Photography Note 66- What does the speed of the camera lens mean?

The maximum aperture of the photographic lens determines the shutter speed, so the photographic lens is also divided into fast and slow.

Lens speed refers to the amount of light that the lens can transmit in a certain period of time. A lens with more transmitted light is called a fast lens, and a lens with less transmitted light is called a slow lens. It is judged that snapshot and slow snapshot are relative, and there is no clear shutter speed limit. For example, in a low light environment, the shutter speed of 18-55mmF3.5-5.6 is 1/8 seconds when shooting at the maximum aperture, while the shutter speed of 50mmF 1.4 is 125/ second when shooting at the maximum aperture. At this time, the shutter speed of the latter is faster than that of the former, and the latter is called fast lens.