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Using small apertures
Techniques
24 October 2007 09:53
Setting a small aperture reduces the amount of light reaching the camera’s sensor. This is useful in very bright conditions or when the camera’s on a tripod and you want to use a slow shutter speed for creative movement effects.
To convey the sense of movement at a sports event, use a small aperture and a slow shutter speed combination to pan with the action. This involves following the movement with your camera during the exposure. In bright conditions you’ll need to set a very small aperture to allow you to get these shutter speeds, so experiment with different settings to get the desired effect. In this shot, setting f/16 on the camera gave a 1/125sec shutter speed that’s perfect for shooting fast-moving subjects such as motor racing.
During the brightest parts of the day the light levels can be so high that you’re forced to use a small aperture. This can be a problem in bright, sunny locations though is rarely a big problem in the UK. To capture this sand dune we needed to use an aperture of f/16 to prevent overexposure.
Blurring the movement of subjects such as water, grasses or people can add extra atmosphere to your landscape and urban shots. To achieve the very slow shutter speeds required you’ll need to set the smallest aperture. Remember that you’ll need to fix the camera to a tripod to keep the rest of the scene sharp, and by using a small aperture most of the scene will be sharp due to the great depth-of-field.
Shooting early in the day at f/22 helped achieve a 1-second shutter speed for this shot of the reeds against the sky. This allowed the movement of the reeds blowing in the breeze to become blurred during the exposure. In brighter conditions you may need to set a smaller aperture and use a polariser or neutral density filter to reduce available light levels even more.