单反镜头数据常识（SLR Lens data common sense）.doc

单反镜头数据常识（SLR Lens data common sense） SLR Lens parameters, there are several items need attention. A. The parameter meaning of the lens is approximately as follows: Take AF 24-85/2.8-4D IF as an example: 1) the front of the AF, which means automatic focus, can be used for entry-level models above, and the entry model requires the use of AF- S lens (if it is also marked with VR, which means that the camera has anti shake function). 2) 24-85 represents the focal section, and different focal sections are suitable for shooting different subjects. The smaller the number, the greater the angle of view, and the smaller the angle of view. For example, 70-200, the angle of view is narrow, suitable for shooting distant objects. 3) the 2.8-4 at the back of the line is the aperture, and the D indicates the lens has an aperture (if the G is, there is no diaphragm ring, and the aperture passes through the body turntable). 4) IF, which means the inner focus, focusing the front of the lens does not rotate, more suitable for the installation of polarizer, tapered mirror and so on. 5) if the final face is marked with ED, it means that it contains high-grade lenses. Two. Look at the quality of the lens, the key is to see the size of the aperture and whether it is constant. For example, the front of the lens, the aperture is 2.8-4, indicating that the maximum aperture is not constant, but the aperture is relatively large, so the lens price is not low. Some lenses have an aperture of 2.8, so the zoom lenses are more professional and expensive. The focus lens is the same. The bigger the aperture, the more expensive it is. Three. The rest is nothing more than the lens anti shake, materials and workmanship, caliber, size and so on. A camera lens (such as 85mm) and zoom lens (such as 28mm-200mm), is now common zoom lens. The quality of said lenss focal imaging from a professional point of view certainly is good but not easy. The lens is rarely useful in non professional. This is not to say m