What does 35mm equivalent focal length mean?

The equivalent 35mm focal length means that the angle of view of the photos taken by this lens is equivalent to that of a 135mm camera with a 35mm lens. Due to the different sizes of photosensitive elements, the focal length of the lens of an ordinary digital camera usually needs to be converted into a value equivalent to that of a 135 film camera.

On a camera that uses 35mm film, the 28mm lens is a wide-angle lens, and the 200mm lens is a telephoto lens. However, now that digital cameras have almost completely replaced 35mm film cameras, there is no longer a uniform relationship between focal length and angle of view. Because the sensor size of the camera also affects the angle of view, and the size of the sensor is no longer as unique as it was in the film era. For a specific lens and sensor combination, a 35mm equivalent focal length means that this focal length can produce the same angle of view on a 35mm film camera.