Invite experts on digital cameras.

1. SLR refers to single lens reflex, which is the most popular framing system today.

In this system, the unique design of the mirror and prism enables the photographer to directly observe the image passing through the lens from the viewfinder. It can be seen from the structural diagram of a single-lens reflex camera that the light passes through the lens and reaches the reflector, and then refracts to the focusing screen above to form an image. Through the eyepiece and pentaprism, we can see the scenery outside in the observation window. When shooting, press the shutter button, the reflector will pop up, and the shutter curtain in front of the film will be opened at the same time. The light (image) passing through the lens will be projected on the film to make the film sensitive, and then the reflector will immediately return to its original state, and the image can be seen in the viewfinder. This structure of the single-lens reflex camera ensures that it is shot through the lens, so that the image seen in the observation window is always consistent with the image on the film, and its framing range is basically consistent with the actual shooting range, eliminating the parallax phenomenon of the paraxial head-up framing camera. From the perspective of learning photography, it is very conducive to intuitive framing and composition.

Because the whole imaging system of SLR (focusing and shooting) is a lens, there is no parallax, that is, framing and imaging are the same! Traditional machines are mostly paraxial framing! ! Secondly, because the imaging system is used as the lens, the coordinated response is faster than that of ordinary machines, so the SLR camera is more suitable for shooting high-speed moving objects! You won't miss the beautiful scenery because the camera is slow. Thirdly, SLR uses a lens change to form different photography systems. For example, you can change a wide-angle lens, lengthen the lens, add a color film and choose a macro lens. Meet your different needs! You won't miss the beautiful scenery because of the limited lens of the machine!

Finally, because SLR cameras mostly use pure natural crystal or fluorite polished lenses, the price is much more expensive than ordinary glass and plastic lenses. Some even use ultrasonic motors to adjust the lens, the vibration is smaller than that of mechanical ones, and some have their own anti-shake patents (such as Canon's EF series lenses), especially the so-called pure natural fluorite lenses with red lines, which are between 30,000 and 50,000 yuan.

DSLR digital camera refers to a single-lens reflex digital camera, that is, digital, single-lens, lens and reflex. Representative models in the market are common in Nikon, Sony, Canon, Pentax, Fuji and so on. This kind of camera is usually big and heavy.

Models that use electronic viewfinder EVF are also classified as SLR, but generally "similar" is added or EVF framing is indicated, such as Olympus C-2 100UZ and Fuji Finepix 6900. In the working system of SLR digital camera, after the light reaches the reflector through the lens, it refracts to the focusing screen above to form an image. Through the eyepiece and pentaprism, we can see the scenery outside in the observation window. In contrast, ordinary digital cameras can only see the captured images through the LCD screen or electronic viewfinder (EVF). Obviously, the directly seen image is more conducive to shooting than the processed image.

A major feature of SLR digital cameras is that they can change lenses of different specifications, which is an inherent advantage of SLR cameras and incomparable to ordinary digital cameras.

In addition, SLR digital cameras are now positioned as high-end products of digital cameras, so the area of photosensitive elements (CCD or CMOS) related to the photographic quality of digital cameras is much larger than that of ordinary digital cameras, which makes the photosensitive area of each pixel of SLR digital cameras much larger than that of ordinary digital cameras, so each pixel can show more detailed brightness and color range, which makes the photographic quality of SLR digital cameras significantly higher than that of ordinary digital cameras.

Simply put, SLR digital cameras are not suitable for any users. First of all, it is one thing to have the necessary professional knowledge. Secondly, to make good use of SLR digital cameras, we must match different types of lenses, which is likely to make the cost of lenses higher than the cost of buying digital cameras.

Moreover, when traveling abroad, the weight of camera bag with lens group is much higher than that of ordinary camera, which will become a serious burden in the travel process. In addition, when changing the lens of SLR digital camera, the photosensitive element will be directly exposed to the air, so we must also pay attention to the maintenance of the camera when using it. Therefore, although the shooting quality of SLR digital cameras is higher and the price has dropped a lot now, it is not suitable for all users, and users should choose according to their own needs when purchasing.

One of tennis backhand techniques

Tennis backhand techniques include one-handed backhand (referred to as' SLR') and two-handed backhand (referred to as' double backhand').

SLR is elegant, double-reverse stable.

In fact, the attack power of SLR is greater than that of double reaction. Before Nadal was mature, Federer's SLR was basically the most important weapon of Tianwang, with large attack angle and great flexibility. Moreover, at the peak of Federer's life, he felt very good. Not only did the SLR slash fast, but he caught it. The SLR line is also arbitrary. The ball landed only a few centimeters around the sideline, which is not a good memory or a beautiful artistic appreciation.

Sampras, Kurten, Haining, Mauresmo and Federer are all the best in the world. They are all SLR, and they are all famous figures who have dominated an era or at least a year.

SLR is not only elegant, but also superficial. In fact, the combination of SLR and hairstyle is the most powerful. I remember Agassi once laughed at Sampras and said: The stupidest thing about that guy is to turn his hands into one. However, in order to cooperate with SLR, Sampras resolutely and thoroughly implemented the tactics of serving the internet. No matter what the ball is, no matter how others return it, he always goes online directly. In fact, Federer has to study hard for this determination.

Nowadays, among the top players in the men's open, the use of SLR has become less and less, and the most are Federer, Blake, Gasquet, Gonzalez, Wawrinka and Uzzini. The same is true of women's tennis. After Haining retired, only Spanish star Navarro and French veteran Mauresmo were left.

Second, you can buy a Canon 450D, and you can use it as a basis to improve while playing.

Third, China Photography Network

Fourth, it depends on your own price! 450D canon,