How about photography? How about taking a waterfall?

Use a or m, and use the smallest aperture, such as F22. This effect can be achieved by keeping the shutter between 1/4~4S. The specific value depends on the actual environment. If necessary, use a medium gray mirror.

If you use the shutter first, it depends on whether your aperture can meet the environment at that time. I estimate that when you set it to 1s, the film should be all white, which means it is overexposed. The use of M file depends on the metering data, and the aperture and shutter can't be set casually.

In addition, you must use a tripod to take this photo (as long as you can fix the camera).