Avoid using aperture to compensate for poor lighting

Changing the aperture has a dramatic effect on the amount of light coming into the camera, as we have already said. You'll notice this is the case when shooting landscapes with a narrower aperture (higher numbered f-stop) as your camera will often want to take a longer exposure -- so much so that you may have to use a tripod to avoid motion blur.

You should avoid using the aperture scale to compensate for unfavourable lighting, however, as it also changes the amount of the image that remains in focus, as we'll explain below.The image on the left was taken with a wide aperture and so has a shallow depth of field; the image on the right was taken with a narrow aperture and so has a long depth of field.