焦距
How to Understand
Focal length refers to the distance between the optical center of a lens and the image sensor when the subject is in focus. It is a fundamental concept in optics, particularly in photography and cinematography, determining the magnification and angle of view of a lens.
The character 焦 (jiāo) originally meant 'to roast' or 'to burn,' but in this context, it relates to the point of focus. 距 (jù) means 'distance' or 'interval.' Together, they form a term that precisely describes the optical distance in lenses.
In practical use, focal length determines how a camera captures a scene—shorter lengths offer wider angles, while longer lengths provide zoomed-in views. Understanding focal length is essential for photographers and filmmakers to control visual storytelling effectively.