A weekly trio of top photo tips
Matrix metering or evaluative metering as it is also known, is the modern and tried & tested standard metering mode for digital cameras. The camera evaluates the whole picture, taking into account subject and scene and calculates the correct exposure for a great picture. Most of the time it works well, but it’s not infallible. There are situations and lighting conditions that can confuse it. In these circumstances, or just when you want to take more control, there are other options.
Centre-Weighted
Before matrix metering, the most common metering mode a camera had was centre-weighted metering. This is going back to the days of film cameras, but many modern digital cameras still have this as an option. As the name suggests it takes a reading from the whole frame, but biases its readings from the centre of the frame, where it expects you to be placing the main subject (of course, this isn’t necessarily the ideal for most compositions!). It’s still a good general one for measuring portraits and landscapes, but like matrix metering, it can get easily fooled in tricky lighting conditions.
Centre-weighted metering
Partial
To take more control of your metering measurements, select partial metering. This takes a reading from the central part of the frame (usually designated in the viewfinder by a large circle etching). Unlike centre-weighted metering however, it not only ignores the rest of the frame, but you can usually lock and hold the reading, by half-pressing the shutter button, so you can recompose and not have to place your subject dead-centre. Used with care you can achieve accurate exposures every time, even in tricky light such as shooting backlit subjects.
Partial metering
Spot
Taking things further, spot metering takes a reading only from the small circle in the centre of your viewfinder. Point this at any area of the scene or subject and you can take small and accurate readings or even multiple readings, which the camera will evaluate. Where you point the spot-meter has to be taken into consideration however. Ideally, this should be from an 18% reflective grey area, as this is how your camera sees the world. Pavement or grass matches this tone and therefore these subjects make ideal areas to take a reading from, whereas white or black areas or subjects for instance, will require a 2-stop exposure adjustment to keep them at their correct density.
Spot metering
You can read more about camera metering and exposures in my eGuides. These are available as part of an e6 subscription or to purchase separately. www.e6subscription.co.uk
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