Do you know the basic knowledge that you must know to learn SLR-exposure compensation and the principle of "white plus black minus"?

Today, with the advanced metering system, exposure errors still exist widely. In manual exposure, the aperture shutter can be set separately, and exposure compensation is needed to control the error of aperture priority and shutter priority.

1. exposure compensation

Exposure compensation is an exposure control method, which is often used in? 2-3EV, if the ambient light source is dark, you can increase the exposure value (such as+1EV, +2EV) to highlight the clarity of the picture. Exposure compensation is automatically calculated by consciously changing cameras? Is it suitable? Exposure parameters, a shooting technique that makes photos brighter or darker. Photographers can adjust the brightness of photos according to their own ideas to create unique visual effects. Generally speaking, the camera will change the aperture value or shutter speed to adjust the exposure value.

Exposure compensation

2. Method of use

When actually operating aperture priority, the aperture value has been set and the camera will give the shutter value. At this time, the exposure compensation is adjusted, the aperture value remains unchanged, and the shutter value will change accordingly according to the compensation amount. For example, if the aperture is set to 5.6, the speed given by the camera is 1/250 seconds, and the exposure compensation is+1, the speed becomes1125 seconds. Similarly, in the case of shutter priority, if the shutter is set to 1/30 seconds and the aperture is given by the camera as F8, then the exposure compensation is -2, the shutter value remains unchanged and the aperture is reduced to F 16.

Exposure compensation difference

3. Application

When the shooting environment is dark and it is necessary to increase the brightness, and the flash can't work, exposure compensation can be carried out to increase the exposure appropriately. When the photographed white object looks gray or not white enough in the photo, increase the exposure. When the black object being photographed looks gray or not black enough in the photo, reduce the exposure. 4.？ White plus black minus? principle

White plus black minus? It is to increase the exposure when shooting the overall bright (white) scene and reduce the exposure when shooting the overall dark (black) scene.

White plus principle

According to the principle of photometry mentioned above, in real life, all kinds of objects have their own colors, such as coal is black and snow is white. When the camera is aimed at black coal, the camera can't tell whether the black is caused by dim light or whether the object itself is black. Then even in the daytime, the camera will think that this black is much lower than the brightness of 18 degree gray and increase the exposure, so the coal will be shot gray at last. By the same token, when shooting snow, the camera will mistakenly think that the light is very strong, so it will reduce the exposure and shoot the snow gray.

Blackout principle

Because of the different reflectivity of various scenes, there is no specific standard for compensation range, so photographers should form the habit of carefully observing scenes, analyze the balance and reflectivity between black, white and gray, grasp the exposure essentials they need from thinking and practice, and shoot wonderful works.