Part 8 Lesson 3: METERING
In this lesson you will review how to use spot metering to eliminate exposure errors in macro photography. This lesson corresponds to Chapter 20 in Book 2.
Spot metering
Do you remember from the very beginning that the camera assumes the world is approximately 18% grey, and exposes every image on that basis?
Do you also remember that your camera has 3 ways of measuring the light falling on a scene, called metering modes? Your default metering mode will either be matrix or evaluative metering, or centre-weighted metering. In both of these modes the camera takes an average reading from a broad area of the frame. This is usually fine if you are taking a normal photograph, but with macro photography it can create some very unusual exposure readings.
To get more precise metering with macro photography (or indeed any photography), pick something in the frame which is approximately 18% grey, and use spot metering to meter off only that point, nothing else.
By using spot metering you can make sure you are metering off something that is approximately 18% grey. Evaluative/matrix metering would give an underexposed image for this shot because it is mostly paler tones. But if you meter from the area that the red arrow is pointing (which would convert to a mid-grey tone), the whole image will be correctly exposed from the start.
THIS WEEK'S PROJECT: spot metering
1. Look up in your manual how to turn on spot metering.
2. Using the same settings as for the last 2 lessons, take a macro image except this time use spot metering to meter off something that is approximately 18% grey. If there is nothing 18% grey in your shot, you can temporarily add something (like a grey card) to get the exposure, and then move it out of shot when you press the shutter.
3. If you want to, shoot comparison images using evaluative/matrix metering as well.
4. Don't forget to switch back to centre weighted or evaluative metering when you're finished.
How was it? Do you prefer using exposure compensation? Did you know you can't use exposure compensation when you're shooting fully manual? If you want to be able to shoot macro images efficiently, spot metering is one of the things you need to learn. If you're happy taking it slower, and maybe not using manual mode, you don't need to remember everything from today's lesson.
Don’t forget there’s an A Year With My Camera app where you can meet other people doing the course. Search on your Apple or Android app store, or click here for more details.