It can be really tempting to chuck light at things. You’ve seen behind the scenes videos on YouTube, and you’ve got some money to burn, so you think “Yeah, if I use 6 lights, my images will look AMAZING”. Now, don’t get me wrong, I own a total of 9 flashes, along with 3 tungsten heads, and assorted other bits and pieces – plus I hire other kit in on jobs if I need it, so I’d be lying if I said there’s never a time and place for lots of light. However, don’t forget that each additional light will bring it’s own 4 characteristics, and these will either help or hinder you. Be aware of the basic principle that the more you add to a shot, the more moving parts you’ve got, the more things can go wrong, the more complex it all becomes, and the more you may find yourself serving and worrying about your equipment, rather than concentrating on getting the shot.
One way to keep a handle on things when you’re using more than one light, or mixing different light sources, is to think of one of your lights as the “key”. This is a term you’ll hear photographers use quite a bit, and it can be very confusing, as rather than refer to a specific light type or source, such as a flash, or a certain modifier like a softbox, it actually refers to the light around which you’re building everything else. A better term might perhaps be “foundation” light, but that’s perhaps not as catchy!
How this works in practice is that if you’ve only got one light, such as daylight, that light is obviously your Key. As soon as you’ve got more than one on the go, it’ll help to keep things clear in your mind if you decide which one of them is the most fundamental, and then adjust the other light around it. With a simple image, like this headshot we’re going to create step-by-step later, the key light is the flash head with the softbox on that’s lighting Lisa’s face. The other 2 lights direction, quality, quantity and colour are all then adjusted in relation to how the light from the key is affecting the subject. Since the light on Lisa’s face is the most important in this shot, it’s natural to make the light with the softbox on the key.
Don’t think though, that whichever light is falling directly on your subject, or the one that’s nearest the camera, should always be the key. The way the 4 characteristics of light interact, in conjunction with the equipment you’ve got to hand, should decide which light is going to be your key. Here are a couple of examples where you may want to choose a less obvious light to use as your key:
If you’re shooting outside in bright sunlight, and using the sun as a light, it’s almost certain to be your key light. The direction it’s coming from, the quantity it gives out, and the quality of it will all dictate not only where and how you shoot, but how you place other lights, how powerful they are and so on. In fact, using the sun as a key light may almost rule out using any other light in some circumstances, as it’s quantity may be so much that the equipment you’ve got with you simply won’t have much visible effect – the built in flash on your camera, for example is unlikely to do too much on a bright sunny day!
Getting ahead of ourselves a bit, if you’re creating an elaborate studio lighting set up, and using modifiers like grids, you may actually have to use one of them as the key – even if they’re not pointing at your subject. The reason for this is the quantity issue – a grid, as we’ll find out later, eats light up, and reduces it’s quantity, so if you want to see the effect in your image, you’ll need to adjust your other lights to suit. This is what I’ve done in this portrait of golfer Chris Wood – the spot of light on the back wall is cast by a light on the floor behind him with a grid attached. This makes it the weakest powered light of the 4 I’m using, so although it’s behind him, I consider it my Key light.
One last example – if you’re mixing light of different colours, but trying to bring the colours into line at the same colour temperature, you can add gels to alter the colour of your lights. Since it can be either impossible, or a huge hassle to gel all the lights in a building – such as this indoor training arena where I shot footballer Peter Crouch, it’s quicker and simpler to gel any smaller lights, like flashes to match the colour of the ambient light. In this respect the colour, and to some extent the quantity of the overhead lights become my Key light – I base the colour and then the power output of the flashes around them, even though the flashes are the lights really lighting my subject.
So, a quick recap – don’t just add loads of different lights for the sake of it, as each light will bring it’s own complications, and when you have more than one light in use, think of one of them as your “key” around which you adjust the others.