The premise of shooting fixed the picture is that the plane position, optical axis and () remain unchanged.

The premise of shooting fixed the picture is that the plane position, optical axis and focal length remain unchanged.

Focal length, also known as focal length, is a measure of light convergence or divergence in an optical system, which refers to the distance from the center of the lens to the focal point of light convergence. That is, the distance from the optical center of the lens to the imaging plane such as the backplane, CCD or CMOS in the camera. An optical system with a short focal length has a better ability to collect light than an optical system with a long focal length.

The lens of a camera is a set of lenses. When the light parallel to the main optical axis passes through the lens, the light converges to a point called the focal point, and the distance from the focal point to the center of the lens (that is, the optical center) is called the focal length. A lens with a fixed focal length, that is, a fixed focus lens; The lens whose focal length can be adjusted and changed is a zoom lens.

A convex lens can image. Generally, when a convex lens is used as the lens of a camera, the clearest image formed by it will not fall on the focus, or the distance from the clearest image to the optical center is generally not equal to the focal length, but slightly larger than the focal length. The specific distance is related to the distance between the subject and the lens (object distance). The greater the object distance, the smaller the image distance.

The concept and skills of shooting;

Shooting is to record images of people and things with cameras and video recorders. Different scenes have different shooting techniques, including night scene shooting, rain scene shooting, building shooting, portrait shooting and so on. Film dynamic art shooting is also a kind of shooting, but it must follow certain principles.

Shooting night scenes mainly refers to the scenery under outdoor lighting or natural light at night. When shooting, lights, firelight, moonlight, neon lights and shuttle cars on the street are the main light sources. When shooting, we must first keep the atmosphere at night and the authenticity of the lighting. We should use tripods, cable release and other accessories, and use one or more exposure forms.

When shooting a rain scene, it is generally necessary to use a larger aperture and a slower shutter speed to make the rain scene have enough sensitivity. In order to show the rain bars that have not yet landed in the scene space and master the dynamics in the rain, we should shoot at a higher position. Shooting a scene in light rain, because there is not enough light rain in the scene, it is impossible to show rain stripes.

When shooting the sunrise, you should shoot it as soon as the sun rises above the horizon. You can't miss it. Shooting the sunset can start when there is no light scattering, and it can only be taken with confidence when it is about to enter the horizon.