What does backlighting refer to in photography?

Backlighting in photography refers to the illumination that comes from the opposite side of the camera, creating a distinctive visual effect. When a light source, such as the sun, is placed behind the subject, it often results in the subject appearing darker while the background is illuminated. This technique can create a dramatic outline or halo effect around the subject, emphasizing its shape or form. It is commonly used to convey a sense of mystery or to enhance a subject's presence within an image.

The other options describe different lighting conditions or uses but do not accurately define backlighting. Direct light on the camera or lighting that highlights the lens does not capture the essence of backlighting, which relies specifically on the light source's position relative to the subject and the camera. Similarly, the use of flashes to enhance shadow details focuses on different lighting techniques that do not involve the direct opposite positioning crucial to backlighting.