What does focal length determine in photography?

Focal length in photography is a critical factor that influences the size and magnification of the image captured. It is defined as the distance in millimeters between the lens and the image sensor when the subject is in focus. A longer focal length increases the magnification of the subject, allowing makers to capture distant objects more clearly, rendering them larger in the photograph. Conversely, a shorter focal length results in a wider field of view, which can create a smaller representation of the subject within the frame.

This relationship between focal length and image size is essential for photographers to understand, as it directly impacts composition, perspective, and the overall feel of the photograph. While factors such as snap speed, color saturation, and image clarity are relevant in photography, they do not specifically relate to the function of focal length.