In part 1 of: Get the most out of your camera, we looked at how to use the aperture and the creative uses of depth-of-field. In this part we'll look at how to use the shutter button on your camera and how both the shutter and the aperture control exposure.
The shutter is a mechanical device that controls the length of time that light is allowed to act on the film.
Most standard cameras allow us to use a range between 16 second and 1/1000 second. You might be wondering, why anyone would use a long shutter time of 16 seconds: I've used this and even longer shutter times when taken lowlight landscape images. I would always advise the use of a tripod with these long exposures time to avoid blur images.
Using a shutter speed of 1/125 second should safely avoid overall blur due to camera movement if you hold the camera by hand. Any longer shutter time should require a tripod.
Each time you open the shutter by one, we double the light, when we close down the light by one we half the light. Open the shutter at 1 second allows twice the light as that of a ½ second.
The shutter can also be used creatively when taking landscape images or sport images. If you want to add motion to your image a slow shutter speed can give an image an extra bit of sway. No more so than taking images of streams. Using a slow shutter speed when photographing water will cause the water to blur, resulting with the image expressing motion.
By contrast, a fast shutter speed of 1/250 would be used in shooting wildlife or where the subject that you're shooting needs to be still and sharp. Most wildlife photographers would use a fast shutter speed.
By using the shutter and aperture together we control exposure. Both allow light to enter the camera: the shutter by time and the aperture by the size of the hole in the lens.
For example: you're shooting a landscape scene; you get an exposure reading at f/11 at ¼ second. You know that by using f/11 that the entire image wont be sharp. You want to shoot at f/22, which is four times less light than f/11. You need to quadruple the light through time; each time you open the shutter by one you double the light, so open it by two stops and your exposure time will be 1 second. Your final exposure should read f/22 at 1 second.
At the best of times, calculating the correct exposure can be a difficult task, but with a few simple tips our images can produce eye-catching colours that we see all around us every day.
TJ Tierney, Irish Landscape photographer. http://www.goldprints.com
