similar problems. For example, photos work normally on a digital camera, but the exposure is a bit abnormal when viewed on a computer screen. This is caused by the difference between liquid crystal display and cathode ray display of digital camera, which is as normal as the problem of printer.

So how should we solve these problems? To solve the printer problem, you need to adjust the color of the computer screen to display the same color as the printer, and learn to calculate the accuracy required for printing and outputting images of different quality (refer to the "Selection of resolution when shooting" introduced above). The LCD display problem of digital camera is relatively simple. You only need to open the image in Photoshop, and you can view it by using the "Levels" in the "Image" menu and "Adjustment". If the color scale is average and the photo exposure is normal, adjust the brightness of the display. If there is a blank area on the right side of the color scale, it means that the photo is underexposed and can be adjusted accordingly.

15, protect Exif photographic information.

Most digital cameras support storing Exif photographic information on photos, which can help us to save shooting data conveniently. When we appreciate digital photos, we can not only recall our feelings when shooting, but also sum up our own shooting experience and improve our shooting level. By studying the photographic information of digital photos and comparing the different camera settings and processing of photos with the same theme, we can better grasp the best camera settings when taking such photos, thus improving our photography level.

Exif information is very useful, but it is also easy to be destroyed. If you use the image file viewing function of WindowsXP to browse your digital photos, the photographic information on the photos will be destroyed. Photographic materials will be destroyed, and once destroyed, they cannot be recovered.

In addition, most computer users like to use general picture browsing software (such as ACDSee) to browse digital photos. However, it should be noted that if you use ACDSee to rotate photos or change the resolution of digital photos, the photographic information of digital photos will also change. Therefore, you need to be very careful when choosing and using software to manage digital photos. If your digital camera manufacturer has its own software for processing and browsing digital photos, you should first choose them, such as ZoomBrowserEX and PhotoStitch of Canon digital cameras.