What should I pay attention to when buying a digital camera?

The main parameters of digital camera are photosensitive element type, pixel size, sensor size, lens type, optical zoom size, LCD screen size, memory card and battery.

CCD is the mainstream imaging device at present, which is mainly divided into:

(1)R-G-B primary CCD: This is the most widely used CCD in digital cameras.

(2)C-Y-G-M complementary color CCD: Some Nikon digital cameras used this complementary color CCD earlier.

(3)R-G-B-E four-color CCD: This is the latest CCD released by Sony, which has one more E (Emerald) color than RGB primary CCD.

(4) Super CCD: It is a patented technology of Fuji Company in Japan. Its Chinese name is Super CCD, which evolved from CCD and has now developed to the fourth generation.

There are many brands of lenses used in digital cameras. Knowing these lens brands is helpful for understanding and buying digital cameras.

Canon lens: Canon is a traditional optical manufacturer. This company's EF series lenses in the field of traditional cameras, especially the red circle lens representing aristocratic descent, have always been the dream of many photographers. Therefore, with years of accumulated experience in the field of traditional lens manufacturing, Canon's digital camera lenses are also of first-class quality. Canon lens has sharp imaging and true color reproduction, which effectively ensures the final imaging quality. At the same time, it also designs and provides lenses for some digital camera manufacturers, such as Casio.

Nikon Nicol lens: Nikon is a world-famous lens manufacturer with the same reputation as Canon, and its Nikkor series lenses are loved by photographers for their excellent imaging quality. Nikon's digital cameras all use Nicol series lenses, especially some high-end models, and also use expensive ED (ultra-low dispersion) lenses to obtain perfect images. Although these high-end models are expensive, many photographers don't choose them because their lenses are excellent, not Nikon's digital cameras.

Minolta GT lens: Minolta is also a well-known optical equipment manufacturer. One of the highlights of its digital camera is the GT lens-the letter "GT" indicates that it is an advanced lens specially used for digital cameras, which means that this lens is an extraordinary high-quality lens made by concentrating Minolta's unique key image processing technology (GT=G Lens Technology), which keeps chromatic aberration and distorted astigmatism to a minimum. Most of Minolta's DiMAGE series digital cameras use GT lenses.

Olympus: The fully automatic cameras produced by Olympus have a large market share in China, and its digital camera brand CAMEDIA is also deeply rooted in people's hearts. CAMEDIA series cameras all use the lenses designed and produced by Olympus, and some use the lenses with the maximum aperture of F 1.8, which is very rare in digital cameras. Olympus also gave this kind of lens a nice name-super bright.

Fuji's Fuji Dragon Lens: In addition to producing and selling films all over the world, Fuji is also a traditional camera manufacturer, and its lens brand is Fuji Dragon. After entering the digital age, Fuji is making every effort to promote the popularization of digital cameras. In order to ensure the excellent imaging quality, Fuji has made great efforts in the lens, and used super EBC coating on the lens, which has played a great role in improving the performance of the lens, which is enough to show Fuji's good intentions.

Pentax lens: Pentax's fame doesn't seem as loud as the brand mentioned above. Actually, it is not. Pentax is not only highly accomplished in the field of 135mm professional SLR cameras, but also in the field of medium-sized professional cameras. It is also for this reason that he doesn't have many opportunities to meet ordinary consumers. Pentax doesn't have many digital cameras, but each camera uses excellent Pentax lenses. In addition, Pentax also designs and supplies lenses for other manufacturers, such as Casio.

Carl. Zeiss lens: Carl? Zeiss lens is a brand from Germany and one of the few non-Japanese manufacturers at present. Carl. Zeiss is a manufacturer of optical instruments with a long history, and its lens has always been synonymous with "nobility" in the field of traditional cameras. Many color lovers have Carl? Zeiss is proud of the camera. Sony has used Carl in some of its digital cameras. Zeiss lens, and use it as a selling point. It should be noted that Sony generally uses Carl? Zeiss lens, while ordinary Sony lens is used for low-end products.

Leica lens: Leica is also a German optical instrument manufacturer with a long history. Its products are not inferior to the above brands in the world, and they can also be called "the best". In the field of digital cameras, Leica's most outstanding achievement is to design and produce lenses for Panasonic LUMIX series digital cameras and achieve success. At the same time, Leica's only digital camera Digitlux 1 also uses Leica lens.

Schneider lens: As one of the three famous lens manufacturing companies in Germany, it has a history of more than 100 years. Thanks to Carl? Because the aura of Zeiss and Leica is too dazzling, Schneider has also become unknown in the eyes of laymen. A large number of excellent brands have appeared in German traditional optical industry in the past century, but most of them were announced under the monopoly of Zeiss and Leica. Schneider is still alive with first-class design. In the early stage of development, Schneider paid attention to tolerance and strong internal force. In the field of traditional cameras, he is famous for making large format landline and enlarger lens. The lens he produces can be called the king of mirrors in the landline, and the quality of the lens he produces is not lost to other famous European brands.

In addition, I will give you detailed precautions for purchasing DC, so please wait patiently.

How to choose a digital camera

Digital camera has entered the field of mass consumption. Many friends want to own a digital camera, but they don't know how to choose. As a digital product with high technical integration, there will be a problem of how to choose it in the purchase process. Now everyone pays great attention to the number of pixels of CCD when buying digital cameras. In addition to resolution, other performance indicators of digital cameras are more worthy of consumers' attention. I will tell you how to choose the "best digital camera" with real price and practical function from different angles.

First, understand the camera.

1. pixels and resolution pixels are the most HyPic units of digital images, and each pixel is a small point. When pixels of different colors are gathered together, it becomes 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 can produce higher resolution under the CCD photosensitive unit with the same photosensitive point through special technology. What is the relationship between pixels and resolution? How to interpret these two figures when purchasing?

★ The higher the picture resolution, the more pixels are needed. For example, a picture with a resolution of 640×480 needs about 3 10000 pixels, and a picture with a resolution of 2084× 1536 needs at most 3 14000 pixels.

★ The resolution can have multiple values. The more resolution the camera provides, the more flexibility you have in taking and saving 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.

Total number of pixels refers to the total number of pixels contained in 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 the lens and shutter lens directly affects the quality of the camera. Under normal circumstances, manufacturers with deep background in traditional cameras will have better lenses in their digital cameras.

★ Focal length Due to the special lens specifications of digital cameras, it is impossible to predict the range of scenes that can be shot from this data. Most manufacturers will increase the focal length of 35mm traditional cameras after the lens focal length parameters. If it is a souvenir or a photo of life, you only need to buy the fixed-focus lens model. If there are diversified needs, a camera with three times or more optical zoom capability will be more suitable. Focal length, also called focal length, usually refers to the distance from the center point on the lens axis to when the image can be clearly imaged. In a camera, it refers to the focal length of the whole lens group in mm (millimeter). The longer the focal length, the narrower the angle of the visual range of the lens, but it has the effect of magnification and proximity, just like the lens of a telescope; The shorter the focal length, the larger the shooting range and the smaller the relative object, which is suitable for shooting large scenes at close range, which is what we often call a wide-angle lens. For digital cameras, the longer the focal length, the longer the depth of the lens group. In addition, data such as f=5.5mm or 5.5mm can be found from the camera lens. However, because the focal length of the lens of a digital camera is generally much shorter than that of an ordinary 35mm camera, manufacturers often indicate something similar in the manual: a 36mm lens is equivalent to a 35 mm camera for users to compare.

★ Aperture range The larger the aperture, the more you 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 there is a wider shutter range, it can better meet all kinds of strict 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. 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, various digital cameras have different abilities, and some can even close to 0. 1 cm for close-up.

4. Other functions, such as red-eye flashing, 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. The photosensitive element of a digital camera is fixed, so it is necessary to reflect the change of light source with the help of white balance correction ability. 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 camera's automatic exposure function is based on the light entering amount of medium gray reflected light, if there is too much white (reflected light) in the shooting picture, the light entering amount will be higher than the photometric standard value, thus misleading the camera to think that the light is very strong and the aperture is reduced, resulting in underexposure of the photo and the white part becoming 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.

Many consumers, because they don't understand digital cameras, unilaterally think that pixels are high. Not exactly. When choosing a digital camera, we should consider its digital and optical characteristics.

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, it has become an important standard for digital camera classification. 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 screens and built-in flashlights, so the battery consumption is higher 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. 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 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. The size of CCD, like TV, 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×5.3mm) 1/2 inches (4.8 mm× 6.4 mm)1/0.8 inches (5.19 mm× 6.9/.

Second, the four basic principles of purchasing machines

● 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, the dominant 3-megapixel and 5-megapixel models in 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 consumers who pursue fashion avant-garde, the close combination of shape design and prominent function is the first choice 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. 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 it. A regular digital camera sales counter will ensure that your camera is "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 camera

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

It is very important to determine the purpose and purpose of buying a camera. Only by knowing your own needs can you choose to buy the machine you really need through mergers and acquisitions. 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 are needed to buy a machine. If you just look at it from 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 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. DC is still a luxury, so everyone must do his best. There is no point in comparing with others, just enough.

Step 3: Collect information through various channels.

Early data collection is very important, which can give us a certain understanding of the machine 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.

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. The real machine may look different from 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 to buy the machine, we should choose "auspicious day" to buy DC back. When I say "auspicious day", I actually want to seize the opportunity myself. 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.

You must read when you buy a camera.

When buying a camera, you need to check it carefully to avoid buying defective products or being cheated by JS (profiteer). Here we give a detailed inspection step, as long as you follow the following instructions, there will be no problem:

1. Never pay JS first, and then pay after inspection;

2. See if the packaging is old. If so, it may be replaced by others, or a product that JS has stored for a long time;

3. After unpacking, check whether the accessories in the box have been used or obviously disassembled; Pay special attention to whether there are scratches on the battery pins;

4. Check the appearance of the machine. Look for scratches on the fuselage, including lens, LCD, EVF and shell.

5. Try to shoot, and zoom to see if you can shoot clearly. If you are not familiar with the machine you are going to buy, you can shoot it with an automatic file when you try it out. In addition, the flash has to be tried;

6. Then take a closer look at the LCD and EVF. You can block the lens a little with your hand, so that you can see a solid color image, or face the black and white paper.

7.CCD is the key component of DC. If there are bad spots on it, it will affect shooting. Because it is difficult to see the bad points of CCD directly on DC, it is necessary to import the picture into PC and watch it again. If there is no computer in the business, it is recommended to talk with the business about a certain replacement cycle, and then go home and feel at ease to test;

How to test bad points

Before we discuss how to test bad points, we need to explain what bad points are. Simply put, it is a point on the CCD that will never be sensitive, or this point will always be on. Usually always at the top, rarely not. So why is there a bad point? This is related to the manufacture of CCD. Although the technology is very developed now, it still can't guarantee the high output of CCD. Just like LCD, it may be defective. So we need to test the machine after we buy it.

The test of bad points is actually relatively simple. We can test it in two ways: one is to look at the original picture with our eyes. In fact, this method is more intuitive, but be careful, otherwise it is easy to miss points. The second is to test with software. The most popular bad point testing software is DEADPIXEL. Usually, if there is a computer in the place where DC is sold, this software can be bought there.

Before the test, we should take some all-black photos first. Ordinary photos can't be tested. This is very important. For the machine with lens cover, we only need to cover the lens cover to shoot. If there is no lens cover, such as Casio, then we can put a thick piece of paper on the flat panel, put down the DC lens and buckle the lens on the paper to shoot. It should be noted that the light must not enter the lens, and at the same time, don't use too much force, which will easily damage the machine.

The shooting parameters can be set to the maximum aperture and ISO 100. As for the shutter, we need to choose 1/60 and the slowest shutter. That is, take a photo with different shutter speeds.

After shooting, we can import the photos into the computer and open DEADPIXEL for testing. After opening this software, we can see the interface as shown below. We click the "Browse" button and select the photos that need to be tested. Then we press the test button and the results will appear. If the photo of 1/60 is more noisy than 10, try to change it, otherwise it may affect the shooting.

Check that all accessories are there. Usually there is a list in the box, which explains in detail how many accessories are included, and we can compare them.

Selection of accessories

Of course, after buying DC, we need to buy some accessories so that we can shoot better. Accessories are actually important. If we don't buy it well, it may affect our normal shooting. Usually we may need to buy memory cards, batteries and chargers, UV and adapter rings, camera bags, tripods and so on. Some people like to buy all digital cameras at once. I think if you buy these at the place where DC is sold, the price will definitely not be cheap. Except for the memory card, everything else should be bought in a special photographic equipment store, which is not only reliable in quality, but also cheaper in price. Let's talk about the places that need to be paid attention to when buying these accessories.

Memory card: When purchasing a memory card, you should consider your daily shooting amount and combine your DC to determine the capacity of the card you need to purchase. Secondly, we need to consider the brand of the card. At present, there are many card brands on the market, and the brand of the card determines the quality of the card in a certain sense. For example, kingstone)CF card and Toshiba SD card are not very fast, but the quality is absolutely first-class and the compatibility is good. Third, consider the speed of the card. There are two kinds of cards sold now: normal speed and high speed. If you need to take photos in RAW or even TIFF format, try to buy a high-speed card.

Batteries and chargers: There are generally two kinds of batteries used in DC, one is rechargeable lithium battery, and the other is AA (No.5) nickel-metal hydride battery. For rechargeable lithium batteries, my suggestion is that you buy them in regular stores. On the one hand, there is quality assurance, on the other hand, there is a high probability of buying fake goods. For Ni-MH battery, GP mobile Altman battery is not very expensive at present, and the quality is first-class, of course, domestic products are not bad. We try to buy something with a larger capacity, such as 2000mAh. For chargers, many digital cameras are given away at random now, so I won't introduce them in detail here.

UV and adapter ring: the main function of UV for digital cameras is to protect the lens. Do you need to buy this? I think the first thing depends on what machine you use. If the machine is small, it is better not to consider it. Because usually UV can only be installed on the machine through the adapter ring or drum, the volume of the camera is increased. If the machine itself is relatively large, such as Canon EOS350D, this is more suitable. There are many brands of UV, so it is recommended to consider multilayer coating. When buying UV, you should also consider the caliber of UV. If you are not familiar with this, you can take your camera to buy it. In addition, after installing UV, the original lens cover may not be covered. We need another one.

Photographic bag: Be sure to consider the location of accessories and bring the machine to buy it. Only in this way can we buy the right one. The bigger the camera bag, the better, but the best fit. In addition, pay attention to the material of the bag and try to buy a waterproof bag.

Tripod: Pay attention to its stability when choosing a tripod, and don't buy a rickety one. In addition, pay attention to the weight. If you are strong and just need exercise, then this may not be a problem. Weifeng brand is the most popular brand in the market. This brand of tripod is cheaper and things are ok. Admiralty, an imported brand from Japan, has a long history, and many top photographers in the world have chosen this brand. The price is not very expensive.