Compare the photos taken under different conditions and describe how to use the photographic light source correctly.

Generally speaking, light can be divided into three main types according to the irradiation direction, namely forward light, lateral light and backward light. Parallel light is light from the back of the camera. Because the light shines evenly on the subject from the front direction, the light receiving area of the subject is large and there are few shadows. It is relatively easy to measure light and control exposure when shooting. Even if the camera's automatic exposure system is used, there will generally be no exposure errors. In the case of smooth light, no matter whether the surface of the subject is uneven or not, due to the same light receiving situation, shadows are not easy to appear, which will lead to the lack of texture and three-dimensional sense of the subject, and the description of the subject tends to be dull; Side light refers to the light emitted from the side of the subject, which can make the concave and convex on the surface of the subject show a clear shadow, and the texture is an ideal light for the texture of the subject on the surface. Side light can not only outline the outline of the subject, but also reflect the three-dimensional sense, which is a common light in photography. Backlight refers to the light that the sun shines from the back of the subject. It is conceivable that in the case of backlight, the subject often becomes a silhouette, so it is relatively difficult to grasp the exposure. Backlight can set a striking and touching Phnom Penh on the outline of the subject. If handled properly, it can create a unique aesthetic feeling and shoot a sense of light and shadow full of dramatic effects. When taking backlight photos, if you measure the light according to the background or expose it according to the automatic program, you will often be underexposed. Be sure to pay attention to exposure compensation or fill light, which can be synchronized by reflector or flash during the day.