I recently had the good fortune of attending a lecture on landscape photography by Tom Mackie. He has published a couple of books with some splendid photographs. In both of these, he is of the opinion that film is better than digital. I was pleasantly surprised when he said during the lecture that he now uses a Canon EOS 5D Mk II and that he finds the results comparable to film, if not better. While digital and film photography are similar in many respects, there are things that are possible with each that are not easily replicated with the other. With film, you would expect to expose correctly for the main subject. You would do the same with digital, especially if you were shooting jpg.

Shooting raw, however, offers an interesting opportunity. The way data is represented in binary means that the brighter parts of the raw file are capable of holding much more information than the darker parts. Also, for a given exposure, the noise level would remain relatively the same. This gives one the opportunity to expose the image as far to the right of the histogram as possible without actually clipping the highlights. The idea is to pull back the exposure during raw conversion to preserve detail in the shadows and drive down the noise, thereby improving the SnR (Signal to Noise ratio).

Quick & Dirty Factoid: Exposure time in seconds at ISO 6400 is equal to exposure time in minutes at ISO 100. You can use this to get a ballpark exposure in low light without having to wait for minutes during which the scene migh have changed and you might have lost the shot.

When shooting digital, do you really need a lightmeter, especially when exposing to the right? Well, yes and know. The first thing is to use a method you are comfortable with. However, it may be worth pushing out of your comfort zone at times. I generally prefer to use the camera’s metering system to get a decent idea of the exposure and then look at the histogram. The idea is to get as much information as possible to fit within the limits of the histogram. An RGB histogram is useful in that it helps you to avoid clipping individual channels and avoid colour shifts.

However, there are situations where this doesn’t work well. Consider a scenario where you have had to underexpose to fit everything within the limits of the histogram. So, you might have well prevented the clouds from blowing out, but what about your model in the foreground, who might end up grossly underexposed? Sure, you can bring up the tones during raw conversion, but you also then bring up the noise. Which was exactly what you were trying to avoid by exposing to the right. So, you need to make a tactical decision at this point. Expose for your main subject and let the highlights go. Use graduated filters or HDR if you want.

So, when is a lightmeter useful?

1. You can use it to get an initial correct exposure as a point of reference and then expose the rest to the right.
2. Setting up lighting ratios in a studio setting.
3. Shooting jpeg or to speed up your workflow when you don’t have the time to individually adjust hundreds of images.

Technology always evolves with time and so will this workflow.