Datasheet

c h a p t e r 1: DIGITAL IMAGING BASICS, WORKFLOW, AND CALIBRATION ■

Figure 1.15 Evaluate the exposures for the best overall exposure and zoom into the most likely candidates.

Look for the exposure that gives you a reading close to 51 percent and, very

importantly, without having the white patch go over 90 percent. Move the cursor into

the image and look at the numbers that show up right under the histogram display,

as shown in Figure 1.16. In my example, the gray patch is closer to 51 at the ISO 64

exposure where it reads 53 percent; however, the white patch is 100 percent, clipped.

The next exposure down would give me an ISO of 80, and here the gray patch is at

48 percent. This one still doesn’t quite work because the white patch is 93 percent

(Figure 1.17). So, in the end, I’m back to ISO 100 where the gray patch now reads 43

percent but the white is at a safe 85 percent (Figure 1.18). Once you have found the

ideal exposure, you can calculate what kind of compensation you will need—plus

⁄

to plus 1 stop are common.

It is also common for this compensation factor to be different, depending on

the color temperature of the light. For my Canon 5DmkII, the compensation for direct

sun is +

⁄

, for open shade it is 0 (no compensation), and for tungsten it is +1. Most

of the time, you can enter this compensation into your camera settings if you rely on

your in-camera meter. I will typically enter an average exposure compensation across

all three lighting types for my in-camera meter settings and just leave it there. Another

thing to consider is that you can often recover up to one stop of highlight detail with-

out suffering image degradation, but using Fill Light or something similar to recover

shadow detail will result in extra noise. So… if you are going to err, err on the side

of over exposure. In my case for this camera, I would use an exposure compensation

in camera of +

⁄

even though that would be overexposing in open shade lighting. I

only need to put the Recovery slider at 20 to get the white patch to read 89 percent

(Figure 1.19).

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