Automatic metering systems

Depending on the camera you own, you can switch between three basic metering settings
1. center weighted metering


2. matrix metering


3. spot metering

Refer to figure 4-3 on the book.
These two photos of a water lily were taken within moments of one another. Using the same light source and same subject, different metering methods were used. Obviously the shot (A) was shot overexposed because of the wrong metering method was selected. The meter measured the light from the shadow reflection in the water and it resulted in an overexposed photo. The (B) photograph used spot metering to measure the brightest part of the flower, resulting in a proper exposure of the flower. While the background of the photo is a little dark it’s an acceptable compromise.

Center-Weighted Metering

Center- Weighted Metering describes a metering system that measure the light in the entire scene and averages the exposure of the scene, giving extra weight to the light readings in the center of the frame. Center-Weighted metering assumes that the subjects is in the center of the frame and therefore uses the light measured from the center to influence the overall exposure of the photo. Center-weighted metering works best when the light source is behind the subject or when the subject is white or very light.

When shooting with center-weighted metering, remember that the camera is measuring the light at the center of the image, so if your subject is off-center, you will need to use exposure lock to read the light on the subject before composing the photo. You can also use center-weighting when the subject is white or a very light color.

Matrix Metering

Matrix metering represents the most complex metering mode, and how it works differs among camera brands. Matrix metering breaks up the image into a matrix of metering zones; each zones is evaluated to determine the best possible exposure.

Spot metering

Spot metering allows you to measure the lighting at the center of the image. Like center-weighted metering, the most common use of spot metering is also used when the subject is much brighter than the background, to prevent blowout.
*A blowout is an area of a digital image that has gone 100% white.

Understand exposure values

The amount of light that strikes the camera’s sensor is controlled by two factors: how much the light is let into the camera (via the aperture) and how long is on the sensor (shutter speed).

The EV is measured in decimals or whole steps. Positive steps such as +.5, +.7, +1, and +1.5 increase the exposure, making the resulting photo lighter with each increase; negative steps such as -.5,-.7,-1, and so on, make the exposure darker with each decrease.

The decimal settings produce a small change in the overall exposure, while a setting of 1.5 or 2 will significantly change the exposure.

Making the best available lighting

The quickest and easiest reflector you can use when the light is behind your subject is your own body. If you are wearing white clothes, you can become a natural reflector. Be careful when photographing a subject standing near a brightly colored wall, because like reflector, the light reflecting off the wall may add unwanted color to your photograph.

Block the sun to get the shot

To take a photo under such conditions, you can find some object in the foreground that you can place between you and the sun.