Nikon Metering - 3D matrix metering

The Nikon equivalent of "pattern" metering on other cameras has some interesting characteristics to be aware of . First of all it is called "3D colour matrix metering " for a reason . Hopefully these pictures will illustrate the point I am trying to make without too much talk . [ Taken with a D90 - each model varies slightly with matrix metering ]


These two pictures don't look much different though the one where the focus point is on a dark object is slightly brighter , however all the white in the scene causes some under-exposure in both images....






But watch when there is a lot of black in the scene ....






Simply moving the focus point to a dark object changes the exposure , by up to two stops in some scenes , for exactly the same scene with matrix metering . It seems to react more strongly to 'shadows' when it exposes .
Also the fact that they are at different distance from the camera causes a bigger change - when they are the same distance the "3D" aspect exposes similarly for them .
Matrix metering works quite well in most cases but when you have a high contrast situation be careful of over-exposure and learn how to use exposure compensation .

Here's a real world example . The same scene , taken using a tripod , and all I've done is move the active focus point ! ....

Focus point on the left .... 1/125th sec



focus point on the right .... 1/500th sec .... 2 stops difference !