Most digital cameras come with exposure modes on them. The camera uses this tool to set the proper exposure for your photo. There are different modes on the camera and while they act a little differently they all have the same objective.
If you select auto or program mode the camera will choose both the shutter speed and aperture automatically for the lighting conditions. All you need to do is take the photo and not worry about anything. However, it’s not always going to give you the best results.
The AV setting is for aperture priority. This is basically half manual and half automatic. You can choose the f stop you want to shoot at and the camera will use a meter reading and match up the f stop with the appropriate shutter speed. This setting lets you control the image’s depth of field. Just make sure the camera isn’t using a shutter speed that’s too slow for the subject.
If you use the camera’s manual mode, it will allow you to set the aperture, shutter speed, and ISO. However, you’ll need to practice with this mode so you know which settings you want to use to get the desired effects for your photos.