Spot metering and AF
Spot metering is really useful for high-contrast lighting or other difficult shooting conditions, but the results can be unpredictable.
On many DSLRs the spot reading is taken from the current AF point, so if you’re using Auto-area AF this means the exposure may change each time the camera swaps autofocus points – another good reason for using single-point autofocus!
Set spot mode
On our Nikon D300s, there’s a metering pattern dial on the back of the camera. Here, it’s set to Matrix mode – the spot mode setting is directly below.
Spot metering point
Linking the spot area with the focus point works well here because we want Sarah’s face correctly exposed and in focus. We’d get a different exposure, though, if the AF point was over the background, or the bright white areas of her dress. This is why you need to use the spot metering mode with a good deal of care.
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