How to choose a digital camera

The main parameters of a digital camera include photosensitive element type, pixel size, sensor size, lens type, optical zoom size, LCD screen size, which memory card to use, which battery to use, etc.

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

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

(2) C-Y-G-M complementary color CCD: Earlier, some Nikon digital cameras used this complementary color CCD.

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

(4) Super CCD: It is a patented technology of Fujifilm Corporation of Japan. Its Chinese name is Super CCD. It evolved from CCD and has now developed to the fourth generation.

There are many brands of lenses used on digital cameras. It is helpful to understand and purchase digital cameras to understand these lens brands.

Canon lenses: Canon (CANON) is a traditional optical manufacturer. The company's EF series lenses in the traditional camera field, especially the red circle lenses that represent noble blood, have always been the favorite of many photography enthusiasts. dream. Therefore, with many years of experience in traditional lens manufacturing, the digital camera lenses produced by Canon are also of first-class quality. Canon lenses produce sharp images and true color reproduction, effectively ensuring the final image quality. At the same time, it also designs and provides lenses for some digital camera manufacturers, such as Casio.

Nikon Nikkor lenses: Nikon is a world-famous lens manufacturer as famous as Canon. Its Nikkor series lenses are loved by photography enthusiasts for their exceptionally excellent image quality. Nikon digital cameras all use Nikkor series lenses, especially some high-end models, which also use expensive ED (extra-low dispersion) lenses to get perfect images. Although these high-end models are expensive, many photography enthusiasts do not choose them over Nikon digital cameras because of their excellent lenses.

Minolta GT lens: Minolta is also a well-known optical equipment manufacturer. One of the highlights of its digital cameras is the GT lens - the two letters "GT" represent that it has passed strict judgment standards. As for the high-end lenses selected specifically for digital cameras, it means that this lens is made by condensing Minolta's unique key image processing technology (GT=G Lens Technology) that controls chromatic aberration, distortion and astigmatism to a minimum. Exceptional high-definition footage. Most of Minolta's DiMAGE series of 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 the hearts of the people. CAMEDIA series cameras all use lenses designed and produced by Olympus. Several of them use lenses with a maximum aperture of F1.8, which is very rare among digital cameras. Olympus also gave this lens a nice name - SUPER BRIGHT.

Fuji’s Fujilon lenses: In addition to producing film that is sold around the world, Fujifilm was originally a traditional camera manufacturer, and its lens brand is Fujilon. After entering the digital age, Fujifilm has made every effort to promote the popularization of digital cameras. In order to ensure excellent imaging quality, Fujifilm has worked hard on 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 Fujifilm's good intentions.

Pentax lenses: Pentax’s reputation does not seem to be as famous as the previously mentioned brands. In fact, it is not the case. Pentax not only has high attainments in the field of 135mm professional SLR cameras, but also in the field of medium-format professional cameras. Yue Zhongtian - It is for this reason that he does not have many opportunities to meet ordinary consumers. Although Pentax does not have many digital camera products, each camera uses high-quality Pentax lenses. In addition, Pentax also designs and provides lenses for other manufacturers, such as Casio.

Carl Zeiss lenses: Carl Zeiss lenses are a brand from Germany and one of the few non-Japanese manufacturers. Carl Zeiss is an optical instrument manufacturer with a long history. The lenses it produces have always been synonymous with "nobility" in the field of traditional cameras. Many color enthusiasts are proud to own Carl Zeiss lenses. Sony uses Carl Zeiss lenses on some of its digital cameras and uses them as a selling point. It should be noted that Sony generally uses Carl Zeiss lenses on its high-end digital cameras, while its mid- to low-end products use ordinary Sony lenses.

Leica lens: Leica is also an optical instrument manufacturer with a long history from Germany. The reputation of its products in the world of cameras is no less than that of the aforementioned brands, and it also has the reputation of "top quality". say. In the field of digital cameras, Leica's most outstanding achievement is the design and production of lenses for the Panasonic LUMIX series of digital cameras and its success. At the same time, Leica’s only digital camera DIGILUX 1 also uses Leica lenses.

Schneider Lens: As one of the three well-known lens manufacturing companies in Germany, it has a history of more than 100 years. Due to the dazzling aura of Carl Zeiss and Leica, Schneider Lens Germany has become unknown in the eyes of outsiders. In Germany's century-old traditional optical industry, there have been a large number of excellent brands, but most of them were announced and launched under the monopoly of Zeiss and Leica. However, Schneider is still strong with its first-class design. alive. In the early days of its development, Schneider emphasized the importance of large-scale and strong internal strength. In the field of traditional cameras, it was famous for manufacturing medium and large-format base cameras and lenses for enlargement. The lenses it produced were among the mirrors among base cameras. King, the quality of the lenses it produces is not inferior to other well-known European brands at all.

In addition, I will give you detailed precautions on purchasing DC, so be patient and read it.

How to choose a digital camera

Digital cameras have 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 a high degree of technology integration, there will be a question of how to choose during the purchase process. Nowadays, when everyone buys a digital camera, they focus on the number of pixels of the CCD. In addition to resolution, other performance indicators of digital cameras are actually more worthy of consumers' attention. I will tell you from different angles how to choose a camera that is affordable and has great functions. Practical "Best Digital Camera".

1. Understanding cameras

1. Pixels and resolution Pixels are the most basic units of digital images. Each pixel is a small dot, and dots (pixels) of different colors are gathered together. It turns into a moving photo. Digital cameras often use pixels as the basis for classification. However, 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 completely correct. Currently, it is not A few manufacturers can use special technologies to produce higher-resolution digital photos using CCD photosensitive units with the same photosensitive point, such as Fujifilm's SuperCCD and Epson's HyPic technology. What is the relationship between pixels and resolution? How should you interpret these two numbers when purchasing?

★The higher the resolution of the picture, the more pixels are required. For example, a picture with a resolution of 640×480 requires approximately 310,000 pixels, and a picture with a resolution of 2084×1536 requires up to 3.14 million pixels.

★Resolution can have multiple values. The more resolutions the camera provides, the higher the flexibility of shooting and saving pictures.

★Picture resolution is related to the image size and magnification ratio during output. The higher the resolution, the larger the image size and the higher the magnification ratio.

The total number of pixels refers to the total number of pixels contained in the CCD. However, since the edges of the CCD do not receive light, some parts of it cannot be used for shooting. 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 for actual shooting, rather than 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 a strong background in traditional cameras will have better digital camera lenses.

★Focal length Due to the special specifications of digital camera lenses, it is impossible to predict the range of scenes that can be photographed from this data. Most manufacturers will add a value equivalent to the focal length of a 35mm traditional camera after the lens focal length parameter. If it is a travel souvenir or daily life photo, you only need to buy a fixed-focus lens model. If you have diverse needs, a camera with three times or more optical zoom capabilities will be more suitable. Focal length, also called focal length, usually refers to the distance from the center point on the axis of the lens to when the image can be clearly imaged. In a camera, it refers to the focal length of the entire lens group. The unit is mm. The longer the focal length, the narrower the viewing angle of the lens, but it has the effect of magnifying and getting closer, just like the lens of a telescope; the shorter the focal length, the larger the shooting range, and the relative objects will be smaller, so it is suitable for shooting larger objects at close range. A large scene 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, you can also find data such as f=5.5mm or 5.5mm from the camera lens. However, because the focal length of the lens of a digital camera is generally longer than that of an ordinary 35mm cameras are much shorter, so many manufacturers will indicate something like: 36mm lens equivalent to 35mm camera on the manual for users to compare.

★Aperture range The larger the aperture, the better it can adapt to insufficient light. If there are more than two aperture values, the camera's application flexibility will be greater. Aperture is one of the important mechanisms that affects exposure. It usually refers to a control device composed of about 5 to 9 metal sheets in the lens assembly. It can form circles of different sizes to control the amount of light entering the lens. The larger the aperture, the more light enters per unit time. The size of the aperture is represented by a number. The larger the number, the smaller the aperture, which means less light enters. What is marked on the lens refers to the maximum aperture of the lens, which is the value in the fully open state, such as: 1:3.2, but on the zoom lens, you will see the mark 9.2-28mm1:2.8-3.9, indicating that in The maximum aperture at the focal length of 9.2mm is F2.8, while the maximum aperture at the focal length of 28mm is F3.9.

★Shutter digital camera shutter can support 2 ~ 1/1000 seconds, which can meet the general needs. Of course, if it can have a wider shutter range, it can better meet various strict shooting conditions, such as shooting at high speed Moving objects or the still night starry sky, etc. The shutter is used to adjust the exposure time of the camera. The unit is seconds and is expressed as a reciprocal. For example: 30 and 250 mean 1/30 second and 1/250 second, 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 less likely to blur the image due to shaking during shooting. However, a fast shutter speed may result in insufficient light intake. Usually, a high-speed shutter must be used when the light is strong, or the aperture must be adjusted accordingly. enlarge. When the light is insufficient, a slow shutter speed is more suitable, but a tripod may be needed.

3. Macro shooting Macro is to bring the subject to be photographed closer and enlarge it. The focus is to photograph small objects into the size you want. In terms of macro mode, various digital cameras have different capabilities. Some can even get as close as about 0.1 centimeters for close-up photography.

4. Other functions, such as red-eye flash elimination, white balance, exposure compensation and other functions, will provide greater flexibility for shooting in various environments.

★Automatic white balance correction The photosensitive part of a digital camera is equivalent to the film of a traditional camera. The photosensitive element of a digital camera is fixed, so the white balance correction capability is needed to reflect changes in the light source. It is mainly designed for different light sensitivity levels in different environments. Different light sources will produce different degrees of color deviation, which may make the color bluer or yellower. White balance correction can correct this.

★Exposure compensation: Since the camera’s automatic exposure function uses the amount of light reflected by medium gray as the comparison standard, if there is too much white (more reflected light) in the shooting screen, the amount of light will be high. Therefore, the camera is misled into thinking that the light is very strong and narrows the aperture, causing the photo to be underexposed and the white part to become not white enough. Exposure compensation is for this situation. Only by increasing the exposure by 1 or 2 stops can you have a bright and correct image. On the contrary, in most cases of black, the exposure needs to be reduced by 1 or 2 stops.

Because many consumers do not understand digital cameras, they one-sidedly believe that the one with higher pixels is better. Not really. When purchasing a digital camera, consider both its digital and optical features.

1. Digital camera lens. Well-designed high-end camera lenses are composed of multiple sets of lenses and contain aspherical lenses, which can significantly reduce color casts and minimize graphic distortion. The lenses are made of expensive fluorite or glass. In order to reduce weight and cost, the lenses of home and semi-professional cameras use lenses made of resin.

2. The image value of the CCD of the digital camera. CCD is the heart of digital cameras and one of the main factors affecting the manufacturing cost of digital cameras. Therefore, it has become an important criterion for classifying digital cameras. Currently, entry-level products are 3-5 million pixels, while commercial and semi-professional users tend to have products with 5-10 million pixels or more.

3. Digital camera zoom. Optical zoom is a real zoom and will not affect the imaging quality of the photo; while digital zoom is an electronic zoom, which is partial magnification at the expense of photo clarity.

4. Digital camera battery and power consumption. Digital cameras consume more battery than traditional cameras because they have an LCD display and a built-in flash. AA batteries are cheap and can be purchased anytime and anywhere, but the battery will run out of power after a short period of time. Therefore, it is best to choose a model equipped with a rechargeable lithium battery. Currently, mainstream digital products are all designed with lithium batteries, and a complete range of charging equipment is provided as accessories.

5. Additional functions. More functions mean more fun and more uses with your digital camera. For example, many digital cameras have a video output function that can be connected to a TV to browse photos; some can set the startup image and shutter sound like a mobile phone; some can have a short-term digital video recording function. Digital camera drivers should be easy to install and should allow for quick image downloads, photo previews, and more. For example, the software that comes with Canon digital cameras has very complete functions. It can manage pictures by categories, has a variety of settings when printing, and can also simply modify pictures.

The image sensor is the decisive factor in camera performance. Generally, 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 lack of pixels in the image sensor, some manufacturers use software interpolation to increase the pixel value of the image. In fact, this interpolation method can be implemented in almost all image processing software, so it has little practical significance. When purchasing, be sure to base your purchase on the hardware pixel value of the image sensor rather than the maximum pixel value of the output image.

Digital cameras record photographic information on a semiconductor element called a CCD (Charge Coupled Device), rather than on the film of a silver halide camera. CCD size refers to the diagonal length like a TV set, 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 (4.0mm×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 An inch is equal to 2.54cm. The CCD of a digital camera uses the same representation method as the picture tube of a television.

2. Four Basic Principles for Buying a Machine

●For ordinary home users, if they are limited to home entertainment and pay great attention to practicality, powerful functions and durability The high cost performance is the preferred factor. Currently, the 3-megapixel and 5-megapixel models that dominate the market can meet imaging needs. Multiple shooting modes, a wide ISO value setting range, and high-speed and accurate focusing are necessary features, and the metal casing ensures durability. is also an essential consideration.

●For those consumers who pursue fashion and avant-garde, the close combination of appearance design and highlight functions is the preferred standard. Compact appearance, bright colors and comfortable hand feel are must-haves, and some highlight functions such as macro shooting function are the icing on the cake for this type of product.

●If you are a professional-level user, the most important thing is the ultimate pursuit of imaging quality. Manual operation is a must. Interchangeable lenses, a CMOS image sensor of more than 6 million pixels and multiple image recording modes are the guarantee of high image quality. If you also have an explosive kit price of less than 10,000 yuan, This will make more professional photography enthusiasts flock to it.

●The last thing to consider is where to buy. A regular digital camera sales counter will guarantee the "originality" of your camera. Brand effect should be considered when purchasing, as it is the main guarantee for the overall quality and after-sales service of a digital camera.

3. Preparation steps for buying a camera

Step 1: Clarify the use and purpose of buying a camera

It is very important to determine the use and purpose of buying a camera , only by understanding our own needs can we choose and purchase the machines we really need. Otherwise, you may spend a lot of money to buy a camera, only to find that the functions cannot meet your requirements, or there are too many functions that you cannot use at all. We can think about what we buy a digital camera for. For example: some friends buy digital cameras to travel; some want to learn photography; some want to take macro photos; of course, some want to take close-up portraits or take photos of their newborn baby. In short, you must consume clearly.

The issue of photo output also needs to be considered in advance, whether you need to print large photos or just view them on the screen. By considering this, we can decide how many pixel machines we need to buy. If we just watch on the screen, then a 3 million pixel machine is enough. If we want to print, and we want to print to 10 inches or more, then we need to buy a camera with as high a pixels as possible.

Step 2: Determine the psychological price

After deciding the use and purpose of purchasing the camera, we should decide an affordable psychological price according to our own financial ability, such as 3,000 ~4,000 yuan or 6,000-7,000 yuan, etc. This can help us save a lot of time and make our choices more purposeful. DC is still a luxury product, so everyone must do what they can. There is no point in comparing with others. Just use enough.

Step 3: Collect information through various channels

Preliminary data collection is very important, which allows us to have a certain understanding of the machine we want to purchase. There are many ways to collect product information. First of all, many manufacturers will have certain promotional posters when they launch digital cameras. We can go to the seller to take a look. Secondly, media advertising is also a very important way. Today, there are many digital camera advertisements in IT newspapers and periodicals. We should pay attention to them. Thirdly, many digital magazines or some newspapers now have a certain amount of space to introduce digital cameras or evaluate digital cameras. We can also buy some and read them.

If possible, you can download the manual of the corresponding camera and take a look. This is very beneficial for buying a machine: on the one hand, it allows you to become more familiar with the machine, and on the other hand, it allows you to be prepared and able to perform basic operations when purchasing. I love reading manuals myself.

Technical information allows us to understand the appearance, functions and other information of the digital camera. And we should look at the actual photos taken. This way you can know the characteristics of the DC you are interested in, such as color, picture quality, etc. We can go to the digital photography website to learn about this.

Step 4: Roughly decide on the model

Collecting product information is very important, which allows us to fully understand the characteristics of the digital camera. But just by 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 prototypes placed in the window or counter. The real machine may look different from the one in the photo, and may look better. We can also watch others buying machines and listen to what others have to say. Of course, we can also ask the merchant to take out the machine and actually touch and operate it.

You need to see the machine and ask about the price. When asking about the price, you should note that the merchant's quotation usually leaves room for counter-offering. You should also ask whether the price they quoted is the price of licensed goods or parallel imports.

Step 5: Choose the time to buy

After deciding on the machine you want to buy, you need to choose the "auspicious day" to buy the DC. The "auspicious day" I mentioned actually means that you need to know the right time. The prices of digital products are changing rapidly, so it is still very important to judge the market. But one thing is clear: avoid buying before the holidays as much as possible. There must be many people buying machines before the festival, and the price will not be cheap.

A must-read when buying a camera

When buying a camera, we need to inspect it carefully to avoid buying defective products or being deceived by JS (profiteers). Here we give a detailed machine inspection step. As long as you follow the instructions below, there will be no problem:

1. Never pay money to JS first, be sure to check it after Pay again;

2. Check whether the packaging is very old. If it is very old, it may have been replaced by someone else, or it may be a product that has been stored by JS for a long time;

3. After opening the box, check whether the accessories inside the box have been used or have been obviously dismantled; pay special attention to whether there are scratches on the battery pins;

4. Check the appearance of the machine . Check to see if there are any scratches on the fuselage, including the lens, LCD, EVF and casing;

5. Try shooting and use the zoom to see if you can take clear pictures from both distance and near. If you are not familiar with the machine you are about to buy, you can use AUTO mode to shoot when testing the machine. In addition, you have to try the flash;

6. Then take a closer look at the LCD and EVF to see if there are any dead pixels. You can block the lens slightly with your hand so that you can see a more solid color image, or face white paper and dark paper.

7. CCD is a key component of DC. If there are bad pixels on it, it will affect shooting. Since it is difficult to see clearly the dead CCD pixels directly on the DC, you need to import the pictures to the PC to view them again. If the merchant does not have a computer, it is recommended to negotiate a certain replacement period with the merchant, and then go home and test it safely;

How to test for dead pixels

Before I talk about how to test for dead pixels , we want to explain what a bad pixel is. To put it simply, it is a point on the CCD that will never be sensitive to light, or this point will always be on. Usually there are most cases where it is always on, and there are very few cases where it is not on. So why do bad pixels occur? This is related to the manufacturing of CCD. Although today's technology has become very advanced, CCD still cannot guarantee a high yield rate. Just like LCDs, there may be imperfections. So we need to test the machine after buying it.

The test for bad pixels is actually relatively simple. We can use two methods to test: one is to look at the original image with your eyes. In fact, this method is more intuitive, but you have to be careful, otherwise it is easy to miss points. The second is to use software testing. The most popular dead pixel testing software now is DEADPIXEL. Usually wherever DC is sold, if there is a computer, this software will be available.

Before testing, we first need to take some completely black photos. Ordinary photos cannot be tested. This is very critical. For machines with lens caps, we only need to cover the lens cap to shoot. If there is no lens cover, such as Casio, etc., then we can put a piece of thicker paper on a flat table, put the DC lens downward, and buckle the lens on the paper to shoot. It should be noted that light must not enter the lens, and do not use too much force, as this may easily damage the machine.

We can set the parameters when shooting to the maximum aperture and ISO 100. As for the shutter, we need to choose 1/60 and the slowest shutter. That is, one picture is taken at different shutter speeds.

After the shooting is completed, 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 photo we need to test. Then we press the TEST button and the results will appear. If the 1/60 photo test shows a lot of noise exceeding 10, then try to change it, otherwise it may affect the shooting.

Check whether all the accessories are there. Usually there is a list in the packaging box, which details how many random accessories there are. We can check it and count it.

Purchasing accessories

After buying a DC, of ??course you also need to buy certain accessories so that we can shoot better. Accessories are actually quite important. If they are not purchased well, they may affect our normal shooting. Usually we may need to buy memory cards, batteries and chargers, UV and adapter rings, camera bags, tripods, etc. Some people like to buy all digital cameras at once. I think if you buy these from a place that sells DC, the price will definitely not be cheap. In addition to memory cards, you should go to a specialized photography equipment store to buy other items, which are not only reliable in quality but also cheaper. Below we will talk about what you need to pay attention to when buying these accessories by category.

Memory card: When buying a memory card, you should consider your daily shooting volume and combine it with your own DC to determine the capacity of the card you need to buy. Secondly, we need to consider the brand of the card. There are many card brands on the market at present, and the card brand determines the quality of the card to a certain extent. For example, although Kingston CF card and TOSHIBA SD card are not very fast, their quality is definitely top-notch and their compatibility is also good. Again, we have to consider the speed of the card. There are two types of cards on sale now: normal speed and high-speed cards. If you need to take photos in RAW or even TIFF format, try to buy a high-speed card.

Battery and charger: There are generally two types of batteries used in DC, one is rechargeable lithium battery and the other is AA (AA) nickel metal hydride battery. My suggestion for rechargeable lithium batteries is that you go to regular stores to buy them. On the one hand, they have quality assurance, and on the other hand, there is a high probability of buying fakes. In terms of nickel-metal hydride batteries, the current GP Speedmaster batteries are not very expensive and are of first-class quality. Of course, domestic products are not bad either. We try to buy one with a larger capacity, such as 2000mAh. As for the charger, many digital cameras now come with it as a gift, so I won’t go into detail here.

UV and adapter ring: The main function of UV for digital cameras is to protect the lens. Whether you need to buy this or not, I think it first depends on what kind of machine you are using. If the machine is relatively small, then it is better not to consider it. Because usually UV can be installed on the machine through an adapter ring or barrel, which increases the size of the camera. If the machine itself is relatively large, such as Canon EOS350D, this is more suitable. There are many brands of UV, and it is recommended to consider multi-layer coating. When buying UV, we also need to consider the caliber of the UV. If you are not very familiar with this, you can buy it with your camera. In addition, after installing UV, the original lens cap that comes with the camera may not be able to be replaced. We need to get another one.

Photography bag: Be sure to consider the location of the accessories, and take the machine with you to buy it. Only in this way can you buy the right one. The bigger the camera bag is not the better, but the fit is the best. In addition, you should also pay attention to the material of the bag and try to buy a waterproof bag.

Tripod: When choosing a tripod, pay attention to its stability and avoid buying one that is wobbly. Also keep an eye on the weight, which may not be an issue if you're strong and in need of exercise. The most popular one on the market is the Weifeng brand. This brand’s tripods are relatively cheap and pretty good. The imported brand Japan's Admiralty has a long history, and many top international photographers choose this brand. The price is not very expensive either.