Photofocus

Copyright Scott Bourne 2008 - All Rights Reserved

There are plenty of places to get basic exposure tips. Just enter the phrase “Basic Photo Exposure Tips” into Google and you’ll see what I mean.

Since the basics are easy to come by, I decided to write a post on some advanced exposure tips.

I usually recommend using your camera with matrix or evaluative metering. These modes evaluate the entire scene, comparing levels of brightness, and then, using proprietary algorithms, come up with a “correct” exposure. Most of the time, the evaluative meter works just fine.

The key to advanced exposure technique is paying attention to the tonality of an entire scene, the tonality of the primary subject and the size of the subject in the frame.

If you can do this regularly, you’ll soon be setting exposure accurately and getting good results nearly every time.

Let’s look at a few common situations.

Main subject is very dark or black:

If the dark subject is taking up most of the frame, you’ll need to underexpose a bit. If using evaluative metering in aperture priority, or another auto exposure mode, set your exposure compensation to around minus one (-1)

If the dark subject is small in the frame, 25% of the frame or less, and the surroundings are generally medium, use no compensation.

For greater accuracy, you can use your spot meter in the manual mode and try either one of the following techniques.

One solution that works well is metering off something else in the scene besides the subject.

Is there a medium toned rock, tree bark or grass in the scene? You can preset your exposure based upon something that’s of a known medium tonality and in the same light as your subject. Remember, if you get the medium tonality right, the rest of the picture will fall in place, providing everything is in the same light. This is especially helpful if the subject is small in the frame.
There are two notable exceptions: when the subject is black or white. A black subject is two stops (or more) darker than medium, which will be rendered black, without detail. Just the opposite happens with a white subject. The white subject is two stops lighter than medium, which ends up white without detail.

If the subject is black, and you base your exposure off the surroundings, chances are that the subject will come out too dark on film. From my experience, if you want detail in the darkest areas, basing the exposure on the surroundings and opening up (meaning adjusting toward the + and not the -] about 1/3 to 1/2 of a stop works well.)

The same kind of strategy applies to white subjects. Only this time, to preserve the highlights you’ll need to slightly under expose. About -1/3 to -½ stop should deliver the results you’re looking for.

This seems opposite traditional reflective metering techniques where you would overexpose white and underexpose black. However, keep in mind we’re not basing the exposure off the subject in this case. If we were, we’d end up with the exact same setting.

What we’re actually doing is a using a combination of reflective metering technique (basing the exposure on the surrounding) and incident metering techniques (compensating for the tone of the subject.) Since we’re not using incident meters, I’m not going to go into the theory behind exposure compensation using incident meters.

Let’s say you’re photographing a black subject and that subject is taking up about 25% of the frame or less:

1.    Spot meter the subject and place the tonality. Meter the darkest part of the bear where you want to preserve detail and set the meter to indicate -1 to -1 1/3.
2.    Spot meter the surroundings and open up 1/3 stop. Meter the surroundings. It doesn’t matter what the tonality is. If the surroundings are a medium tone, then set the meter to +1/3. What if the surrounding area is not medium? Just meter it as you normally would and then add 1/3 stop.

Remember we’re just trying to maintain detail in a black subject.

If you’re using matrix metering, chances are you may need about +1/3 stop compensation.

When you have a black or white subject that’s small in the frame, you may want to bracket slightly. Keep careful notes and always bracket in the same way. That is, always use the same sequence. For example, the first frame will be the one the camera suggests as the best exposure. The second frame will be under exposed and the third over exposed. The order doesn’t matter, being consistent does. Once you’ve tried it a few times and analyzed your results, you’ll be better able to set your exposure compensation in the future.

This is a great deal of information to take in without your camera nearby. To get the most out of this post, read it once, then actually go out and try to test the ideas with your camera.

NOTE: Not all camera meters are alike, and few are regularly calibrated per the camera manufacturer’s recommendations. Accordingly, your results may vary from those discussed here, but should be consistent even if off a stop.

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This post sponsored by the Digital SLR Store