METERING PROBLEMS

IF THE METER IN YOUR CAMERA IS HIGHLY ADVANCED, WHY DOES IT GET THINGS WRONG?

The reason why your camera doesn’t always nail the correct exposure is that it meters the light reflected by the scene — and some subjects reflect more or less light than others. Camera meters are designed for 18% reflectance — in other words, if a subject reflects about 18% of the light that falls on it, the camera should produce a ‘correct’ exposure. Mid-tone subjects such as grass and grey pavements reflect roughly 18% of the light, and many scenes average out close to this value. But when it’s faced with an overall dark subject, the camera will read this as a mid-tone subject that’s not receiving enough light, and will extend the exposure — making the subject look too bright. With a bright subject, the camera will see a mid-tone subject that’s receiving too much light and reduce the exposure, making the subject look too dark.