Alan Louie Offline Upload & Sell: Off
|
p.1 #7 · Manual mode and metering type question | |
The meter is changing because it's analyzing it differently. Matrix mode looks at the entire scene that the sensor sees and gives you a 'good balance' to expose as much of the scene properly as possible. When you change it to spot, it's looking at one tiny spot and evaluating the best way to expose only that spot.
So, scenario 1, your meter is saying... well.. we can go either go after the light background or the light subject (although it doesn't know it's a subject). On the assumption that the meter is dumb (and Nikon's metering doesn't seem to be that), it will expose properly for the vast majority of the scene, the bright background. Therefore your dark subject will be underexposed.
Now when you switch to spot metering and put it on the subject, it evalutes how much light you need to expose ONLY that tiny spot that you have it staring at. It completely ignores everything else.
So, in scenario 1 the subject would be underexposed. Now since you're not changing anything and putting the spot meter on the subject, it should say in scenario 2 that you need to overexpose by some amount of light from your current settings. As you increase your aperature, decrease your shutter speed, or increase iso (all ways to increase the amount of light hitting the sensor), you will bring that meter back to zero because then it will be happy! But when you take the shot, your background will be overexposed.
Now if you hold those new settings and switch back to matrix, it should show that you need to underexpose by exactly the same amount as you had just adjusted it from scenario 1 to scenario 2.
Let me know if I confused you more.
|