photokaboom

Learn Photography

Beecher's Handouts > Camera >

3.8.4 - Default Settings >

4 - Light Meter

Your camera has a light meter that measures the amount of light in a scene.

What this light meter "sees" can be changed.

There are three light metering patterns:

• Multiple point

• Center weighted

• Spot

Multiple Point

The multiple point light meter setting is called matrix metering on Nikon cameras, and evaluative metering on Canons.

When using the multiple point light meter setting, the light meter measures many points on the frame.

Before the shutter opens, the data from these many areas is compared to thousands of patterns, called algorithms, stored in your camera's computer.

If there's a match between the pattern of the scene you're photographing, and one of the algorithms, the computer will base the exposure setting on the matching algorithm.

The reading at the focus point will be given greater weight, as this is probably the subject of the photograph.

Therefore, when you're using multiple point metering, set your focusing system to where the focus point is decided by the camera.

The multiple point light meter setting works well—but not all of the time.

Where setting the best exposure may be tricky—compare multiple point metering with center-weighted or spot metering (described below).

When Is Setting the Exposure Tricky?

Contrasty scenes and backlighted subjects can confuse the multiple point light meter setting.

Your judgment may be better than that of your camera's computer.

Use the center weighted or spot light meter settings.

Center Weighted & Spot

Center Weighted

With center-weighted metering, the light meter measures most of the light (60 to 75% depending on the camera) in the central area of the frame.

For example, if you're photographing a landscape, and you don't want a bright sky throwing off the exposure, point the central area of the frame down, removing the sky from the frame.

Lock in the exposure using the autoexposure lock button (AEL button on Nikons, star icon button on Canons).

Then, recompose your photograph in the frame.

Go to Autoexposure Lock.

Spot

With spot metering, the light meter measures a small area in the center of the frame.

This area may be from 1% to several percent of the entire area of the frame.

On some cameras, you can adjust the size of the area.

For example, if you're photographing an eagle nest against a bright sky, point the center of the frame at the nest.

As described above, lock in the exposure using the autoexposure lock button (AEL button on Nikons, star button on Canon Digital Rebel XT).

Then, recompose your photograph in the frame.

None of the Above Work

For this Situation

If you're photographing a subject that's very light colored or toned, or dark colored or toned, all of the above metering systems will fail.

Your judgment will be 100% better.

For example, if you're photographing snow in the sun, all of the above metering types will underexpose (darken) the snow.

Similarly, if you're photographing the face of a gorilla, all of the above metering types will overexpose (lighten) the gorilla's face.

You have to measure the light in the scene on a surface that's medium colored or toned.

Lock in this exposure, and recompose the scene in the frame.

Go to Light Meters Are Stupid.