Basic Concepts in Photography

BASIC CONCEPTS IN PHOTOGRAPHY When you become comfortable with your camera, that is when photography becomes the most enjoyable. Building the right understanding of the core concepts in photography is a way to achieve that level of comfort. UNDERSTANDING EXPOSURE Exposure determines how light or dark an image appears when it has been captured by your camera. One of the essential parts of developing your intuition in photography is learning to control exposure. Exposing photography is similar to collecting rain in a bucket. Although the rate of rainfall is uncontrollable, three factors remain under your control: the size of the bucket, how long you leave the bucket in the rain, and the amount of rain that you need to collect. You wouldn’t want to collect too little— known as “underexposure” or too much— known as “overexposure”. EXPOSURE TRIANGLE Just as collecting rain in a bucket is controlled by the bucket size, its exposure, and the quantity of rain desired, collecting light for exposure is determined by three camera settings: aperture, shutter speed, and ISO speed. Together, these settings are known as the “exposure triangle”. Aperture The width of the opening that lets light into your camera lens is determined by a camera’s aperture setting. Cameras measure the aperture using the f-stop value. When the f-stop value decreases to allow light more in, the shutter speed has to be faster to compensate for the amount of light passing through the lens. When the f-stop value increases, the shutter speed has to be slower. A camera’s aperture setting affects the distance from the lens to where objects appear acceptably sharp, both in front of and behind where the camera is focusing. This range is commonly referred to as the “depth of field”, it’s an important creative tool in photography for isolating a subject from its surroundings by making the subject look sharper than its background. Lower f-stop values create a shallower depth of field— more separation between the subject and background, whereas higher f-stop values create a more expansive depth of field— less separation between the subject and background. Wide aperture, low f-stop value (f/2.0) for a shallow depth of field Narrow aperture, high f-stop value (f/16) for an expansive depth of field The range values of aperture vary from camera to camera or lens to lens. A compact camera might have an available range of f/2.8 to f/8.0, whereas a DSLR camera might have a range of f/1.4 to f/32 with a portrait lens. A greater aperture range gives you more creative flexibility, but a narrow range isn’t usually a big problem. Shutter Speed A camera’s shutter speed determines the duration of the camera’s sensor exposure to light. When the exposure time doubles, the amount of light entering the camera doubles. Shutter Speed 1 to 30+ seconds ½ to 2 seconds 1/30 to 1/2 second 1/250 to 1/50 second 1/500 to 1/250 second 1/8000 to 1/1000 second Typical Example To take specialty night and low-light photos To add a silky look to flowing water landscape photos on a tripod to enhance the depth of field To add motion blur to the background of the moving-subject, carefully taken, handheld photos with stabilization To take typical handheld photos without substantial zoom To freeze everyday sports/action, in moving-subject, handheld photos with substantial zoom (telephoto lens) To freeze extremely fast, up-close subject motion Slow shutter speed is useful for blurring motion, as when capturing waterfalls or when experimenting with creative shots. Fast shutter speed is useful for freezing motions, as when capturing a flash of lightning or capturing sports images that involve fast actions. Slow shutter speed (blurs motion) Fast shutter speed (freezes motion) ISO speed The sensitivity of the camera to incoming light is called the “ISO speed”. Similar to shutter speed, it also relates to how much the exposure increases or decreases. However, unlike aperture and shutter speed, a lower ISO speed is almost always desirable as a higher ISO speed also increases image noise or “grains.” Low ISO speed (Less image noise) High ISO speed (More image noise) Common ISO speed include values of 100, 200, 400, and 800. With DSLR cameras, a range of 100 to 3200 (or even higher) is often acceptable, whereas, in compact cameras, an ISO speed of 50 to 400 generally produces acceptably lower image noise.