Editors Note: Apertures and Shutter Speeds | From Lastolite School of Photography was originally written by Mark Cleghorn for www.lastoliteschoolofphotography.com and has been reproduced with permission.
Apertures and Shutter Speeds
The two main creative skills to learn with a camera are which aperture and which shutter speed settings to use when shooting different subjects. These two technical elements in photography help to not only gain a correct exposure when used correctly but will also move your creative photography to the next level.
The aperture controls the amount of light passing through the lens and hitting the cameras sensor. So the bigger the aperture in size the more light can pour through the lens, just like the Iris in the human eye lets more or less light through the pupil.
Like the human eye the aperture is usually wider in darker conditions and smaller in brighter conditions controlling the light passing through the lens. But unlike the eye the aperture also helps control the amount of depth of focus in the image.
An aperture equals an F-stop number and the bigger the number the smaller the aperture, which gives more of the image in focus. So what follows is the smaller the number the bigger the aperture the less that is in focus, Simple?
The shutter speed refers to the amount of time the shutter is left open to gain a correct exposure, it also controls the amount of motion freeze in an image or how much motion blur occurs with moving objects in the photograph. In a dark area the shutter speed will need to be left open longer to gain correct exposure depending on the aperture and ISO setting, this will cause any movement to be blurry.
The shutter speed can also be used creatively with flash. A slow shutter speed and flash combo is often referred to as ‘dragging the shutter’. You will usually need a tripod to support the camera for this technique; this is to keep image blur from the camera shake to a minimum.