Focal length refers to the distance between the lens of a camera or telescope and the image sensor or film when the subject is in focus.
Focal length is measured in millimeters (mm) and is determined by the curvature of the lens and the distance between the lens and the sensor or film.
The focal length of a lens determines the field of view, or how much of the scene can be captured in the image. A shorter focal length results in a wider field of view, while a longer focal length results in a narrower field of view.
No, the focal length varies among different lenses. Prime lenses have a fixed focal length, while zoom lenses have a range of focal lengths that can be adjusted.
Focal length plays a crucial role in photography and optics as it affects the perspective, depth of field, and composition of an image. It also determines the magnification and clarity of the subject being captured.