A camera is simply a light-proof box with a lens at one end and light-sensitive material at the other. In a digital camera, this light-sensitive material is the camera’s image sensor. The amount of light that reaches the camera’s image sensor is known as exposure.
Three camera settings determine the exposure for a photograph: shutter speed, aperture and ISO. Each of these settings controls light differently. Explore the following resources in this collection to learn how combinations of these settings can achieve proper exposure.
Shutter Speed
The shutter is a mechanism that opens and closes to admit light into a camera for a measured length of time. Check out Controlling the Shutter Speed for Better Pictures to learn how shutter speeds affect exposure and effect stopping or blurring motions. Also, understand how shutter speeds affect the amount of light allowed to enter and for how long. Knowing how to control the shutter opens up a world of creative possibilities.
Aperture
The aperture is the opening created by a set of overlapping metal blades, known as the diaphragm, inside a photographic lens. Camera Aperture Demonstration explains how this opening controls the amount of light, or exposure, in the photo. In this resource, learn how aperture is measured in f-stops, which affects the depth of field. Awareness of how exposure and depth of field are the most important criteria for choosing the right aperture helps you better select the focus you need for your image.
ISO
ISO refers to the light sensitivity of the sensor in a digital camera. In a digital camera, you can adjust the camera's ISO setting to make the sensor more or less sensitive to light, depending on the situation. Discover the impacts of lower and higher ISO numbers on images in Understanding How ISO Matters for Proper Exposure. Familiarity with ISO numbers, ranges, and their implications will help you decide which settings you need for more or less exposure in your images.
Explore this collection of resources to review the basics of aperture, shutter speed and ISO settings to help you determine proper exposure.