When using a camera’s light metering system it requires some knowledge of what settings to use to get the best exposure for your image. With the Nikon cameras there are essentially three different metering settings to understand when measuring the light levels. Spot metering, centre weighted spot metering and matrix metering, some knowledge of these is required to get the best out of your camera.
The above image has been exposed using matrix metering.
Spot Metering
Spot metering is a metering method in which the metering sensitivity is concentrated within a small circle in the center of the viewfinder. Recommended for very precise metering, this setting requires an extensive knowledge of lighting for really effective use.
Most camera meters will measure in a small circle of around 4mm or 1.5 % of the area of the viewing frame. The circle is measured is generally the currently used focus point. Spot metering can be very effective with very bright or dark backgrounds to select the specific subject.
Spot metering can also be used to meter specific areas of an image and to determine the dynamic range of images.
Centre Weighted Metering
The centre weighted metering measuring sensitivity is biased toward the centre of the viewfinder. Recommended when the subject is in the center of the picture with subjects such as portraits. Generally an area of around 12mm in the centre of the image is used.
Matrix Metering
Matrix metering is an advanced metering mode in which the camera’s internal computer calculates and sets the exposure based on the analysis of the components of the specific scene. This is regarded as the most accurate metering for most lighting situations, especially when there is complex lighting present. I favour this method for most of my photography.
Matrix Metering or 3D Colour Matrix Metering gathers the information from the red, green, and blue sensors and factors in distance information, which is provided by the lens, as it evaluates the proper exposure calculation. This metering system will instantly analyse the brightness of the image, the contrast, and other lighting characteristics. All the characteristics of the scene are compared against a database of over 30,000 images to achieve the correct exposure. When the 3D Matrix metering has made its calculations of the colours, hue, saturation, tonal range, areas of similar tonality, distance to the subject and compared that to its database, generated from photographic images, it will then calculate the exposure value required.
Matrix metering is the easiest metering arrangement to use to get excellent exposures and superb images. I use it 95% of the time.