When set to the Program mode, the camera sets the shutter speed and ƒ-stop for a correct exposure of the scene. However, at a moment’s notice, you can change that combination (to a slower/faster shutter speed or to a wider/smaller ƒ-stop). That’s because the Program mode on most cameras is what’s called an adjustable or shiftable program mode—meaning you can make adjustments in your shutter speed/ƒ-stop choice while you’re shooting. So, if you want the background or foreground more or less in focus, or if you want to blur or “freeze” the subject, you can make an adjustment quickly and easily—by turning a wheel that adjusts the ƒ-stop and shutter accordingly. This doesn’t change the actual exposure of the scene. I used the Program mode for this Arches National Park photograph.
If precisely controlling motion in a picture is your objective, set your camera to the Shutter-Priority mode. Use fast shutter speeds (usually above 1/250th of a second) to “freeze” action and slow shutter speeds (usually below 1/30th of a second) to blur action.
I “froze” this pelican with a 1/500th-of-a-second shutter speed, and I blurred the water in this photograph of the rapids at Niagara Falls with a 10-second exposure.
The beauty of this mode is that even if the light level changes, the shutter speed stays set. This is because the camera automatically selects the appropriate ƒ-stop for a correct exposure.
When precisely controlling depth of field (the area that’s in focus in front of and behind a subject) is important to the photograph, use the Aperture-Priority mode.
The beauty of this mode is that even if the light level changes, the ƒ-stop stays set, because the camera automatically selects the appropriate shutter speed for the exposure that you’ve chosen.
Here we see how choosing a wide ƒ-stop (ƒ/2.8) offers shallow depth of field. The background in this portrait of my friend Chandler is very blurred.
Here’s how choosing a small ƒ-stop (ƒ/11) offers greater depth of field. In this picture, which I took in Bhutan, both the young monk and the dzong (temple/fortress) in the background are in focus.
Manual Exposure (M) Mode
For total exposure control, especially in tricky lighting situations that can fool a camera’s exposure meter, choose the Manual Exposure mode. In this mode, you separately set both the shutter speed and ƒ-stop for a slightly darker or lighter picture (or background). You can also change the settings to control the degree of subject movement, as well as subject movement vs. background movement, and vice versa.
This Botswana sunset was already spectacular. To enhance the colors, I set the exposure to one stop under the camera-recommended setting while in the Manual mode.
To capture the beautiful sunset in the background and the couple in the foreground, I used an accessory flash and dialed in the correct ƒ-stop shutter speed combination while in the Manual mode, which let me fine-tune this tricky exposure in a tricky lighting situation.
I selected a relatively slow shutter speed (1/30th of a second) and wide aperture to blur the background and capture just a touch of movement of this butterfly’s wings.
Now that you see the reasons for, and advantages of, the creative exposure modes, I hope you take the time to use them and be more creative with your pictures!
Rick Sammon has published 27 books. Visit www.ricksammon.com for more information, and meet up with Rick at one of his PCPhoto/Outdoor Photographer workshops.