Inadvertently, digital cameras have appeared in all areas of our lives, and increasingly accepted by the majority of consumers go use. When you walk in the street or watch major sports competitions, cultural performances, hand-held digital cameras are not difficult to find people.
However, the majority of consumers of these carefully packed new models of digital cameras, the new product is still a lack of understanding. And the purchase of a digital camera, use, maintenance involves many aspects of knowledge, for most consumers, a digital camera or a mysterious high-end products. Therefore, I will buy digital camera, use, maintenance, maintenance and other aspects of experience and knowledge to sort out to share with you, allowing you to provide a general understanding of the digital camera. To identify these knowledge, it is necessary to know how to seven points.
First, out of the high-pixel errors
Pixels as one of the criteria to measure the quality of a digital camera, consumers are often considered to be to buy a digital camera assessment focus, many consumers and therefore into the high pixel errors, blind pursuit of high pixel, the pixels look became The only standard to measure the quality of a digital camera. Digital cameras with CCD or CMOS photosensitive, the number of pixels of the captured image depends on the number of the photosensitive element CCD or CMOS camera chip, theoretically, more photosensitive unit, and the images will be more clear. However, due to the area of the photosensitive element of the digital camera is much smaller than the area of traditional film, in a limited area of the chip on the increase too much photosensitive unit there will be a lot of problems, such as image signal-to-noise ratio decreases sensitivity to reduce.
As we all know, digital cameras need to rely on the internal image processing engine to reduce color error. The principles of the digital camera imaging and traditional camera has a difference in the nature, the data obtained by the photosensitive element must be processed and combined to generate a final image file, and the calculation method of the processing engine directly affects the quality of the final image. Therefore, the pixels can indeed be regarded as the level of the digital camera important one of the criteria, but not the only criteria, we need a digital camera indicators to comprehensively examine the quality of the digital camera.
Second, the importance of sensor size
There are many factors that affect the image quality of digital cameras, which, the photosensitive unit size of the digital camera sensor imaging is great. The larger the size of the photosensitive cells, the photosensitive member is more sensitive to light, the smaller the noise of the signal generated, and would be more excellent in the reproduction of highlights and shadows, and higher contrast. The photosensitive cells of the excessive increase in the limited area on the photosensitive member, will lead to the photosensitive cell is too small to bring the image SNR decreases, the sensitivity is reduced and other issues.
So, how do we know the size of the photosensitive cell? We know, is equal to the number of pixels of the digital camera image the photosensitive unit number on the CCD sensor in the camera, therefore, if the same number of pixels, the large sensor size used by digital cameras The individual size of the photosensitive cells is naturally large. Such as the pixel digital camera Canon PowerShot G2 and EOS 1D models are 4,000,000 and 4,150,000, PowerShot G2 is 1/1.8 inch CCD, the size of each photosensitive cell only 3.125 square microns, while the EOS 1D using the area of 28.7mm × 19.1mm large CCD, a single photosensitive cell area of 11.5 square microns, which is able to achieve the highest equivalent sensitivity PowerShot G2 ISO400 EOS 1D able to achieve the highest equivalent sensitivity ISO1600 reasons.
Third, the importance of the lens
It can be said that the lens is the soul of a camera, the digital camera is certainly no exception, either an optical camera or digital camera, the lens is the most one of the elements can not be ignored.
On the surface, digital cameras due to the limited resolution of the photosensitive element, in theory, the optical resolution of the lens requirements is relatively low, but because ordinary digital camera is the CCD or CMOS sensor, the light-sensitive area of its area than traditional film much smaller, so the the lens resolution requirements more stringent. Otherwise, digital cameras, even if there are a high number of pixels, the image quality is still the reason because lens and relatively poor. In other words, the analytical capacity of the optical lens digital camera must be better than the resolution of the photosensitive element.
In fact, the degree of the lens structural complexity of the digital camera and the requirements of the production process, is not lower than traditional camera lens, it is mainly by the multi-group lens, the higher the image quality, the lens is more. It is hard to say what kind of lens is the best, but with large-caliber, multi-piece group contains high-quality lens aspheric lens and high-quality coating is the best choice for users requiring perfect image quality.
Currently, the major lens manufacturers in the market, including two series, one for the Japanese manufacturers, including brands such as Nikon, Canon and Pentax; another German manufacturers, including brands such as Leica, Zeiss and Schneider. Japanese manufacturers are cost-effective, while the high quality of German manufacturers lens imaging lens, but relatively speaking, the price is also more expensive.
In addition, the digital camera lens material is divided into two types of glass and plastic, some companies have stressed that their camera lens glass material, good transmittance, the projected image is clearer. But in fact, the glass lens is not necessarily than plastic lenses clearer images, glass lens camera may also increase the weight, or should the purchase from various aspects to consider, not limited to this.
Fourth, pay attention to the details of the zoom function
In the purchase of a digital camera, the zoom factor is generally the focus of consumers. Larger zoom digital camera more flexibility, but not simply look at the size will be able to know the digital camera shooting. Zoom the divided optical zoom and digital zoom, we first have to pay special attention to the range of the optical zoom, the smaller the minimum focal length of the camera, the greater the scope of its wide-angle shot, conducive to shooting big scenes, larger maximum focal length is far camera capability. Focal length range of 38mm ~ 114mm and 35mm ~ 105mm lens 3x zoom lens, but obviously lost the ability to shoot a big scene of 38mm to 114mm lens, 35mm ~ 105mm lens practicality necessary than the former is much higher .
In addition, traditional camera, digital camera also offers a digital zoom function, digital zoom and optical zoom intake for larger image and science fill the empty part of a lot of different digital zoom, which is the so-called interpolation Law enlarge. Need to pay attention to, the interpolation more components sacrificing picture details more, lower-definition. Therefore, the digital zoom does not have much practical significance, therefore, in the purchase of a digital camera, to focus on to look at the optical zoom range, do not listen to the merchants irresponsible propaganda, mistaking the digital zoom function can compensate The deficiencies of the optical zoom range.
5, the speed of the memory card
Most manufacturers comes with a digital camera memory card quality is quite good, but unfortunately, these included the general capacity of the memory card are very small. Therefore, you mostly need to buy a digital camera, an additional optional large-capacity memory card, if the purchase is the memory card of the brand-name company, quality is no problem, but most of the cheap memory card, general electronic market bulk bring your cameras to buy a memory card marked or unknown products, difficult for consumers to go up to the judge the quality of the memory card from the appearance, therefore, experienced users will be able to rest assured, the actual test.
Test, you should pay special attention to test the speed of the memory card, the different quality of the product is not the same speed regardless of which memory card you use, slow memory card will make your digital camera storage takes photos more time is a very serious impact on the performance of the camera.
Simple test, you can shoot continuously fixed scene, recording the speed of the memory card. Conditional user can also use a card reader to test, but only if the speed of the reader interface to transfer data faster than the speed of the memory card to test, the best reader USB2.0 interface for testing.
Six, battery selection
Whether using traditional film cameras or digital cameras using memory cards, batteries are very important, especially for being referred to as a digital camera for the large electricity. Some digital cameras use less than an hour will run out of battery power, if you use the LCD viewfinder, then the battery consumption faster. How to choose the camera a reliable electricity is an important issue that you need to consider the purchase of the camera, but pay attention to what your camera battery is the first thing you need to consider, figure out your camera can use the after battery types, you can begin to consider which one of these batteries is more suitable for you.
Under normal circumstances, the digital camera can be used dry batteries, alkaline manganese batteries, nickel-cadmium batteries, nickel hydrogen batteries, lithium-ion batteries, and lithium batteries as its power. Many people used dry batteries, carbon zinc dry batteries or zinc chloride dry cell, due to the lack of energy density, is generally used for smaller power consumption of electronic products, used to drive your digital camera probably make you disappointed. While the lithium-ion battery and lithium battery technology status, performance are better, but the price is slightly higher, use more meticulous, especially lithium-ion battery, but also with the special charger.
Many digital camera users to use alkaline manganese batteries, alkaline batteries is generally said, its large capacity, the current strong and lasting use. However, the For fixed voltage digital camera, alkaline batteries appeared to be inadequate, the long-term use will make difficult for the average consumer to bear the costs. In contrast, nickel-cadmium batteries, nickel hydrogen batteries currently in battery manufacturing technology is relatively mature, it is electric high capacity, long cycle life, large depth of discharge, resistance to overcharge and over-discharge, low internal resistance and memory effect is not Obviously, the prices are more reasonable. For most users, the nickel-cadmium batteries, nickel hydrogen batteries will be a good choice, it can significantly reduce the cost of the use of digital cameras, and environmentally friendly.
7, CCD and CMOS selection of
Traditional camera with film photosensitive principle different from the stored images, the digital camera is to use a photosensitive member to be irradiated through the lens to the chip light is converted into an electric charge, and then the electric signal into a digital signal after processing, and then after the image processing engine processing the digital signal to a certain format compression produce digital photos stored in the cache. The importance of the photosensitive element is self-evident, both CCD and CMOS digital cameras currently on the market use the photosensitive element, they are very different in function and performance, due to popular digital cameras when, CMOS technology is not very mature, so most of the consumers the idea that CCD is better than CMOS, CMOS sensor is only suitable for use in mobile phones or other occasions not so high image requirements.
In fact, this is a wrong perception. Indeed, most digital cameras use a photosensitive element CCD, This special semiconductor material through the surface of the photosensitive member to convert the light into an electric charge, can produce low-noise, high-performance imaging, it has been widely recognized and applied. But actually, the CMOS photosensitive member also has many advantages, CMOS semiconductors to convert the light, but different and CCD, CMOS each of the photosensitive member has a charge is converted to the electronic signal amplifiers, CMOS can in each pixel basis for signal amplification, this approach may save any invalid transfer operation, so only a small amount of energy consumption, while the noise is also decreased. Well-made CMOS sensor imaging results is not worse than the traditional CCD, therefore, can not be used in digital cameras to measure the quality of a CCD or CMOS sensor CMOS photosensitive element is good or bad only is the production quality and technical maturity. CMOS digital cameras produced by Canon EOS 10D is a quasi-professional-level digital camera.
没有评论:
发表评论