High magnification zoom lens is very convenient. Why do photographers prefer low magnification zoom lens and fixed focus lens

This section is selected from the column. There are 50 sections in the column. There are 49 wonderful sections waiting for you. Pay more attention and click “happy and carefree photography” to get more content. < / P > < p > many people do not have a good understanding of the concept of focal length, even think it is the length of the lens. About the concept of focal length theory, middle school textbooks have, here not much to say, we talk about the focus from the real sense. < / P > < p > no matter what kind of camera lens has focal length, but we haven’t studied the non interchangeable lens camera. For example, what is the focal length of your mobile phone camera? I don’t think most people know. But people who are more careful about these parameters will know. For example, for Huawei P40, the focal length of the rear camera is: the focal length of the 50 megapixel main camera is 23mm, that of the 40 megapixel ultra wide angle camera is 18mm, and that of the 12 megapixel long focus camera is 125mm. < / P > < p > for the interchangeable lens camera, the lens focal length is a very important parameter, most people know. However, for beginners who have not used different focal length lenses, they may not understand the concept of focal length. < / P > < p > we can better understand the focal length from the characteristics of focal length: the smaller the focal length, the wider the viewing angle when shooting, that is, the larger the shooting range, the smaller the proportion of a specific object in the picture; the larger the focal length, the smaller the shooting angle, that is, the smaller the shooting range, the larger the proportion of a specific object in the picture. However, the focal length of a lens is not infinitely small and infinite. For example, the focal length of a full frame lens is generally as small as 14mm and as large as 800mm. Smaller or larger focal length can be considered as special lenses. < / P > < p > we use a tripod to fix the camera, and take pictures with different focal lengths in the same position to see the difference visually. As shown in the above figure, we take pictures with 18, 26, 35, 50, 70, and 100 mm focal lengths respectively. It is obvious that with the increase of focal length, the shooting range becomes smaller and the proportion of that high-rise building in the picture increases. < / P > < p > in addition to the above features, what are the features of focal length? Generally speaking, the picture with small focal length has a larger depth of field, while the focal length becomes larger and the depth of field becomes smaller. Therefore, the wide-angle focal length is generally used for the large depth of field scenery photos, while the long focal length is generally used for the photos that need to be blurred. This point can also be seen in Figure 2. When the focal length is small, the wicker in the picture is clear. When the focal length reaches 70mm, the wicker is very fuzzy. Taking advantage of the focal length of the lens, we often use long focus or ultra long focus lens to take photos that need to be virtual background, such as flower close-up. New product launch