2023年9月18日 · Without getting into an in-depth physics discussion, the focal length of a lens is an optical property of the lens. The exact definition is: Focal length measures the distance, in millimeters, between the “nodal point” of the lens and the camera’s sensor. “Nodal point” may sound complicated, but it is simply the point where light ...

For a thin lens in air, the focal length is the distance from the center of the lens to the principal foci (or focal points) of the lens. For a converging lens (for example a convex lens), the focal length is positive and is the distance at which a beam of collimated light will be focused to a single spot.

As such, a lens’s focal length is the first number you will read in the names of most lenses on the market. But what exactly is focal length, how is it calculated, and which focal lengths are best suited to which applications? In this article, we aim to answer all these questions with a complete guide to focal length. What Is Focal Length?

The principal focal length of a lens is determined by the index of refraction of the glass, the radii of curvature of the surfaces, and the medium in which the lens resides. It can be calculated from the lens-maker's formula for thin lenses.

2024年2月2日 · The focal length of a lens is the optical distance from the point where the light meets inside the lens to the camera’s sensor. What difference does this make? Read on

2024年1月11日 · Ultra-wide angle and fisheye lenses can have focal lengths as short as 8mm. As the name suggests, they possess an ultra-wide field of view, creating an almost panoramic effect, making them useful for extreme landscapes, events and creative photography. Their distortion makes them less than ideal for portraiture.

2024年2月27日 · The focal length of a lens determines the angle of view, with shorter focal lengths capturing a wider angle and longer focal lengths capturing a narrower angle. What types of lenses have different focal lengths?

2023年2月7日 · The focal length of a lens will determine not only how much of a scene you will be able to capture at certain distances, but also how the objects in the scene will appear on the camera’s...

This lesson emphasizes the role of lenses in shaping a photograph, particularly through focal length, depth of field, and focus distance. It explains lens components, their function in focusing light, and key markings like focal length, aperture, and …

Focal length is the distance from the center of a lens to its focal point, where parallel light rays converge or appear to diverge. It determines the converging or diverging power of the lens.