What is the use of SLR camera lens?
SLR camera according to different requirements can choose a different lens, rather than a consumer class DC to kill the world, mainly in order to improve the image quality.
Because the greater the optical zoom factor, the greater the impact on the imaging, so the general SLR zoom zoom are relatively small, in order to adapt to different focal lengths, the focus of the segment made of different lenses, such as 18-50,50-100,100 -300, etc., called the small focal length wide-angle lens, used to shoot the scene of the scenery and tall buildings, large focal lengths called telephoto lens, telephoto lens according to the different focal lengths and a small telephoto and long telephoto
In addition, in order to further improve the image sharpness, there are some zoom lens can not zoom, such as the fixed focus of the 50 head comparison, in order to further improve the sharpness of the image, Suitable for portraits, fixed focus general aperture do a lot, you can have a good background blur effect. Of course, even the same focal length of the lens is also very different, such as the largest aperture of the difference, the price difference between the many large aperture lens can better adapt to the dark environment shooting, background blame Ye Hao.