Canon: The Right Way of Metering

Canon has 4+ metering modes:

1. Evaluative Metering
2. Partial Metering
3. Spot Metering
4. Center-weighted Average Metering

And then there’s the manual mode. So what’s the right way? That depends:

• On the direction of the wind
• The age of the captain
• What about the exposing to the right?

Does this sound whimsical? Because exposure is whimsical. There’s no right exposure. It just depends. The metering is only one step in the exposure. EV7 = 1/30sec @ f/2 and ISO 100, but it’s also 1/125sec @ f/2 and ISO 400, and… Exposure is only one step.

The second step is the processing.

The third and more important step, what’s the purpose or the intent. That step happens before the metering and after the metering when doing the processing.

Photos of somebody in the snow, should you over-expose? Everybody will tell you yes, but I say that it depends:

1. Evaluative metering? With the focus on the person in the snow, and the person is at least ¼ of the image, then no, no over-exposure. 50% of the metering is done on the point in focus and on the points around the point in focus, then there another 10 to 30% that is done on the points that are almost in focus.
2. Partial metering? If the person’s face or main “components” are covered by the 9% in the center, then no, no over-exposure.
3. Spot Metering? I would personally place the spot on the face of the person and recompose, then no, no over-exposure.
4. Center-weighted Average Metering? Then yes, I would overexpose by 1½ to 2½ EVs

Now let’s change the subject from a snowing scene to the face of a black and white dog, where half of the face is white and the other half is black.

1. Evaluative metering? With the focus on the eyes which are almost always back, the photo will be overexposed, so I would under-expose by ½ to 1½ EV.
2. Partial metering? If the person’s face or main “components” are covered by the 9% in the centre, then no, no over-exposure.
3. Spot Metering? I would personally take 2 readings, one of the white, the other on the black and then split in the middle. But isn’t that the equivalent of the center-weighted average metering?
4. Center-weighted Average Metering? It usually gives me the best results when I deal with faces/portraits…

Remember that:

1. All reflective light meters, all brands and models, measure an 18% grey.
2. Some people claim that Nikon and Canon’s light metering system is calibrated to measure a 12% grey. Not important any more, since now they both measure color brightness on most of their dSLRs.
3. A reflective light measurement of an 18% grey card is the equivalent to the incident light reading of a hand held light meter.
4. Ansel Adams wasn’t a great photographer! He was a good photographer and a fantastic, outstanding and superb “lab rat.” He spent weeks on-end in his lab, just to get the right look.