Look at this. It will help you a lot.
Many friends will encounter a dilemma when choosing digital cameras-how many pixels to choose from tens of thousands? How many times optical zoom is needed? What size LCD screen should I choose? Whether there is a manual function and so on. Indeed, there are many types and brands of digital cameras at present, and the frequency of upgrading is getting faster and faster. Everyone should not only rack their brains when buying machines, but also need to keep learning. The following questions are typical when many friends buy and use digital cameras. I hope the answers to these questions will help readers to know more about digital cameras.
First of all, what are effective pixels, CCD size and image resolution? The relationship between each other?
1. What is a valid pixel?
Answer: When a digital camera is imaging, the edge of the photosensitive element will be blurred because of the diffraction of light. In order to ensure the imaging quality, this part of the imaging on the photosensitive element will be abandoned, so the photosensitive unit 100% cannot be used, and this part of pixels used to obtain the final image is called effective pixels.
2. What is CCD size and what is its function?
A: CCD or CMOS, the key component of digital camera, is also called "image sensor", which is equivalent to photosensitive film. The CCD size refers to the diagonal length of the photosensitive element, and the commonly used unit is inch. Common ones are11.8 inch, 1/2.5 inch and 2/3 inch. The larger the CCD size, the better the light collection effect, the more information recorded in the picture, and the richer the details retained, so the image is more perfect and beautiful.
3.3 What does it matter? CCD size and pixels?
A: The size of CCD is related to the number of pixels, but this is not always the case. The d70 of professional digital SLR Nikon has only 6 million pixels, but the CCD size is 23.7×15.6 mm; Nikon coolpix P3 digital camera has 865,438+megapixels, but the CCD size is only 5.38× 4.39 mm (11.8 inches) (the mainstream size in the market now), and the difference between the two CCDs is nearly 10 times. To be sure, the image quality of D70 is much better than that of Nikon coolpix P3, and the bigger the image, the more it can prove this. So when buying a digital camera, don't blindly pursue high pixels, but also see how big its CCD size is! At present, the maximum size of CCD and CMOS (except the digital back dedicated to 120) is the same as that of 35 mm traditional film, that is, 24× 36 mm, so it is also called "Quan Huafu" CCD.
4. What is image resolution?
A: Image resolution is the image size and size that a digital camera can choose, and the unit is dpi. Common ones are 640x4801024x768; 1600 x 1200； 2048 x 1536. In two sets of imaging numbers, the former is the length of the picture and the latter is the width of the picture, and the pixels of the picture are obtained by multiplying them. The length-width ratio is generally 4:3. The larger the resolution, the larger the area of the picture.
5. What is the relationship between image resolution and pixels?
A: Having finished the definition of pixel and resolution, let's take a look at the relationship between them. Careful friends may have found that pixels are directly proportional to resolution, and the larger the pixels, the higher the resolution. Give an example! As mentioned earlier, pixels are divided into effective pixels and CCD pixels.
Generally speaking, the maximum image resolution of a 5 megapixel digital camera is 2592×1944 = 5.04 million pixels.
Generally speaking, the maximum image resolution of an 8-megapixel digital camera is 3264× 2448 = 7.99 million pixels.
It can be seen that the higher the pixel, the higher the resolution of the maximum output image.
To sum up, pixels are only related to the size of the photo output image, and have little to do with the image quality. The higher the pixel, the bigger the photo can be developed, not the clearer the photo. 5 megapixel camera is the mainstream model now, which can fully meet the needs of family photography. Higher pixel products only provide you with a larger magnification size. According to my personal experience, a 3-megapixel digital camera is enough for home use, and the resolution of 2048 x 1538 can print 8-inch high-quality photos. The printing accuracy of a print shop is generally 180 DPI, so a 3-megapixel camera can theoretically develop 1 1.3 inch photos. Now you know how many pixels you bought! (The calculation formula is the long side of the image resolution/the washing accuracy of the washing and ironing shop = the maximum photo size obtained), but in online communication, usually only the resolution of 800 x 600 is enough to ensure the clarity of the photos. In addition, the investment in using low-resolution digital cameras on memory cards in the later period is also relatively small. If the photos taken are used for other purposes such as competition or printing, in fact, 5 million pixels can meet the demand.
6. What is digital zoom and what is optical zoom? What is the difference? Is it as far away as possible?
A: Optical zoom-Digital cameras rely on optical lens structure to achieve zoom. The optical zoom mode of a digital camera is similar to that of a traditional 35mm camera, that is, the scene to be shot is enlarged and reduced by moving the lens. The larger the optical zoom coefficient, the farther the scene is photographed. When the image plane moves in the horizontal direction, the visual field and focal length will change, and the farther scenery will become clearer, making people feel that the object is moving forward.
Digital zoom-it uses the built-in program of digital camera to enlarge the image through software. In fact, digital zoom does not change the focal length of the lens. (Principle: Use software to judge the colors around existing pixels, and insert pixels added by special algorithm according to the surrounding colors. )
Optical zoom is a real pixel, which can restore distant scenes without any quality loss, while digital zoom is at the expense of photo quality. The more you use it, the greater the loss, so in the actual use process, digital zoom is hardly used.
Many dealers like to associate large zoom with professional digital cameras, and even associate large zoom cameras with boutique digital cameras. This view is a bit too one-sided.
Although for digital camera enthusiasts, the attraction of large zoom is certainly not small, but we must understand that the focal length is not the ultimate goal, the most important thing is the focal length range covered by the lens. Generally speaking, it is appropriate to use a medium focal length (85- 135mm) when shooting people, and it is better to use a wide-angle lens (18-40) when shooting landscapes and buildings.
However, a large zoom digital camera often can't have both. The reason is that the large zoom camera has a short depth of field, although it can stand out from the main body, but the focusing speed is slow and the focusing accuracy is not high. If the camera is slightly inaccurate in focusing, the subject will be blurred (that is, out of focus). In addition, because the spatial range of the scene is small, the shot image is narrower than the standard lens with the same distance. The wide-angle end of a large zoom camera is prone to serious dispersion and image distortion. Because of the low cost and poor lens quality of large zoom cameras, it is difficult to focus all kinds of colors on one point, so the problem of sub-spectrum also occurs from time to time. If there is no anti-shake function, as long as the light is slightly insufficient, it is difficult to ensure that the hand does not shake, and the direct consequence is that the picture is blurred.
7. Is manual work really that useful?
A: Once upon a time, fully manual digital cameras became popular in the low-end digital camera market, especially the Canon A series, which was in full swing before. Some of their characteristics are low price and comprehensive functions. Many high-end digital cameras over 6000 yuan are equipped with. Manufacturers just grasped the consumer's psychology that "more functions are better than less functions, and they spend the same amount of money anyway", and made a lot of publicity on functions.
In fact, consumers who have actually bought such digital cameras should have the most say. Before buying, they went to the full manual function. But after buying it back, after several curious attempts, I found that the photos taken were very bad, either overexposed or dark. After failing n times, they still obediently set the mode to P or automatic, and finally regretted it. ...
In fact, there is absolutely no need for home users to choose a digital camera with full manual function, because the probability of using it in actual combat is very small, and now many cameras are equipped with the function of using more humanized scene mode. Once the full manual function is locked, there is little room for choosing a camera.
Key: How much photography knowledge do you know first when buying a mobile phone camera? Want to learn? Buy an automatic camera if you don't want to buy it.
8. Is the screen as big as possible?
A: If you want to list the keywords of the digital camera market in 2005-2006, then "big screen" is definitely inevitable. With the trend of digital cameras becoming more fashionable and thinner, large screen has become a standard to measure the quality of digital cameras and a sword for manufacturers to promote cameras.
In fact, there are many secrets hidden behind the big screen, such as LCD pixels. At the end of 2004, many brands of digital cameras were upgraded and new models were introduced. Compared with the old models, their screen sizes have become larger, but the pixels have not changed. The display effect of these improved digital cameras looks rough and grainy, and it doesn't feel like the small screen before improvement. In addition, the power consumption of the large screen also increases. If the battery capacity remains unchanged, the circuit is not optimized, and only one screen is changed, which will have a great impact on battery life. Some large-screen cameras have shadows, so pay attention when buying them! At this point, I hope that consumers must see the parameters clearly when buying, and don't be confused by the word "big screen".
Several problems that must be considered before buying a camera;
1. What's the purpose of buying a camera? What is it mainly used for shooting? It is very important to choose the type of camera, whether it is an entertainment camera or a quasi-professional camera. If it's just for family commemorative photos, the more convenient the better. If you are interested in photography, you can choose a camera with some manual functions.
2. How much are you willing to invest in a camera? This is also a very practical problem, which is directly related to the choice of camera. The choice of home camera is generally around 3000 yuan, which is the most practical. It is also the mainstream price in civil cameras.
3. Defining the positioning and product characteristics of each camera manufacturer is very useful for choosing the right product.
● Sony is the dominant player in the home appliance and film industries. As a manufacturer of CCD and LCD, it has an unshakable position in this technology. Sony's digital camera has always been characterized as a fashion leader in the industry, and his T series products have led the trend of ultra-thin cameras. The industrial design of each camera is almost perfect, and fashion is Sony's slogan and feature.
Canon is a veteran of the camera industry, with a long history of camera production, and is very mature in optical quality and camera ergonomics. The professional camera designed is the mainstream model in the industry. In the civil field, Canon's camera combines fashion and high quality, and it is a successful manufacturer of image quality and appearance treatment, and its product series is very perfect. High imaging quality and high mobility are the characteristics of Canon.
● As another veteran of the camera industry, Nikon's development is slower than the first two, because its relatively stable development ideas have been stable in the tide of digital cameras in recent years. The civil field is the golden mean, and the professional field has been fighting for a place with Canon. Nikon is famous for its quality, and its appearance may not be as fashionable as Sony's, but its handling and imaging quality is definitely leading. Price is one of Nikon's advantages. At present, Nikon's full range of civil cameras are below 3200 yuan, which is a world-famous brand with good combination of practicality and quality.
● Fuji and Kodak are enterprises transforming the film industry into the digital field, both of which are in the low-cost field. The price of their products is the lowest among camera brands, and the price is a selling point of Fuji and Kodak.
● Samsung is an outstanding new army in the past two years, and its style is very similar to Sony. It is a low-priced army of fashionable products, and its fashionable products and low prices have attracted many student consumers, which is also their customer orientation.
● In addition, Pentax, Ricoh, Casio, Panasonic and other brands have their own customer groups, mainly focusing on low-cost and practical positioning. Pentax's popularity in optics, Casio's specialty in fashion and thinness, Panasonic's characteristics in anti-shake and large zoom, and wide-angle Ricoh cameras all have their own space in the market.
The function of the product is clear, and every consumer can choose the right product according to his own preferences.