How to check the goods when buying a card machine, and what aspects should I pay attention to?

many consumers, because they don't know about digital cameras, unilaterally think that high pixels are good. Not really. When purchasing a digital camera, we should give consideration to its digital characteristics and optical characteristics.

1. The lens of a digital camera. A well-designed high-end camera lens is composed of multiple groups of lenses and contains aspherical lenses, which can significantly reduce color shift and minimize graphic distortion and distortion. The expensive fluorite or glass is used as the lens. In order to reduce the 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 classifying digital cameras. At present, the entry-level products are 3-5 million pixels, while commercial and semi-professional users prefer products with more than 5-1 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. Using the No.5 battery is cheap and can be bought anytime and anywhere, but it won't take long for the battery to die. Therefore, it is best to choose a model equipped with rechargeable lithium batteries. 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 there are, the more fun and versatile it means to use digital cameras. For example, many digital cameras have video output function, which can be connected to TV to browse photos; Some can set their own startup pictures and shutter sounds like mobile phones; Some can have short-term digital video recording function. The installation of the driver of digital camera should be very simple, and it should be able to download pictures quickly and have photo previews. 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 varied, and pictures can also be simply modified.

The image sensor is the decisive factor of the camera performance. In general, the pixel value of the image sensor should be greater than the maximum pixel value of the real shot image. Some manufacturers use software interpolation to increase the pixel value of the image in order to make up for the pixel shortage of the image sensor. 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 rather than the maximum pixel value of the output image.

digital cameras record photographic information in a semiconductor element called CCD (Charge Coupled Device), not on the film of a silver salt camera. The CCD size, like the TV set, refers to the diagonal length, expressed in inches, such as "1.27 inches (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 inch (4.mm×5.3mm)1/2 inch (4.8mm×6.4mm)1/1.8 inch (5.19mm×6.91mm)2/3 inch (6.6mm×8.8mm) Note: 1 inch is equal to 2.54cm, and the CCD of digital camera is adopted.

Second, the four basic principles of purchasing a machine

● For ordinary home users, if they are limited to family entertainment and pay great attention to practicality, powerful functions and high cost performance brought by durability are the first choice factors. At present, the 3-megapixel and 5-megapixel models that dominate the market can meet the imaging requirements. Multiple shooting modes, wide ISO value setting range and high-speed and accurate focusing are necessary functional features, and the metal casing that ensures durability is also an essential consideration.

● For those consumers who pursue fashion avant-garde, the close combination of shape design and highlight 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 the icing on the cake for this kind of products.

● if you are a professional-level 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 explosive price of less than 1, yuan, more professional photographers will flock to it.

● The last thing to consider is where to buy. 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 preparatory steps for buying a camera

Step 1: Define the purpose and purpose of buying a camera

It is very important to determine the purpose and purpose of buying a camera. Only by knowing our own needs can we choose to buy the machine we really need through mergers and acquisitions. Otherwise, it is possible to 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 bought a digital camera for. For example, some friends buy digital cameras to travel; Some friends hope to learn photography; Some friends want to take macro photos; Of course, some people want to take close-up photos of people or take pictures of their newborn children as souvenirs. In short, we must clearly consume.

The issue of photo output also needs to be considered in advance, and whether you need 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 machine. If we just look at it on the screen, then a machine with 3 million pixels is enough. If we want to print, and print to more than 1 inches, then we need to buy a camera with as high a pixel as possible.

Step 2: Decide the psychological price

After deciding the purpose and purpose of buying a camera, we should decide an affordable psychological price according to our economic ability, such as 3 ~ 4 yuan or 6 ~ 7 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 what they can. It is meaningless to compare with others, just enough.

Step 3: Collect data through various channels

It is very important to collect data in the early stage, so that we can have 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 pictorials when they launch digital cameras. We can go to the vendors to have a look. Secondly, media advertising is also a very important way. There are many digital camera advertisements in IT newspapers today, so we should pay attention to them. Thirdly, now many digital magazines or some newspapers will 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 machines: on the one hand, it can make you more familiar with the machines, on the other hand, it can make you prepared for the basic operation when you buy them. I like reading instructions very much myself.

technical data can help us understand the appearance, functions and other information of digital cameras. And 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

it is very important to collect product data, which can let us 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 prototype in the window or counter. The real machine may look different from the one in the photo, or it may look better. We can also watch other people 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 about 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 whether the price they quoted is licensed or parallel.

Step 5: Choose the right time to buy

After deciding on the machine to buy, you should choose "auspicious day" to buy DC back. When I say "auspicious day", I actually want to seize the opportunity by myself. The price of digital products changes rapidly, so it is very important to judge the market. However, it is clear that you should avoid buying before the festival as much as possible. There must be a lot of people buying machines before the festival, and the price will not be cheap.

Must-read when buying a camera

When buying a camera, we 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, but pay after the inspection;

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

3. after opening the box, 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, etc.

5. Try to shoot, and use the zoom to see if you can shoot clearly from far and near. If you are not familiar with the machine you are going to buy, you can use the AUTO file to shoot it 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 white paper and dark paper.

7.CCD is the key component of DC, and if there are bad spots on it, it will affect shooting. Because it is difficult to see the bad spots of CCD directly on DC, it is necessary to import the pictures into PC to see them again. If the merchant doesn't have a computer there, it is recommended to talk with the merchant about a certain replacement period, and then go home and test with peace of mind;

how to test a bad point

before we talk about how to test a bad point, we need to explain what a bad point is. Simply put, it is a point on the CCD that will never be sensitive, or this point will always be on. Usually it is always on the most, and it is very rare that it is not. So why are there bad spots? This is related to the manufacture of CCD. Although the technology is very developed now, it still cannot guarantee a high yield for CCD. Just like LCD, there may be defects. So we need to test the machine after we buy it.

the test of bad points is actually relatively simple. We can use two methods to test: 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 is available there.

before the test, we should first take some all-black photos. Ordinary photos can't be tested, which is very important. For a machine with a 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 a flat table, put the DC lens down and buckle the lens on the paper to shoot. It should be noted that light must not enter the lens, and at the same time, don't use too much force, which will easily damage the machine.

when shooting, we can set the parameters as the maximum aperture and ISO 1. As for the shutter, we need to choose 1/6th and the slowest shutter. That is, take one photo at different shutter speeds.

after shooting, we can import the photos into the computer and open the DEADPIXEL for testing. After opening this software, we can see the interface as shown below. We click the "Browse" button and select the photos we need to test. Then we press the TEST button and the result will appear. If 1/6 photos test more than 1 noise points, then try to change one, otherwise it may affect the shooting.

check whether all the accessories are there. usually, there is a list in the box, which explains in detail how many random accessories there are, and we can check them against it.

accessories selection

Of course, we need to buy some accessories when we buy DC, so that we can shoot better. Accessories are actually very important. If you don't buy them 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 the digital cameras at once. I think if you buy these in a place where DC is sold, it will definitely not be cheap in price. In addition to the memory card, other things 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 in different categories.

memory card: when buying a memory card, you should consider your daily shooting amount and combine your DC to determine the capacity of the card you need to buy. Secondly, we need to consider the brand of the card. At present, there are many brands of cards on the market, and the brand of cards determines the quality of cards in a 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. Thirdly, we should consider the speed of the card. There are two kinds of cards sold now: ordinary speed and high speed. If you need to take photos in RAW or even TIFF format, try to buy high speed cards.

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-hydrogen 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 fakes. For Ni-MH battery, GP Ultraman battery is not very expensive at present, and its quality is first-class, of course, domestic products are not bad. We try to buy something with a larger capacity, such as 2mAh. 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, then it is better not to consider it. Because usually UV can only be installed on the machine by adapter ring or adapter barrel, which increases the size of the camera. If the machine itself is relatively large, such as Canon EOS35D, this is more suitable. U