An 80mm focal length refers to the distance from the lens to the image sensor when the lens is focused at infinity. This measurement is crucial in photography as it influences the perspective and composition of an image. Lenses with an 80mm focal length are often categorized as short telephoto lenses, making them ideal for portraits and close-up shots. Using an 80mm lens, such as a Canon EF 80mm f/1.2L, allows photographers to achieve a pleasing background blur, known as bokeh, while keeping the subject in sharp focus. This focal length provides a natural perspective, making it popular for capturing details without distortion.