Exposure Techniques
Posted on August 15, 2009
Filed Under Digital Camera Features, Good Digital Cameras |
Lighting plays the major role in the photographing process. This is because bad lighting will obscure the photo’s subjects and composition, leaving little to be appreciated. Good lighting, on the other hand, defines the form of your subjects and show them in vivid colors. Learning how to capture the correct amount of light is an essential part of photography.
During the capture of a single photograph, the photographic medium (film or digital sensor) is allowed to gather a certain amount of light indicated by its exposure. There is no fixed value of a correct amount of light, because it depends on the available lights, the objects, and the photographer’s judgment. But there is a range of accepted exposures that, while produce different results, cannot be seen as mistakes. Unaccepted exposures are, in general, due to a mistake rather than a photographer’s intention.
Basically, a dark scene will need long exposures, allowing more light to be collected by the sensor, which translates to a well exposed photograph. Otherwise, the photograph will be underexposed, having too many dark areas, the dark objects loosing their details, and the bright objects becoming dull. As for bright light conditions, low exposure will be enough to gather sufficient amount of light to produce a photo with good lighting. Otherwise, the photograph will be overexposed, having too many bright areas, the bright subjects loosing their details, and the dark subjects looking too bright..
The camera controls the exposure through shutter speed and aperture. Shutter speed controls the time for which the shutter will stay open. The faster the shutter speed is, the less light will get to the sensor. As for aperture, it determines how wide the lens is opened. Logically, a wide aperture is used to get more exposure, while a narrow one is used for less exposure. Another component that affects exposure is the ISO speed, which indicates the light sensitivity of the sensor. Higher ISO speeds will make the sensor more sensitive to light, reducing exposure, but it will add undesired noise to the photos.
In manual exposure mode, aperture and shutter speed are usually set independently. As for automatic exposure settings, the camera will determine the degree of exposure needed according to the light metering technique used. Because of the lack of manual controls over exposure in many low-end cameras (including most digital compact cameras), exposure compensation (if available) should be used to fine tune the automatic exposure suggested.
Photographs with very dark and very bright spots will not show correct exposure on all their parts using any type of cameras. Usually, photographers take the same photograph at different exposures, and combine them together using software programs.
A good approach to learn more about exposure is to look at the exposure settings of your previous photographs, and compare them Look especially at photographs that you feel are not well exposed, and try to figure out what went wrong. This is the best way to understand these things practically.
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