When is aperture priority used? When is the shutter priority?

In the case of dim light, the shutter must be used first, which can ensure the film yield and will not ruin the shooting because of blur. In photography such as sports, the subject moves faster, and the shutter priority mode should also be used.

Aperture priority mode is generally used in portrait photography and artistic photography, mainly through the aperture size to adjust the prominence of the theme, and at the same time achieve a certain background blur requirements.