What Does the M on My Camera Mean?

In previous posts, I've explained what the letters P (Program), S (Shutter Priority) and A (Aperture Priority) on the exposure dial mean. This time I describe the letter "M," which stands for "Manual" exposure mode. With this setting you are completely in charge of all three controls that affect your picture's brightness: ISO (light sensitivity), shutter speed, and aperture (f/number). The camera does not make any choices for you automatically.

Cleaning out the Greenhouse
1/160 second, f/8, ISO 200

Using manual exposure mode gives you complete creative freedom to control how motion, sharpness and light sensitivity are presented in your photograph. Manual exposure can be helpful when you are working under constant lighting conditions, such as a cloudy day outside or a gymnasium indoors. Once you determine your preferences for subject motion, background sharpness (depth of field), and light sensitivity (ISO), you can forget about them for the rest of your photo shoot. Because the lighting is not changing, your exposure remains constant, no matter how background or foreground brightness might vary.

Judging Sheep
1/250 second, f/4, ISO 2000

Just like the other letter modes, your built-in flash does not fire automatically in manual exposure mode. If you want to use flash, be sure your shutter speed is not faster than the flash synchronization speed. See your camera manual for this information.

Learn about manual exposure in my Mastering Manual Exposure class coming Fall, 2018, in Missoula, Montana.