… before we go to the nice and warm Philippines…
I’ll make this an exposure 101. If you’re a pro-photographer you already know this (or at least, you should! 😉 ), but I’ve been asked about this a couple of times and I decided to do a simple, little write up about it, without getting into too technical language.
Why is it important to take (manual) control of your camera?
A lot of people, especially those who have just bought a camera or have just gotten into photography, use the automatic settings in the camera. In most of the average cases that would be just fine, but since a camera is just a thing, with no obvious intelligence, when things get out of average, the picture goes south as well.
My camera is set (in 95% of the cases) to full manual with spot metering. I prefer spot metering above all other settings, because I get to pinpoint a location in my frame for which I decide what exposure is the best one, based on the initial suggestion of the light meter in the camera.
The other metering methods are also working fine, but don’t just blindly trust the values the light meter in your camera shows you.
What you need to know about the camera’s light meter, is that it’s “calibrated” to assume that everything in your frame has an average hue. The light meter doesn’t see or read colors, it just sees light or dark. 18% grey may sound familiar to some of you, maybe not to others. But 18% grey is what the light meter thinks the average hue in your image is (or rather, should become). Green grass, for example, is about 18% grey, on a normal sunny day. So if you were to take an image of a sports field with mostly grass and you’d have your camera do everything automatically, you’d have a great picture with a perfect exposure. Of course there are plenty of other things that are -about- 18% grey. But what if you’re shooting somewhere where everything, or the bigger part of your frame, is NOT 18% grey?
If that were the case, and you have your camera set to automatic (or to manual, and you’d dial the exposure, ISO and/or aperture so that the bar sits nicely on the 0 in the middle), your camera will make everything 18% grey.
The perfect examples are in the two extreme ends of the light spectrum.
Imagine a winter landscape, with mainly… yep: snow. Snow is one of the purest, whitest substances on this planet (provided it’s not territorially marked by some inhabitant of this planet 😉 ).
So what would happen in the camera when I’d point it at my winter landscape? The meter sees the landscape and ‘thinks': “Wow! That’s easy! A big frame full of 18% grey.” And so, thinking the purest white snow is 18% grey, the camera underexposes your image with about 2 stops.
In order to correct this, and to get the right exposure for the snow, you’d have to manually adjust the exposure time either by dialing up it with up to two stops, or use the exposure compensation.
The same thing goes for the other extreme of the scale. When what you see in your viewfinder (or your Liveview screen) is primarily black/dark, the light meter will assume that this is 18% grey and will adjust –overexpose in this case- the exposure to make the blacks look like 18% grey. You will have to underexpose the image to correct for the camera’s false assumptions.