Gear skills See the light!
Rod Lawton discovers there’s more than one way to take a light reading
Why would you use a handheld light meter when your Nikon D-SLR has a metering system built in? Because digital SLRs can only measure the light reflected from a subject. Most of the time this works well, but the meter can’t tell the difference between subjects which are intrinsically dark or light. All it sees is the amount of light, and adjusts the exposure accordingly.
We set up two still lifes to show what happens. The camera has no idea that the background behind the bicycle is black, just that there’s not much light. It increases the exposure to compensate, so the background comes out grey. With the shells against a white background, the camera ‘sees’ a lot of light and reduces the exposure, so again the background comes out grey.
Our handheld meter can record the light actually falling on the subject, not just the light it reflects back. This is an ‘incident’ light reading. These are more difficult to measure because you have to place the meter alongside your subject and point it back towards the camera. There are times where this isn’t possible (if the subject is too far away, for example) but in situations like this, it works brilliantly.