Ask the photographer to come over.

Among them, the first and third photos were taken against the light. In the first photo, the background is the grass behind, which makes the sky overexposed, and then the reflector (or flash) is used to fill the main body with light, and the large aperture blurs the background; The third exposure takes the sky as the background, which makes the sky appear beautiful blue and clouds. It also fills the model with light, but the intensity is higher than the first one, and uses a small aperture below F 1 1 to make the sun form a star. In addition, the third picture also uses a wide-angle lens and is shot at a slightly upward angle. The exaggerated perspective effect gives people a strong visual impact and makes the model's legs look longer.

The second picture uses the side backlight and the front reflector to fill the light, which is slightly overexposed, making the model's skin look very white, reducing the contrast and saturation, so-called small and fresh style.

In a word, these photos are all successful outdoor portrait works with backlight. The general function of backlight is as silhouette light to simplify the background. You will find that there is a circle of light on the edge of the character's hair, and the background of backlight is often overexposed white, which can highlight the character and create an atmosphere. Side backlight can also enhance the luster of hair. The first two pictures highlight the main body with a large aperture, blurring the background, and the third picture is the opposite. Small aperture and large depth of field reflect the environment well and have the feeling of atmosphere.

Of course, it is almost impossible for the original film to think of this effect directly, and it needs post-processing, which is also an important part of photography.

I hope my answer will satisfy you.