Spot-on exposures

Don’t rely on your Nikon’s in-built light meter, Jason Parnell-brookes demonstrates how to use a handheld meter for more accurate results.

How to use a light meter for those tricky-to-expose scenes

Whether you’re in a studio or out on location, before you start shooting you need to dial in your exposure. Your camera has a built-in meter for this, so why do so many photographers buy an expensive handheld meter?

A handheld meter takes an incident reading – it measures the light that falls directly onto the subject. Your Nikon takes a reflective reading, metering the light that bounces off the subject.

It’s a bit like measuring how much water is in a bucket by pouring it into a measuring cup, versus throwing the water at a wall and measuring how much splashes off.

On top of that, your camera is programmed to expose your images to ‘middle grey’. In other words, it wants the reflected light in your picture to have a tonality of 18% grey (see ‘Kodak Moment’, page 40) – and this causes all kinds of exposure problems.

When your frame is filled with a bride in a white wedding dress, a lot of light is reflected at the camera (far more than 18% grey). As such it thinks that your image is far too bright, and tells you to massively underexpose the photograph. When your frame is filled with a groom in a black suit, it tells you to massively overexpose for the exact opposite reason.

An incident meter, by contrast, doesn’t measure reflected light and it doesn’t care what percentage of grey is in the frame; since it only measures the actual light hitting your subject, it always gives an accurate reading – much more so than the built-in option.

It’s a bit like measuring how much water is in a bucket by pouring it into a measuring cup