How to adjust the aperture of camera lens? The smaller the focal length, the larger the aperture?

Adjusting the aperture should be set on the camera according to the scene light, and the aperture and shutter speed are a combination. The faster the speed, the larger the aperture (the smaller the value).

For example, in cloudy weather, the shutter speed of your camera is set to1125 seconds, so the aperture is F8. When you set the speed to 1/250 seconds, the aperture should be F5.6.

The numerical values of the aperture on the lens are 2.8, 4, 5.6, 8, 1 1, 16, 22. ......

The smaller the focal length, the greater the luminous flux of the lens, so the same exposure combination will appear brighter when using 18MM, and the exposure will be less when using 70 mm.