Traditional Culture Encyclopedia - Photography and portraiture - What are the simple ways to use a home digital camera?
What are the simple ways to use a home digital camera?
There is no difference in optical principle between digital camera and traditional camera. Both of them form inverted and reduced (or enlarged and equal in size) object images through the lens. However, in the specific imaging, it is different because of different photosensitive media. Traditional cameras use photosensitive chemical media based on silver iodide distributed on film. Digital cameras use CCD as the photosensitive medium for recording images, and CCD records the visual characteristics of objects through different charge distributions caused by different illumination. The digital image generated by CCD is transmitted to another internal chip of the camera. The chip is responsible for converting the image into the camera's internal storage format (generally compressed image format, such as JPEG format). Finally, the generated image is saved in memory. The image obtained by a digital camera is actually a collection of numerical values, which can be directly downloaded to a computer for processing, without buying film, and the shooting effect can be seen at any time when shooting. If you are dissatisfied, you can immediately retake it. Compared with traditional cameras, it has many advantages, such as cost saving, digitalization convenience, and reduction of false shooting.
Second, technical guidance.
1, CCD and pixel
For digital cameras, CCD charge couplers are used to sense light. The so-called pixel is the photosensitive element on the CCD. The number of pixels is directly related to the clarity of photos taken. The more pixels, the clearer the image. Basically, the pixels of a digital camera directly determine the maximum resolution of the camera, that is, the product of the resolutions is equal to the pixels of a CCD. For example, the physical pixel of DC240 with 1.3 million pixels is 1.344? 97 1, and its maximum resolution is 1280? 960。 However, there are exceptions. EPhoto 1680 by Agfa has only 1.3 million pixels, but the resolution can be improved to 1600 through its patented interpolation algorithm built into the camera. 1200。
If you take photos and browse on the computer, you can choose the image size of1m. If you want to print photos, and it is more than seven inches, I suggest you use more than 3 m. If you want to enlarge photos larger than 12 inch, you have to choose an image size of 5 ~ 7m. A 7-megapixel camera can take high-quality photos of 24~~30 inches at most.
When shooting, if there is no photography foundation, I suggest you use automatic file instead of manual M file.
2. memory.
The difference between a digital camera and an ordinary camera is that the photos it takes are directly stored in the camera memory. Just like the film has a capacity of 36 sheets, there is a capacity limit for storing objects, but the specifications are much more.
The number of photos that a digital camera can take depends not only on the capacity of the memory used, but also on the resolution and compression ratio of the photos taken. Because the image file sizes produced by different resolutions and compression ratios are different, the number of photos that can be taken in the same capacity memory is also different. In the case of high resolution and high image quality, the number of stored papers is small; But in low-resolution mode, the storage space is much larger.
3. Focus and zoom
Focusing refers to accurately projecting the image refracted by the lens onto the CCD photosensitive surface to form a clear image. Ordinary middle and low-grade digital cameras adopt autofocus mode and automatically adjust the focal length. High-end professional cameras retain manual focusing mode, but autofocus is enough for non-professional users.
The autofocus modes of digital cameras are generally divided into active and passive modes. The so-called active mode means that the camera actively emits infrared light invisible to the naked eye to directly illuminate the object to determine the distance, but
Focus. This method has fast focusing speed, but it is easy to produce errors. Passive focusing is automatically adjusted according to the light intensity of the image, with small error but long focusing time.
In order to shoot distant scenes or details, digital cameras have zoom function. There are optical zoom and digital zoom. The so-called optical zoom is to change the focal length of a camera lens by adjusting its optical system. The longer the focal length, the greater the projection of the object on the CCD. Digital cameras are all represented by magnification, such as 3X, 6X, 12X, etc. count
Zoom is to use the camera's own processor to enlarge the photo data through interpolation. However, this method uses mathematical methods to obtain the magnification effect, and actually does not change the resolution of the photo, so it is impossible to improve the detail clarity of the photo through digital zoom. If you really want to enlarge, it is better to transfer the photo data to a computer and use special image processing software for processing. Therefore, the optical zoom system is actually useful for digital cameras. Of course, digital cameras with optical zoom are more expensive than those without optical zoom.
In addition to the normal shooting mode, many digital cameras provide a retake mode or a close-up mode, which is mainly used to shoot close-up objects and can also be used to retake articles. In normal mode, the camera can shoot objects from 0.5 meters to infinity. In close mode, you can shoot objects 0.2 to 0.5 meters, but at this time, because of the close distance, you need to take pictures through the LCD screen that comes with the camera. It is convenient to take a digital camera when you go out to check the information, which saves the trouble of copying and directly remake the information.
Step 4 output
The photos taken by the digital camera will eventually be stored in the computer and directly transmitted to the computer through the USB port, which is very fast. In addition, there are infrared transmission, memory card display, card reader and so on. In addition, many digital cameras are equipped with video output mode, which can output video signals in PAL/NTSC format, and it is very convenient to display images with TV sets.
Step 5 show up
Most mid-range commercial and home digital cameras are simple and light in appearance, imitating the shape of ordinary fool cameras. Some of them have professional camera styles.
6. Storage format
In order to store as many photos as possible, the photo data taken by digital cameras are basically stored in JPEG mode, and the compression ratio can be selected, generally, 1/4, 1/8,116. Some digital cameras can be saved in TIFF format to ensure the quality of photos, but the number of photos saved each time is much less. In addition, some digital cameras also use their own image formats. In addition to JPEG format, Kodak's DC260 can also use its own image storage format Flash PIX.
7. Power supply
Because LCD is a big power consumer, you can only take twenty or thirty pictures with ordinary batteries on. Therefore, most of G 1 1 batteries or lithium batteries are charged with Ni-MH, which has large capacity, fast charging and more convenient use.
8. Liquid crystal display
LCD refers to a color LCD screen used to preview photos on a digital camera. LCD is not only used for preview, but also for camera mode and information display, which is convenient for operation. Because LCD is a big power consumer, in order to save electricity, some digital cameras can turn off the LCD display and view it directly with TTL. In addition, Sanyo's digital camera adds the design of light collecting plate to the LCD, which can be turned on when the ambient light intensity is high, and uses sunlight to provide backlight for the LCD, saving the power consumption of the camera.
9. Others
Different brands and models of digital cameras have their own characteristics. For example, the flash can have a variety of flash modes to choose from, and a red-eye flash mode set to prevent the red-eye effect when shooting portraits. In addition to local flash, some digital cameras can also be connected with standard flash. Some digital cameras can also attach 4 seconds of voice commentary information to each photo. There is also a fast continuous shooting, which can shoot continuously for 3 seconds at the speed of 4 frames per second, which is very useful for shooting the movements of moving objects. Other functions such as lens protection function and white balance adjustment mode will not be described in detail.
Third, shooting skills
Regarding shooting skills, different shooting methods are required. The following is the most common outdoor shooting.
1. Basic essentials of digital camera operation: stability, accuracy and firmness.
Steady means that you can't shake your hands when shooting, otherwise the picture will be blurred; Accurate, that is, accurately find the main part of the subject, master the layout of the picture, and make the whole picture full of beauty; The difficulty is to seize the opportunity and make up your mind to press the shutter, because some wonderful shots are often fleeting.
2. The shooting distance is far or near.
If you don't choose the distance of the picture well, and the distant object is unclear because there are few pixels distributed on it, then try to get close to the object you are shooting. For example, when shooting people, you can open the LCD screen to view the scene, and then try to fill the whole screen with characters. Don't shoot until you can clearly see the whites of the characters' eyes.
Avoid extreme temperatures
Too high or too low a temperature will be bad for your camera and battery. Never expose your camera to the sun for several hours. If you must be exposed to the sun, you can cover your camera with a light-colored towel or reflective material. If you put the camera on a car, you must pay attention to the fact that the direction of sunlight will change with time, so put the camera away from the sun. When it is very cold, it is best to put the camera in a big sealed plastic bag and then take it out. The temperature in the bag will gradually drop, so as to avoid frosting inside the camera because the temperature drops too fast. When your camera is as cold as the air outside, you can take it out and shoot it.
4. Problems in shooting along the light
Usually the best shooting point is when the sun is behind you, so the object you want to shoot will have excellent light. But at the same time, the problem is that the content on the LCD screen of the camera will be difficult to see clearly in such strong light, so you'd better buy a camera with an optical viewfinder, otherwise it will be difficult for you to take a good image in this case. On the other hand, if you often use the optical viewfinder instead of the LCD screen, you can also save a lot of power.
5. Use a flash when backlighting
When shooting during the day, the flash is usually used in the shadow. When you shoot in backlight (the light source is behind the object, such as sunset), the result is usually that the outline of the object is black, but the background is very bright. The solution to this problem is to use a fully charged flash, which can illuminate people's faces and effectively reduce the brightness of the background.
Four. term
1. image storage format
Because the image file shot by digital camera is very large, but the storage capacity is limited, the image is usually compressed and then stored. The most common image storage formats are jpeg and tiff files. After jpeg is highly compressed, you can change the file to its original size 1/4, 1/8 or116, which can save a lot of storage space, but also make the original image data lost. Many cameras will provide specific compression ratios for users to choose.
Tiff files are almost uncompressed, so images will be more complete than jpeg. However, the higher the image resolution, the smaller the compression and the more memory space it takes up, so it is necessary to take into account the quality requirements of the image and the capacity of the memory card when taking pictures. The amount of information is reduced, so the compression ratio can be high and the image quality will decrease accordingly.
2.gt lens
Gt lens refers to the unique design of Minolta's multi-piece and multi-group lens combination. The lens is made of high-grade low-dispersion optical glass, including several die-casting aspheric lenses and so on. In other words, Minolta's G-series high-end professional traditional camera (silver salt camera) uses af lens. Minolta applies the technology of producing G-series lens to the design and production of digital cameras, and the product produced is called gt lens.
3. Wide-angle lens
That is, wide angle, also known as short lens. Because the focal length of the wide-angle lens is very short, the scene projected on the basement membrane becomes smaller. Expanding the shooting angle of the lens can not only shoot more scenes, but also shoot wide-angle images in a narrow environment.
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