The necessity of photography photometry?

Photometry is absolutely necessary. Don't take a nap without photometry.

The film machine has to see the exposure meter. It is said that photographers used to recite that watch.

SLR cameras are equipped with exposure meters. Generally, there is a ruler-like thing in the middle of the viewfinder with a small mark on it.

Improper metering will lead to overexposure and underexposure, that is, photos are too bright and too dark, which can be saved later, but it will lead to noise and other problems.

Accurate focus, correct exposure, reasonable composition, no one can be less.