Why are 3d lights always exposed?

You can change the exposure mode to logarithmic exposure. When lighting, first hit the main light source, and then block the grass to observe the brightness, pay attention to the lighting range. At this time, the whole environment should be dark, and then some parts should be adjusted by supplementing light. This lamp should be very small. Generally speaking, it is necessary to constantly observe and adjust the lighting. I want to hit these kinds of lights in a scene, ambient light+sunlight+main light+auxiliary light+.