I want to learn the use of flash recently. When should I use a soft mask and a reflective film? Are there differences or similarities between the two?

It may be wrong, but it's all my own experience.

There is a big difference between the two. The role of the reflector can be understood as a spotlight source, which makes the light that originally hit the top or failed to hit the subject focus on the subject area, but the overall light source is still relatively hard, and the effect is not obvious when the shooting distance is far away. One is to make the light source softer, and the other is to make the area of the light source larger. For example, patting a bottle often leaves a reflective flash on the bottle. Using a large area of soft light mask and then leaning against the subject can reduce this situation. Attached pictures can help you understand better. The one on the left is a 32-inch soft mask, and the one on the right is a wooden belt soft mask. Use a transparent storage box about half the size of A4 paper, pad a layer of white paper at the bottom, and then flash in the box. . . —? —! )。 The function of soft mask can be clearly seen through the light spots in the bright parts of both.