Deconstructing light, part two: multiple sources

Part two deals with multiple sources: how and where do you use them? What is the one key rule to remember?

Although you can do a lot with a single flash, there’s even more that can be done with two or more. For starters, you can fill in shadows; or if you want to get more adventurous, you can mix both hard and soft light (direct and diffused) for better definition, or more accurate replication of found light sources. (There’s one particular shot I’m rather fond of that I call ‘the Hollywood’, which I’ll go into later).

There’s one critical thing to remember when using multiple sources, though: there must always be a primary source. If you don’t have one, then you won’t have any subject definition – opposing sources will fill in the shadows, and shadows are what defines the shape of an object.

The same parameters you can control with a single source apply to multiple sources, of course. The more sources you have, the more complicated things get. It’s useful to decompose your thinking thusly:
1. Primary source, on main subject
2. Secondary source, on main subject – definition (rim light, not diffused) or fill (diffused, or reflected)?
3. Other sources, for background objects or secondary subject – take steps 1 and 2 and repeat.

I’m sure you can now see why Joe McNally needs several trunks full of speedlights. I’m not quite there yet, but I find that most of the time a two-light setup is sufficient; there are times where I’ll use three for watches, but I’ve yet to require four sources (except in situations where I need more power from one location, and have to add a second flash to turn the wick up a notch).

Let’s look at some examples.

Ferrari 250 GTO. Sadly, not a real one. Nikon D200

This one has two distinct sources, both flashes behind diffuser panels – one at left, and one at right. They’re actually slightly behind the subject to create a nice specular highlight that defines the curvature in the panels; if I’d put the sources at right angles, you’d have very flat illumination and not much of a feel for the 3-D shape of the car.

Nikon 14-24. Nikon D3

Some objects betray their lighting secrets very clearly – reflective hemispheres are perhaps the worst culprits. For something like this, the best thing to do is keep the light source simple; in this case, two softboxes from the left and right. Power was equal; if not, you wouldn’t get the nice multi-colored reflections off the coatings on the lens. Note that the softboxes were actually pretty close to the subject; the hemispherical shape makes them appear further away.

Lange Datograph. Nikon D700

Through a trick of optical projection, the watch actually appears floating in mid-air and truncated, even though it’s resting securely on the surface behind. Note that this was shot with the lens and watch resting on a flat surface, but lit as though vertical. The primary source was through a diffuser, aimed at the watch and shielded from lighting the lens in front; a secondary source, at reduced power, lit the nameplate of the lens; finally, a third source – again at reduced power – lit the background. A simple-looking shot, but a bugger to light.

Panerai Arktos. Nikon D200

Sometimes you want hard definition; in such cases, a concentrated, direct source is the best way to go, without diffusion. Here, I used one flash from the top, and one from the bottom to provide fill. Both were positioned at a low angle to avoid flat-looking interference at the point of the subject closest to the camera, with a small baffle on one side of the flash preventing light spillage.

Steak. Nikon D700

This example is an instance of when two light sources look like one. A flash with reflective umbrella was used from the top right; you actually need to see a bit of harsh reflection off the oil on the steak to know it’s a juicy steak, making a reflective umbrella ideal. However, you still need to soften out the edges a bit, which is where the very low power secondary source comes in; if it’s too diffuse, you lose the defining effect of the first source, so there’s another flash reflecting off an umbrella from the left, too.

The Hollywood. Nikon D3

There are actually four flashes in play here: two at the back to provide the spotlight effect and backlit definition on the subject’s hair; one from the right in a softbox as the primary source, and a fourth on the D3 to serve as remote commander.

Jaeger-LeCoultre Gyrotourbillon I. Nikon D700

Lighting at the macro scale is extremely tricky – partially because you don’t have a lot of working distance, and partially because your source has to be the right size: too large, and the light is too soft and lacks definition; too small, and you’re going to get harsh reflections and rough-looking surfaces. Here, I used one flash fairly close to the topmost diffuser, with a secondary one through the back diffuser to provide fill of the shadows – thanks to the handy aperture in the watch dial.

Seiko Fifty-five Fathoms. Nikon D700

We finish this section with a classic two-light: primary source upper back center, and secondary fill from the left to give the transparent domed objects – water and watch crystal – some definition. Not much power difference between the two flashes; the bigger difference was the location of the flashes. The back one was further away and with a wider spread than the left one; this created a larger source of almost equal brightness.

Come back tomorrow for part three! MT

A primer on lighting equipment is here. Part one on single sources can be found here.

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