Metering help

[dlhartman]

Man oh man! I've asked this question of various people before and have yet to get an answer that made any sense to me. I'm a Canon 40D owner. Can someone please tell me how to "meter?" I know what the metering settings are. I have a general overview of what each one means. What I don't understand is when someone says they take a meter reading for the sky and then a meter reading for someone's face and set their camera in between the two. What is a meter reading and how do I do it? Is this just involving external flash? I'd love to know how to master this and expose for both the sky and someone's skin at the same time. Thanks.

[inkista]

It might be easier to understand if you're shooting in full Manual (M) mode.

When you're in any other mode, the camera is always metering the scene, but then adjusts your settings so that your meter "needle" is at 0. So you never actually see the needle on the meter move. You just set exposure compensation the way you want it. If you moved the camera around, the needle would stay at 0, and your settings are shifting.

If you're in M mode, though, what you probably think of as your exposure compensation scale at the bottom of the viewfinder is now your meter. You'll see the needle go up and down as you move the camera around and the scene gets brighter or darker, or as you adjust your settings.

Remember, too, that the autoexposure system isn't always right, because of how the metering data is used to set the exposure settings, so maybe your ideal target isn't always to get that needle to 0.

[ravncat]

I don't know what canon calls it, but when people refer to metering someones face, they are also probably using a spot meter mode, which measures light falling on a very small area.

With an inbuilt light meter, this will mean pointing that small spot at the persons face and then half pressing the shutter and noting the exposure.

[RichardTaylor]

Metering is measuring the light.

With in camera through the lens, metering it is normally measuring the light as seen by the camera being reflected from the subject, or in some cases (when looking at a light source) by the light itself.

In your example
(1) You point your camera at the sky (not the sun) & take a note of what the camera displays.
(2) You point the camera at a persons face and take a note of what the camera displays
(3) In manual mode you then set the camera in between the two (if that is what you want)

Depending on the lighting it can be difficult to expose both for the sky and the subject.

If the sun is behind you or off to one side it is relatively easy (and you have a decent sky).

(1) Sun is off to one side.


If the sun is behind the subject, or the subject is in shade, then you may not be able to expose for both without controlling the light on the subject by use of a fill in flash or a reflector to put more light on subject.
If the sky is flat white (overcast) I will try to exclude the sky when shooting.

[autofocus]

I think an understanding of dynamic range would be helpful here.
Dynamic Range = being able to make out good details in both the shadow/dark areas and the bright/ light areas of the same scene.

In photography, we use the term stops as a measurement which covers this range from the very darkest to the very brightest light.

Most of the sensors in today's digital cameras have a dynamic range of about 5 -7 stops (film did cover more)

The human eye/brain can usually see good detail in both shadows and highlights to about 18 - 20 stops

Obviously, the camera is limited compared to what we see. Using standard photography techniques can present a real challenge to get both the very bright sky correctly exposed along with correct exposure on your subject. Unless you are looking for a dark or silhouetted subject, most times you would meter and expose for the subject at the expense of the sky. There are ways to deal with this by using neutral density filters or by taking multiple shots of the same subject at different exposure settings, and then layering them together in the edit process. (known as HDR)

[dlhartman]

Thanks so much everyone! I get it now! It was really pretty simple. Thanks again!