How to control the depth of field of SLR camera

If the camera can shrink the diaphragm blade before the shutter curtain is opened (when the film is unexposed), the depth can be previewed from the viewfinder window. Single-lens reflex camera is in full aperture, that is, the maximum aperture state. After pressing the preview button of depth of field, the aperture is reduced to the set value, so as to watch the effect.

For example, Xiaobai: EF 70-200mm2.8, with a maximum aperture of 2.8. Now set it to f 1 1 to shoot. Before pressing the shutter, the aperture is f2.8, which is convenient for focusing. When the shutter is pressed, the aperture is reduced to the set value of f 1 1 for shooting. If the preview of depth of field is pressed when shooting, the aperture will be reduced to f 1 1 to shoot.

Extended data

The larger the aperture, the smaller the depth of field, and the smaller the aperture, the greater the depth of field. The longer the focal length of the lens, the smaller the depth of field, and vice versa. The closer the subject is, the smaller the depth of field is, and the farther the subject is, the greater the depth of field is.

When the lens of a camera is clearly focused on an object, the point on the same plane perpendicular to the lens axis at the position opposite to the lens center can form a quite clear image on the film or receiver, and the point in a certain range before and after the lens axis can also form a relatively clear image point acceptable to the eyes. The distance between all the scenes before and after this plane is the depth of field of the camera.

Baidu encyclopedia-preview of depth of field

Baidu encyclopedia-depth of field