In photography, what is a shake card? What are the specific photography techniques and how to do them? I am just getting started with photography and would like some advice from an expert. Thank yo

In photography, what is a shake card? What are the specific photography techniques and how to do them? I am just getting started with photography and would like some advice from an expert. Thank you~

Card shake refers to using a dark card to partially block light in front of the lens to achieve balanced exposure. It is generally used to shoot scenes with strong contrast between the sky and the ground during sunset and sunrise. For example, the ground needs to be exposed for 5 seconds, the sky needs 2 seconds, and the sky is covered with a card for 3 seconds. Within 3 seconds, you must keep shaking the card.