How to choose a digital camera

Lead: When buying a camera, you need to check it carefully to avoid buying defective products or being cheated by JS (profiteer). Many users who buy digital cameras for the first time will take pixels as the primary consideration. In their view, pixels are the basis for judging the quality of digital cameras. It seems that a high-pixel digital camera is bound to get high-quality shooting results. In fact, the relationship between pixels and image quality is far from simple.

How to choose a digital camera method 1;

First of all, know about digital cameras.

1. Digital camera pixels and resolution pixels are the most basic units of digital images, each pixel is a small point, and points (pixels) of different colors get together to become a moving photo. Digital cameras often use pixels as the basis for classification, but many people think that the number of pixels is the number of photosensitive points on the CCD photosensitive unit. In fact, this statement is not entirely correct. At present, many manufacturers adopt special technology. Digital photos with higher resolution can be made under the CCD photosensitive unit of the same photosensitive point, such as SuperCCD of Fuji digital camera and HyPic technology of Epson digital camera. What is the relationship between pixels and resolution? How to interpret these two figures when purchasing?

★ The higher the resolution of the picture, the more pixels are needed, such as a resolution of 640? 480 pictures, about 3/kloc-0.0 million pixels, 2084? The picture of 1536 needs up to 31400,000 pixels.

★ The resolution can have multiple values. The higher the resolution provided by a digital camera, the more flexible it is to take and save photos.

★ The resolution of the picture is related to the imaging size and magnification at the time of output. The higher the resolution, the larger the imaging size and the higher the magnification.

The total number of pixels in a digital camera refers to the total number of pixels contained in a CCD. However, due to the lack of light at the edge of CCD, some of them do not need to be photographed. Subtracting this part of pixels from the total number of pixels is the effective number of pixels. Therefore, when reading the product manual, remember to pay attention to the effective number of pixels that can be used in actual shooting, not the total number of pixels.

2. The quality of digital camera lens and shutter lens directly affects the quality of the camera. Under normal circumstances, manufacturers with deep traditional camera background will also have better lenses for their digital cameras.

★ The larger the aperture range of a digital camera, the more it can adapt to the lack of light. If there are more than two aperture values, the application flexibility of the camera will be greater. Aperture is one of the important mechanisms that affect exposure. It usually refers to the control device composed of about 5 to 9 pieces of metal in the lens group, which can form circles with different sizes to control the amount of light entering the lens. The larger the aperture, the more light per unit time. The size of the aperture is expressed by numbers. The larger the number, the smaller the aperture, that is, the less light enters. All the marks on the lens refer to the maximum aperture of the lens, that is, the value in the fully open state, such as 1: 3.2, but on the zoom lens, you will see the marks of 9.2-28mm 1: 2.8-F3.9, indicating that the maximum aperture is F2.8 when the focal length is 9.2mm and the maximum aperture when the focal length is 28mm.

★ Shutter The shutter of a digital camera can support 2 ~11000 seconds, which can meet the general requirements. Of course, if you have a wider shutter range, you can better meet all kinds of harsh shooting conditions, such as shooting high-speed moving objects or starry nights. The shutter is used to adjust the exposure time of the camera. The unit is seconds, expressed in reciprocal. For example, 30 and 250 represent 1/30 seconds and 1/250 seconds respectively, so the smaller the number, the slower the shutter speed. The faster the shutter speed, the easier it is to capture high-speed moving images. Generally, it is not easy to blur the image due to jitter when shooting, but high speed may lead to insufficient light input. Usually, when the light is strong, you must use a high-speed shutter or increase the aperture. When the light is insufficient, a slow shutter is more suitable, but a tripod may be needed for assistance.

3. Digital camera macro shooting macro is to zoom in and out the subject to be shot. The point is to shoot tiny objects to the size you want. In macro mode, all kinds of digital cameras have different abilities, and some of them can even be close to 0. 1 cm for close-up shooting.

4. Other functions of the digital camera, such as eliminating red-eye flash, white balance and exposure compensation, will have greater flexibility for shooting in various environments.

★ Automatic white balance correction The photosensitive part of a digital camera is equivalent to the negative of a traditional camera, and the photosensitive element of the digital camera is fixed, so it is necessary to use the white balance correction ability to reflect the change of the light source. It is mainly designed for photosensitivity in different environments. Different light sources will produce different degrees of chromatic aberration, which may make the color blue and yellow, and the white balance correction can be corrected.

★ Exposure compensation Because the automatic exposure function of digital camera is based on the amount of light reflected by medium gray, if there is too much white in the shooting picture (too much reflected light), the amount of light will be higher than the photometric standard value, so the camera will be misled into thinking that the light is very strong and the aperture will be reduced, resulting in underexposure of the photo and the white part will become not white enough. Exposure compensation is aimed at this situation. Only when the exposure is increased by 1 or 2 frames can a bright and correct image be obtained. On the other hand, in most cases of black, it is necessary to reduce the exposure of 1 or 2 squares.

1, digital camera lens. A well-designed high-end camera lens consists of multiple groups of lenses, including aspherical lenses, which can significantly reduce color shift and minimize graphic distortion and distortion. Expensive fluorite or glass is used as a lens. In order to reduce weight and cost, the lenses of household and semi-professional cameras are made of resin.

2. Image value of CCD of digital camera. CCD is the heart of digital camera, and it is also one of the main factors that affect the manufacturing cost of digital camera. Therefore, the classification of digital cameras has become an important standard. At present, entry-level products are all 3-5 million pixels, and commercial and semi-professional users prefer products with more than 5-/kloc-0.0 million pixels.

3. Zoom of digital camera. Optical zoom is a real zoom, which will not affect the imaging quality of photos; Digital zoom is electronic zoom, which is a local enlargement at the expense of photo clarity.

4. Battery and power consumption of digital camera. Digital cameras have LCD display and built-in flash, so the battery consumption is larger than that of traditional cameras. It's cheap to use the No.5 battery, and you can buy it anytime and anywhere, but it won't take long for the battery to die. Therefore, it is best to choose the model equipped with rechargeable lithium battery. At present, mainstream digital products have been designed as lithium batteries, and complete charging equipment is provided as accessories.

5. Additional functions of digital camera. The more functions, the more fun and uses it means to use a digital camera. For example, many digital cameras have video output function, which can be connected to TV to browse photos; Some can set their own startup screen and shutter sound like mobile phones; Some can have short-term digital video recording function. The driver installation of digital camera should be very simple, and it should be able to download pictures quickly and preview them. For example, the software function attached to Canon digital camera is perfect, which can classify and manage pictures, and the settings when printing are more diverse, and pictures can also be simply modified.

Image sensor is the decisive factor of digital camera performance. Generally speaking, the pixel value of the image sensor should be greater than the maximum pixel value of the real shot image. In order to make up for the pixel shortage of image sensors, some manufacturers use software interpolation to improve the pixel value of images. In fact, this interpolation method can be realized in almost all image processing software, so it is of little practical significance. The purchase must be based on the hardware pixel value of the image sensor, not the maximum pixel value of the output image.

Digital cameras record photo information in a semiconductor element called CCD (Charge Coupled Device), instead of the film of a silver salt camera. CCD size, like TV set, refers to the diagonal length, expressed in inches, such as? 1.27 inch (note)? . The larger the CCD, the more pixels and the higher the sensitivity. Therefore, with the same number of pixels, the larger the CCD, the better the image quality. ? CCD size 1/2.7 inches (4.0mm? 5.3 mm) 1/2 inches (4.8 mm? 6.4 mm)11.8 inch (5. 19 mm? 6.9 1 mm) 2/3 inch (6.6 mm? 8.8mm) Note: 1 inch is equal to 2.54cm, and the CCD of digital camera adopts the same representation as that of TV picture tube.

Second, the four principles of digital camera purchase

● For ordinary home users, if they are limited to family entertainment, they pay great attention to practicality. Powerful functions and high cost performance brought by durability are the first choice factors. At present, more than 5 million digital cameras that dominate the market can meet the imaging requirements. A variety of shooting modes, a wide range of ISO values and high-speed and accurate focusing are necessary functional characteristics, and a metal shell that ensures durability is also an essential consideration.

● For those consumers who pursue fashion avant-garde, the close combination of digital camera shape design and highlight function is the preferred standard. Small shape, bright colors and comfortable hand feel are essential, and some highlight functions, such as macro shooting, are icing on the cake for this kind of products.

● If you are a professional user, the most important thing is the ultimate pursuit of imaging quality by digital cameras. Manual operation function is necessary. Replaceable lens, CMOS image sensor with more than 6 million pixels and various image recording modes are the guarantee of high image quality. If we have an explosion of less than ten thousand yuan, more professional photographers will flock to us.

The last thing to consider is where to buy a digital camera. Will the regular digital camera sales counter guarantee your camera? Born? . Brand effect should be considered when purchasing, because it is the main guarantee for the overall quality and after-sales service of digital cameras.

Third, the preparation steps for buying a digital camera

Step 1: Make clear the purpose and purpose of buying a digital camera.

It is very important to determine the purpose and purpose of buying digital cameras. Only by knowing your own needs can you choose to buy the digital camera you really need. Otherwise, you may spend a lot of money on the camera, and it turns out that the functions can't meet your own requirements, or there are too many functions to use at all. We can think about what we buy digital cameras for. For example, some friends buy digital cameras to travel; Some friends want to learn photography; Some friends want to take macro photos; Of course, some people want to take close-ups or take pictures of their newborn children as a souvenir. In short, we must clearly understand consumption.

The output of photos also needs to be considered in advance, whether it is necessary to develop large photos or just watch them on the screen. Through this consideration, we can decide how many pixels we need to buy a digital camera. If you just look at it on the screen, then a 3 megapixel machine is enough. If we want to print, and print to more than 10 inch, then we need to buy a camera with pixels as high as possible.

Step 2: Decide the psychological price.

After deciding the purpose and use of buying a digital camera, you should decide an affordable psychological price according to your own economic ability, such as 3000 ~ 4000 yuan or 6000 ~ 7000 yuan. This can help us save a lot of time and be more purposeful when choosing. Digital cameras are still luxury goods, so we must do what we can. There is no point in comparing with others, just enough.

Step 3: Collect information through various channels.

It is very important to collect information in advance, so as to have a certain understanding of the digital camera to be purchased. There are many ways to collect product information. First of all, many manufacturers will have certain publicity pictorial when they launch digital cameras. We can go to the vendor and have a look. Secondly, media advertising is also a very important way. There are many advertisements for digital cameras in IT newspapers now, so we should pay attention to them. Thirdly, many digital magazines or some newspapers now have a certain space to introduce or evaluate digital cameras, and we can also buy some to read.

If possible, you can download the manual of the corresponding camera and have a look. This is very good for buying a machine: on the one hand, it can make you more familiar with the machine, on the other hand, it can make you ready for basic operation when buying a machine. I like reading instructions myself.

Technical data can let us know the appearance, function and other information of digital cameras. We should look at the actual photos. In this way, you can know the characteristics of DC you are concerned about, such as color, image quality and so on. We can go to the digital photography website to learn about this.

Step 4: roughly determine the model of the digital camera.

The collection of product information is very important, which allows us to fully understand the characteristics of digital cameras. But just looking at these materials, we can only have a perceptual understanding. Only by actually looking at the machine or even trying it out can we have a rational understanding of the machine. This requires us to go to the mall. We can look at the samples in the window or counter. A real digital camera may look different from the one in the photo, or it may look better. We can also watch others buy machines and listen to what others say. Of course, we can also let the merchants take out the machine, actually touch it and operate it. Depending on the machine, you should also ask the price. When asking about the price, you should pay attention to the fact that the quotation of the merchant usually leaves room for counter-offer. Also, ask them if the price they quoted is licensed or parallel.

Step 5: Choose the right time to buy.

After deciding which digital camera to buy, which one should I choose? Jiri? Bought back a digital camera. Did I say that? Jiri? In fact, we should seize the opportunity ourselves. The price of digital products changes rapidly, so it is very important to judge the market. However, obviously, you should avoid buying before the festival as much as possible. There must be a lot of people buying machines before the holiday, and the price will not be cheap.