Understanding Exposure: Special Situations
By Jonathan Hanson
A photograph is created by light; capturing exactly the right amount of light is what constitutes proper exposure. There are three aspects to exposure, and you've already been introduced to one of them: film speed. Shutter speed is the amount of time the shutter is open to let the fight through the lens aperture and onto the film. Because film speed is set once you put the roll in the camera, the only variables you have to worry about while taking photographs are shutter speed and aperture.
Moving water: The movement of flowing water will be completely stopped at 1/2000 second. At 1/60, the faster portions of the stream will begin to blur. Shutter speeds from 1/8 second to several seconds will produce a soft, ethereal quality.
Fireworks: To capture nighttime fireworks using ISO 100 film, set your aperture at f/8 or f/l1 and the focus at infinity. With the camera on a tripod, set the shutter on B and hold it open for several seconds (with a cable release) while fireworks are going off.
Moon: For a full moon on a clear night, using ISO 100 film, expose at f/8 for 1/250 second. Increase the exposure one stop if there are clouds or haze. For a half-moon increase the exposure one stop; two stops for a quarter moon.
Aurora borealis: With ISO 100 film and the camera on a tripod, expose for 8 to 30 seconds with the lens wide open (f/1.4 to f/2.8).
Lightning: Select a location away from bright lights. Use a normal or medium wide-angle lens set at f/8 or f/ll with the camera on a tripod and the shutter set on B. Open the shutter, wait for a lightning strike or two, then close the shutter.
Sunrises and sunsets: Slight underexposure will increase color saturation and produce a richer, more dramatic image. A common exposure error when shooting sunrises and sunsets is gross underexposure caused by the brightness of the sun. To avoid this, select and meter the portion of the sky to one side of the sun that you want to reproduce as middle-toned. Then recompose the picture using that setting.
Rainbows: To increase color saturation, underexpose 1 to 1 1/2 stops depending on the darkness of the background sky (the darker the sky, the more you underexpose).
Water, snow, or bright sand: The high reflectance of light-colored surroundings will cause your meter to give an underexposed reading of a darker main subject. To correct this, either spot-meter the subject, substitute meter a middle-toned object, or increase by 1 to 2 stops an averaged metering.
Flames: With ISO 100 film set the shutter to 1/60 and the aperture to f/2.
Subjects illuminated by flames: With ISO 100 set the shutter to 1/8 and the aperture to f/2.
Fog: In dense fog with no sun, increase exposure 1 1/2 to 2 stops over your meter reading. In fog with visible sun increase by 1/2 to 1 stop.
Dark-skinned faces: Spot-meter the face if you can, then decrease exposure by one stop. With an averaged reading and a lighter background increase by 1 stop.
Birds in flight: The bright background of the sky will overwhelm the meter, resulting in an underexposed main subject. Take a reading off a substitute middle-toned subject in light shade (since the underside of the bird above you will be shaded) or open up an averaged reading 1 1/2 to 2 stops.
Excerpted from Basic Essentials Photography In The Outdoors, 2nd Edition by Jonathan Hanson with permission from Falcon Publishing.
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