Reading the Exposure Level on Your Digital SLR Camera
Your digital camera has an exposure level indicator scale (a.k.a. exposure scale or exposure meter), shown here. The center of the scale (sometimes labeled with a 0 but often with just a slightly different mark) indicates a standard exposure — the combined exposure value with inputs from all the camera’s exposure settings that the camera thinks will produce the best photo.
The numbers to the left and right of center tell you how many stops — or levels of exposure value (EV) — you are away from the center. As you know by now, negative numbers indicate values that would underexpose the photo. Positive numbers indicate values that would cause overexposure.
The size of the scale may vary, but cameras usually show a minimum of +/- 2.0 EV from the center. Some cameras have displays that read +/- 5.0 EV. Normally, the vertical bar under the scale, known as the exposure level indicator, predicts a photo’s exposure, relative to the standard exposure, taken with the current meter reading and using the current exposure settings.
In autoexposure modes, the exposure level indicator stays pegged in the middle. After all, that’s the point of autoexposure. In manual mode, the exposure level indicator moves depending on your exposure settings. If you set your exposure settings so that the exposure level indicator is on 0, you’ll take the standard exposure. The exception to that is when you are in manual mode and have set the camera to Auto ISO. As you make changes to shutter speed and aperture, the ISO will automatically adjust to keep the exposure at 0 EV.
After you set the exposure in manual mode, the settings won’t change between shots, even if the meter displays a slightly different light level. Shooting in manual mode is an excellent way of making sure that your photos consistently use the same exposure settings, which is to your advantage when processing them the same way later.
The indicator can move left or right when you’re in an autoexposure mode by a process known as exposure compensation. When you’re shooting with autoexposure bracketing, each bracket’s exposure is often marked with a tick mark.