The difference between the length of the camera lens

When referring to the "length" of a camera lens, there are two aspects to consider: the physical length of the lens and the focal length.

1. Physical Length:

The physical length of a camera lens refers to its actual size and dimensions. It is the measurement from the lens mount to the outermost point of the lens barrel when the lens is at its minimum or retracted position. The physical length can vary significantly between different lenses, even with similar focal lengths.

Physical lens length is important to consider for factors such as portability, balance on the camera body, and fitting into camera bags or cases. Longer telephoto lenses, for example, tend to be larger and heavier due to the design required to achieve their longer focal lengths.

2. Focal Length:

The focal length of a lens is a crucial parameter that determines the lens's field of view and magnification. It is the distance between the lens's optical center and the camera's im

age sensor or film plane when the lens is focused at infinity. Focal length is typically measured in millimeters (mm).

Shorter focal lengths, such as 24mm or 35mm, are considered wide-angle lenses, providing a wide field of view. Longer focal lengths, such as 50mm, 85mm, or 200mm, are considered telephoto lenses and offer a narrower field of view with magnification.

The choice of focal length affects how much of the scene is captured within the frame, the perspective and distortion of the image, and the magnification of the subject.

It's important to note that the physical length of a lens and its focal length are not directly related. Two lenses with the same focal length can have different physical lengths due to variations in their internal lens design and construction.

When selecting a lens, it is recommended to consider both the physical length for practical purposes and the focal length for the desired field of view and magnification.