How do evaluative, center-weighted, and spot metering differ?

They differ in which parts of the scene the camera considers when measuring brightness:

• Evaluative: considers multiple areas across the image. Depending on the camera, it may also use factors such as subject position or an active autofocus point. Canon describes such behavior for the PowerShot models covered by its support article; it is not a universal specification. [S1]
• Center-weighted: meters the whole frame but gives more emphasis to the center. [S1]
• Spot: meters within a smaller, designated spot frame. Its exact coverage and behavior depend on the camera. [S1]

As a rough mental model: multiple areas, whole frame with center emphasis, and a small area. The mode affects what the camera considers; it does not guarantee a particular exposure result.

Here’s a comparison chart. The suggestions are starting points for deciding what to try, not rules about which mode will work best.

Evaluative

• Considers: Multiple areas of the image; some cameras may factor in scene details such as subject position.
• Consider it when: You want the camera to assess the broader scene rather than prioritize one small area.

Center-weighted

• Considers: The whole frame, with greater emphasis on the center. [S1]
• Consider it when: You want the central part of the composition to have more influence on the reading.

Spot

• Considers: A smaller area within the spot frame. [S1]
• Consider it when: You want to focus the reading on a particular small area and can identify where that area is in the viewfinder or display.

Canon notes that evaluative metering may be linked to active autofocus points in some systems, and gives coverage details for the systems it discusses. Those details are not automatically true of other cameras. [S2] To see how your camera responds, keep a scene and framing similar while changing only the metering mode. Compare the results; this simple exercise does not predict every situation.

The main pitfall is assuming a mode name tells you its exact coverage or behavior. “Spot,” for example, does not establish how large the spot is or whether its position can change. “Evaluative” does not specify which scene factors your camera uses.

In your manual, check:

1. The exact mode names and descriptions.
2. Which part of the frame is measured, especially for spot metering.
3. Whether the metering area can move or is tied to an autofocus point.
4. Which shooting modes allow each option.
5. Any model-specific notes about how readings are combined or prioritized.

For the PowerShot models covered by one Canon support article, the described function is available only in P, Tv, and Av modes. That restriction applies to the models covered by that article, not necessarily to other cameras. [S1] If a detail is unclear, don’t assume another model’s coverage or behavior applies.

Use this note and fill in only what your manual confirms:

Camera/model: [model] Evaluative or equivalent: [areas or factors described] Center-weighted or equivalent: [area measured and emphasis] Spot or equivalent: [location, coverage, and whether it can move] Availability or restrictions: [shooting modes or conditions] Unclear details: [questions to check]

For a simple comparison, photograph a stationary scene with bright and dark areas. Keep the framing and other settings as consistent as practical, take one frame in each mode, and note which mode you used. Compare the results, then try a second scene with a different arrangement of bright and dark areas. This shows how your camera responded in those examples, not how it will behave in every situation.

The broad distinctions are useful, but names, coverage, and behavior can vary by model. Check your own manual for specifics rather than relying on another camera’s figures. [S1][S2]