We have a question and answer about photography. May I ask a few questions? Shallow.

Controlling the depth of field of a photo is a very important photography technique. The so-called depth of field is the clear range before and after the focus. The greater the depth of field, the clearer the whole image will be from the distant view to the close view. The shallower the depth of field, the clearer the focus subject will be, and the more blurred the foreground and background will be, thus highlighting the subject more. The main factors affecting the depth of field are focal length, aperture and shooting distance. The longer the focal length, the larger the aperture, the closer the shooting distance and the shallower the depth of field; Conversely, the shorter the focal length, the smaller the aperture, the farther the shooting distance and the greater the depth of field.

Through this passage, we can ask several questions: What is the depth of field? What are the factors affecting the depth of field?

If the focal length is higher than 70mm, the telescopic effect is supported. If it is less than 28mm, it means that it has wide-angle shooting ability, and the 50mm lens is closest to the natural perspective of the human eye.

Through this sentence, we can ask: how long is the focal length below mm, and we say that he supports wide angle? 28 mm

What is the focal length above mm? We said he supported the telescope effect. 70 mm

What is the focal length of the lens closest to the natural viewing angle of the human eye? 50 mm