Understanding the Exposure Mode Dial

Gentling the gelding

I just posted a list of my upcoming digital photography classes at The Lifelong Learning Center in Missoula, Montana. The course for beginners called "Getting to Know Your Digital SLR Camera" usually generates at least a couple phone calls from people wondering if their camera is the kind mentioned in the title. In order to benefit the most from this beginning class, your camera needs to provide you with the ability to change the shutter speed, aperture and ISO settings. Even if you don't know what these terms mean yet, you can still figure out if your camera will work for the class. Here's how.


Mid-level and professional model digital cameras have a dial, usually on the top of the camera, that provides a variety of exposure methods to choose from. Here's a picture of the typical dial on both a Canon and Nikon camera. Even if you have a different brand, it likely has a dial with similar symbols on it.


Even some compact or "point and shoot" camera models have dials with the same icons.

Notice that about half of the dial contains little pictures or icons while the other half shows just letter abbreviations. All dials have a fully automatic exposure mode. This is usually green and may be a square, a camera or the word "Auto". Setting the dial to this symbol allows you to point and shoot your pictures while the camera makes all the decisions about the exposure settings.

The icons represent different subjects or shooting situations. They are also completely automatic settings, but the camera chooses different ones from what it might pick in Auto in order to give you better results for that subject. For example, the camera chooses very different settings for the mountain (landscape) icon than it does for the lady (portrait) icon. But because these are automatic, you might not always get a picture that looks the way you want.

On the other half of the dial are the letter icons. These are semi-automatic and fully manual exposure settings where you tell the camera at least some of the settings to use. Here's what they stand for:
P = Program; a semi-automatic exposure setting in which you select the ISO (sensitivity) of the camera's sensor and the camera picks the shutter speed and lens aperture for proper exposure; you can also adjust other controls if you don't like the results.

High ISO indoors by candlelight
Low ISO outside in daylight
S or Tv = Shutter Priority or Time value; a semi-automatic exposure setting in which you select the time the shutter curtain is open to allow light to reach the sensor, such as 1 second or 1/250 second.  This allows you to decide how you want motion to appear in your picture---blurred (1 second) or stopped (1/250 second). The camera then selects the lens aperture for a proper exposure.You can also adjust the ISO and other settings the same way as in Program exposure mode.

Blurred motion
Stopped motion
A or Av = Aperture Priority or Aperture value; a semi-automatic exposure setting in which you select the size of the lens opening to let light hit the sensor, such as f/4 or f/16. This lets you decide how you want the background to appear in your picture---blurred (f/4) or sharp (f/16). The camera chooses a shutter speed for a proper exposure. You can also adjust the ISO and other settings the same as in Program and Shutter Priority.

Blurred background
Sharp background
M = Manual; a completely manual exposure setting in which you choose the ISO, shutter speed and lens aperture for the exposure and look you want in your picture. The camera chooses nothing. This gives you the most creative freedom in the exposure and appearance of your final image.

Manual exposure

Manual exposure
Regardless of what style of digital camera you own (DSLR, mirrorless or compact), if it has these  letter settings, you can learn to use them to make photographs instead of take snapshots. Check out my class or another introductory camera class in your area to learn more about how your equipment works.