Whether you’re confident and eager or not yet ready to go completely manual, there are two settings on most digital cameras that will make it easier to expose your photos correctly. These are the aperture priority mode and the shutter priority mode. Think of them as your exposure partners; you select one of the exposure settings and your camera automatically selects the other.
Aperture Priority Mode
When you put your camera in aperture priority mode, you will typically see the symbol “A” or “Av.” You then select an aperture (an f-stop) that you think is correct for the specific conditions of the digital photo you want to take. Because you now know that a large f-stop number (f/22 or f/16) makes the lens opening small and a small f/stop number (f/1.4 or f/2.8) makes the lens opening larger, you should be able to come close when choosing the right aperture. If you’re outside and it’s a bright, sunny day, then, in most cases, you want a small opening or a large f-stop number. If you’re outside at dawn or dusk or indoors, then you know you need the lens to be open wider, so you’ll select a smaller f-stop number. Then, your camera will automatically select a shutter speed that, in combination with the f-stop you chose, will give you the right exposure.
The aperture priority mode will be specifically helpful when you want to control depth of field in your digital photos. If you’ve read and practiced the tips in Part 4, then you now know that your aperture setting has a direct effect on the depth of field in your photos. Selecting a large aperture or lens opening results in shallow depth of field; a small aperture or lens opening makes virtually your entire photo appear to be in focus.
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You want to shoot a close-up of a small object, but blur the background, so the object is more prominent; therefore, you want a shallow depth of field.
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During your vacation, you want to shoot a beautiful landscape of the sun and beach or a valley with a backdrop of mountains. You would then select an f-stop to create a very deep depth of field.
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Once you choose the right aperture for the depth of field you want, the aperture priority mode will set the matching shutter speed.
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Two important points to remember: first, when your camera automatically sets the shutter speed, it may select a speed so slow (1/60 or less) that you will need a tripod to keep the camera steady. Second, a slow shutter speed could blur your subject if it is moving.
Shutter Priority Mode
You may have already guessed that the shutter priority mode (a Tv or S symbol) does just the opposite of the aperture priority mode. Now, you select the shutter speed manually and the camera sets the correct aperture. Don’t make the digital photographer’s mistake of using either of these modes as a crutch, so you don’t have to think about making the right exposure choices. Just as aperture directly affects depth of field, shutter speed directly affects how you capture the movement of subjects and objects. Controlling that movement is the primary reason you use shutter priority mode.
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Select a fast shutter speed (1/500, 1/1000, etc.) if you want to freeze a moving object: a beautiful horse running in a meadow.
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Select a slower shutter speed (1/125, 1/60, etc.) if you want to create the effect of the horse in motion. The slower the shutter speed, the more the object will blur.
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Once you select the appropriate shutter speed, the priority shutter mode will set a matching aperture or lens opening, depending on the lighting conditions.
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Another reason you must think when using the shutter priority mode is that your camera may choose an aperture that creates a depth of field you don’t want. If you select a fast shutter speed to freeze the motion of the horse, then the depth of field of your digital photo will be shallow.
As with the entire digital photography tips in these articles, the best learning experience is to practice shooting in the aperture priority mode and shutter priority mode. Select different aperture and shutter settings, outdoors, indoors and with different levels of light, and then compare your results.
Recommended Reading:
- Understanding Exposure: How to Shoot Great Photographs with Any Camera
- Understanding Shutter Speed: Creative Action and Low-Light Photography Beyond 1/125 Second
- BetterPhoto Basics: The Absolute Beginner's Guide to Taking Photos Like a Pro
- The BetterPhoto Guide to Digital Photography
- The Digital Photography Book
- Creative Shutter Speed: Master the Art of Motion Capture
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