Aperture is the opening in your lens and controls how much light gets through to the camera’s sensor as well as the depth of field. Depth of field refers to the area surrounding the focal point of the image which remains sharp. A wider aperture (indicated by a lower f-number) lets more light through, but has a narrow depth of field. While a narrow aperture (indicated by a higher f-number) lets less light through, but has a wider depth of field. A wide aperture is great when you want to isolate your subject, but when you want the whole scene to be in focus, such as with group shots, you’ll need to use a narrow aperture.
Shutter speed controls how long the shutter stays open when you take a picture. The longer the shutter stays open, the more light gets through to the camera’s sensor. A fast shutter speed is good for freezing action, while a longer shutter speed will blur motion. Long shutter speeds can give interesting effects, but usually require a tripod.
4. Wide aperture is best for portraits
When shooting portraits, whether of people or animals, your subject should be the main focus of the picture and the best way to achieve this is to use a wider aperture. This will keep your subject sharp, while blurring out any distractions in the background.
Keep in mind that a smaller f/ number means a wider aperture and the wider the aperture, the more dramatic this effect will be. Some lenses can go as low as f/1.2, but even apertures of f/5.6 can do the trick. To better understand how the aperture affects your images, switch to Aperture Priority Mode (Av or A) and try taking some shots with different apertures.