Matrix Metering with Digital
About 18 months ago, I wrote about the problems that come with matrix metering. By evaluating multiple segments of a scene and making exposure decisions for you, matrix steals a degree of control from you. You never really know just how smart it is, what it has taken into account or what it thinks is important. Thus, I've always greatly preferred spot metering.
Well, it's time to modify my stance a bit.
I've been shooting digital for some time now and slowly but steadily it has changed my thinking on things. Digital gives me the histogram. Now I can see the results of the decisions made by matrix metering and compensate accordingly, while still on location. And in near real time.
Spot metering multiple points in a scene still works best, but it can be a lengthy process. In tricky lighting conditions, things can change quickly and it can be hard to react in time. Occasionally, I've given matrix metering a try and have evolved a means of using it as a tool, while still retain control myself.
With matrix metering, I simply meter the scene and set the aperture and shutter speed to center the meter. I still work in manual exposure mode so I can change both independently. I take a "test shot" and check the histogram, using it to then adjust the exposure as needed and shoot again. It doesn't matter what the meter ends up reading; it's just a measure of how much my evaluation of the scene differs from what matrix metering thinks. Much better than blindly guessing if any exposure compensation is needed. As the light changes, all I have to do keep the meter reading at this point, and I have thereby kept the overall exposure where I want it.
As an example, let's assume that the sun is starting to rise. I've already composed my shot and set the camera on my tripod so what matrix metering will see won't change. By utilizing the histogram, suppose I've determined that the meter needs to be set on one stop under to get what I want. As the sun continues to rise, things will get brighter, forcing me to shorten the shutter speed to keep the meter at minus one. The resulting shot though, often continues to give me what I want, all with only the single meter reading. If the lighting changes drastically, I may find I need to start setting the meter only half a stop under (or whatever) to keep the exposure good, but this is easy to adjust. This makes for a quick way to work that retains a high degree of control when time is of the essence.
When I have time to, I still prefer spot metering, but my stance on matrix has softened to an extent. Digital does that. If you're now shooting digital too, you may have also caught yourself rethinking some of the things you used to accept as given about photography. If not, it might be time to start.