Meter this.

We’ve all seen the portrait photographer holding a white-domed object next to the subject’s face to take a light reading. So why is that being done? Why not just let the camera do its automatic exposure thing and take the picture?



 

It’s a good question in this digital age, where we can instantly review our shots to see if we need to re-shoot with a little exposure compensation. After all, the histogram in the camera tells us just about everything we need to know about the exposure in the shot – is it under- or over-exposed and is the exposure evenly distributed over the entire tonal range?

The short answer is that the handheld meter is mostly used to measure the light falling on the subject from studio strobes or flashes mounted off-camera.  In this scenario, the camera doesn’t typically have the ability to control the flash output, as it does in ETTL mode when the flash is mounted on the camera’s hot shoe.  Hence, studio photographers usually work with the camera in manual exposure mode, where they manually set the shutter speed to a value that will synchronize with the flash and the aperture to a value that gives the correct exposure. Alternatively, they can use the  meter reading to set the brightness of each flash in a multi-light setup to give a particular effect while ensuring a proper exposure.

Here, I’ve used the words ‘light falling on the subject’, meaning incident light. Hence, the incident light handheld meter measures the ambient light and ignores how much light the subject is likely to reflect.  The metering system in our camera, on the other hand, does rely on the light reflected from the subject to determine exposure.

Which is more accurate? The incident meter is, because it is calibrated so that it will give camera settings to make an 18% grey card look like 18% grey (middle mark on the histogram) when photographed.  The reflected meter, however, relies on the subject's tone averaging out to 18% grey in order for the exposure to be accurate. If the subject is overly dark or bright (such as a snow scene), the reflected meter gets fooled because it tells the camera to expose as if the subject is mid-grey. The incident meter would read the light falling on the snow rather than the light reflected from it, thereby resulting in the snow looking like bright white snow rather than grey slush.

I started out stating that the incident meter is used in the studio to measure the light from strobes or flashes, but obviously it has a function in outdoor ambient (continuous) light photography as well. Some photographers work in manual exposure mode all the time and therefore rely on an incident meter for camera settings.

So why bother? Part of the answer may be a throwback to the film days, where you never knew until it was developed whether you got the exposure right or not. An incident meter (and a little exposure  bracketing) gave you the confidence that you got the shot. That way of working may still influence the photographer who has made the transition to digital, partly because it’s good practice.

The bottom line, though, is that anyone seriously considering turning pro using studio lighting setups should consider working with a combination flash/continuous incident meter, if for no other reason than to save time. The alternative is to shoot, tweak, shoot and then tweak some more.

Combination meters can be a bit of an investment, so they’re not for everyone.  If you’ve got the spare change, though, a meter can help you understand the exposure mystery a little better and hit the bullseye every time.

Crazy Composite

I've always had this scene in my mind whenever I've heard the song 'Crazy River' by Robbie Robertson, so I decided to build a composite image of my interpretation.

First, I shot an empty field toward sunset. Easy peasy. Because I wanted to give it a Louisiana bayou atmosphere, I figured it needed a big lazy moon. No problem - I had one on a slide. And stars came from a time exposure I shot weeks earlier. A bit of artistic license led to the meteor (or comet if you wish).

Robbie called for an abandoned '59 Chevy. Fat chance finding one of those, so I ordered a scale diecast model for $10 on Ebay. A bit of watercolour paint dabbed on it emulated the rust. To make it look like the car battery had been fiddled with to make the car radio work (so the occupant could listen to Little Willie John), I propped up the hood and lit up a yellow LED on the front seat to make it look like the dash was illuminated. A strobe with a blue filter emulated moonlight along the car's side.

The occupant lying in the back seat had to be created. I've never hired a model and wasn't about to for a personal project, so I was it. With a remote shutter trigger in hand, and side lit by an orange-filtered strobe, I became Robbie's character.

Using lots of layers and layer masks in Photoshop®, I built my composite using the field as a background. A deep blue photo filter layer converted the daylight field to a nighttime field. The masks were used for making the grass appear to be growing around the car and placing the appropriate parts of my body in the back seat. The burn tool added the car's shadow onto the grass. Matching the car to the surroundings was probably the trickiest part, involving a lot of edge smoothing using that layer's mask.

It took many hours to create, but was a great learning experience. One takeaway on big projects like this is to save your work as different (layered) files as you progress, so that you can always go back and rebuild if you really mess up.