What are the three elements of exposure?

Aperture, shutter and sensitivity form the "exposure triangle". The following figure shows the relationship between them and their principle of action on exposure. One of them increases one file, the other decreases one file, and the exposure remains unchanged. Therefore, on the basis of determining the accurate exposure, the three can be adjusted and changed according to their own needs (such as automatic metering with a camera).

The shutter controls the exposure time. The higher the shutter value, the shorter the exposure time and the darker the picture, and vice versa. Aperture controls the size of the lens entrance aperture. The larger the aperture value, the smaller the actual aperture and the darker the picture, and vice versa. Sensitivity controls the sensitivity of the sensor to light. The larger the ISO value, the more sensitive the sensor is to light and the brighter the picture, and vice versa.

Extended data:

For example, if you want to take a portrait with a blurred background in broad daylight, you need a large aperture for the blurred background, but the large aperture will improve the brightness, especially on sunny days, and the picture will be overexposed. At this time, you should consider increasing the shutter speed to reduce the brightness until the brightness is normal.

If you use a low-end camera (the highest shutter of the low-end camera is 1/4000 seconds) and it is still overexposed at 1/4000 seconds under sunlight, you need to put a dimming filter or a medium gray filter in front of the camera.