Monday, March 4, 2013
Understanding Aperture Priority
Don't just “take a picture,” “make a picture.”
Don't just "take a picture," "make a picture." Take charge of the settings on your camera so the image turns out the way you want. Don't let the camera make the decision. While the PROGRAM mode provides a perfect exposure ninety eight percent of the time, it doesn't know that in situation A it's important that the depth of field is shallow so your subject stands out from the background. It's also obvious that in situation B, it's more important that the depth of field extends from the most foreground part of the composition and goes out to infinity. While the computers in today's cameras are amazing and let you capture a great image, the manufacturers still haven't figured out how to interface PROGRAM mode with your brain so the final image turns out the way you want. This being the case, it's time to take charge of your settings to wind up with an end result of what you envisioned when you pressed the shutter. This week's Tip focuses on Aperture Priority mode. Another will focus on Shutter Priority.
The amount of depth of field that can be achieved is dependent upon a number of variables that fall into place. When the lens is set to f/16 or f/22, the opening through which light passes is small. The result is not a lot of light reaches the sensor. This means the corresponding shutter speed to produce a proper exposure will be slow and necessitates the use of a tripod. It also means that if the subject is moving or if the wind is blowing a delicate subject, motion may be recorded. When all the variables fit together it's great. When they don't, a compromise between a desired aperture and the corresponding shutter speed must be made.
The important concept to glean from all of the above is to be able to predict the end result. Learn how a chosen aperture, its corresponding shutter speed, and focal length interact. Based on the required amount of depth of field you need in the photo, learn what needs to be done in order to achieve it. Set your camera to aperture priority and take charge of the end result.
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