Lighting an image step by step

So, before we head into the studio, let me take you through a useful exercise I taught at a photography college recently. We’re going to light a portrait shot step by step, starting from an automatic exposure straight from the camera, then adding on camera flash with a flashgun, progressing to moving the flash off-camera, and eventually adding extra lights to create more depth. We’ll be bringing together a lot of what we’ve learnt, and applying it in a practical way.

The room we’ve used is a lecture room at Ravensbourne college, and the ambient light is coming from some fluorescent tubes in the ceiling, and a touch of daylight from the windows across the room. The camera is a Nikon D800, mounted on a tripod with a 24-120mm f4 lens on the front, and we’ll be adding light from 3 flashguns: an SB700, an SB800, and SB80DX and finally an Elinchrom 500 watt/s flash head. We’re using several different types of flash to illustrate the point that lighting is not dependent on having the latest and greatest kit – some of these flashguns are 14 years old – and that the principles of light are the same if you’re using the ambient light, a flashgun, or a more powerful flash head.

We’ll also be using some Pocket Wizard Flex TT5 radio triggers, a couple of lighting stands, some coloured gels, an umbrella, some adapters to fit the flashguns onto the stands, some velcro straps for the flashguns, and some bits of corrugated black plastic to act as baffles.

Here’s the shot we’re trying to get close to – a portrait of pro cyclist Alex Dowsett taken at the Olympic Velodrome in April 2015 for Men’s Fitness magazine:

And here’s our first shot, taken with the camera on a tripod, on Aperture priority exposure mode with just the ambient light in the room (Matt the lecturer is our model, notably not wearing a helmet or a skin-tight cycling suit….)

Shot 1: Exposure 1/2s @ f5.6 ISO 100 – no flash.

Note the blur around the eyes caused by the slight movement of the model during the 1/2 second shutter speed – the camera was on a tripod, so we know it’s not the camera that moved. With this shot the camera has tried to get a correctly exposed shot under the ambient lighting conditions.

For each stage, I’ll show you the lighting setup, and this one’s pretty simple:

Just so you’re familiar with this – we’ll be seeing it a lot – there’s the camera at the bottom, Matt is the green shape in the middle, and the back wall is represented by the funny box thing! Now let’s add a flashgun to the hotshoe on the camera:

Shot 2: Exposure: 1/60s @ f5.6 ISO 100

The flash is set to TTL auto mode, and since the camera is still on auto mode, the camera has chosen the best exposure for the flash, based on the light bouncing back from the subject. This means the exposure for Matt is OK, but the wall 8 feet or so behind him is very dark. Also, the angle of the flash directly on top of the camera means the light isn’t very flattering, and a long way from where we want to be. Here’s the setup shot:

Next we’ll switch to manual exposure mode, and open up the shutter speed to allow more of the ambient light in:

Shot 3: Exposure: 1/8s @ f5.6 ISO 100

Slowing down the shutter speed has allowed more of the ambient light into the shot, lightening the background, whilst keeping Matt lit with primarily the flash. Since all we’ve done is change the exposure, the setup shot is essentially the same.

Now let’s switch the flash to manual power mode, so that we can be in control of how much light it puts out, and let’s take the flash off-camera, to mimic the light of the shot we’re working towards. In order to trigger the flash whilst it’s off camera we’ll need either:

  • A dedicated cable. Expensive, but allows for auto exposures. Not great to mount on stands though!
  • A basic cable. Much cheaper, but only permits triggering, no control of output on the flash.
  • A wireless trigger. Expensive, but allows us to work without wires, and with some models also permits control of flash power too.

Whichever of these we use, we’ll need some sort of mount in order to be able to attach the flashgun (and possible modifiers) to a stand. So we take a lighting stand, and an adapter, then add a radio trigger to the camera and the flash and place the flash off to camera left, about 4 feet from Matt:

There’s the flash, off to the left, now here’s the image:

Shot 4: Exposure: 1/8s @ f5.6 ISO 100

The biggest change here is the shadow across Matt’s face – the light is now clearly coming from one side rather than straight on. The lighting is quite harsh though, and we know from looking at the image of Alex that we’re trying to create a softer light, so let’s add an umbrella to the flash, and let’s crop a bit closer in to better mimic the pose in the original image:

Shot 5: Exposure: 1/8s @f5.6 ISO 100 White Balance switched to Flash from Daylight, as we’re about to light with just flash.

Here we can see how the light has been softened by the umbrella (or brolly). The shadows on Matt’s face are a bit more subtle, and their edges have softened. The setup is pretty straightforward:

Now, we want to start adding more depth to the image by bringing in other lights. Looking at the original image, we can see there’s a light at the back aiming across Alex’s shoulder, and there’s some light on the background too. If we use flashes to do this job (rather than relying on ambient light alone) we can shoot at a much faster shutter speed, which will help us to remove any movement on the part of the model, or camera shake if we weren’t on a tripod. So let’s push the shutter speed to the maximum sync speed and see what happens when we exclude the ambient light:

Shot 6: Exposure: 1/250s @ f4.5 (opened up to get the flash exposure brighter) ISO 100

At 1/250s shutter speed, very little ambient light shows up, and we’re only really using the flash to light with. I’ve opened up the exposure by 2/3 of a stop, to account for the fact that there’s no longer any ambient light on Matt – up to now the exposure has been a bit of a mix. The flash is still in its brolly off to the left, although we’ve moved it very slightly more to the side of Matt to throw half his face into shade. Now we’ve excluded the ambient light, we can consider this flash our “key” light – it’s the light around which we’re basing everything else. Any other light we include we’ll need to think about how they work in relation to this light – where their shadows are cast, how powerful they are, and so on. Go back and have a quick look at the original image – we’re getting much closer, but need to add more light. So let’s add a 2nd light at the back of the shot to throw a highlight onto Matt’s shoulder:

Shot 7: Exposure: 1/250s f4.5 ISO 100

What we’ve done here is place a 2nd flashgun back and right (from the camera’s point of view) aimed back at Matt. The flashgun is a Nikon Sb800 set to what’s called SU-4 mode – a fancy way of saying it’s using a basic optical slave. Recall what we learnt about flash triggering, and you’ll realise that this means we can trigger this 2nd light, as it will respond to the light from our key light, but we can’t do any more. We can’t adjust power output for example. The 2nd flash we’ve just added is also on manual mode, and has a little velcro strap on it, with a piece of black plastic attached to keep the light from spilling into the camera. This can be very important when you have lights that are aimed towards the lens, as otherwise you can get what’s called flare:

Shot 8: Exposure: 1/250s @ f4.5 ISO 100

Here we’ve moved the back light right in line with the camera, and created too much “flare”. Flare refers to “non image-forming light”, and whilst it’s very fashionable to use it nowadays, be careful. You can see how the flare has taken all the depth out of the shadows on the side of Matt’s face – reducing the contrast we worked so hard to create by moving the brolly round. Flare can look great, but use it sparingly, and be aware that the smallest movement of your camera in relation to any light in the back of the shot can have a massive effect on how much flare you see. Let’s put the back light back to where it should be, and add a 3rd light to lift the back wall:

Shot 9: Exposure: 1/250s @ f4.5 ISO 100

We’ve now added a 3rd flashgun to the back right of the photo, again on SU-4 mode, mounted on a small foot to allow it stand upright, and then balanced it carefully on a stack of desks aimed at the back wall. This has cast a shadow from another desk in front of the flash, and obviously made the back wall much brighter. The application of inverse square law (the power of light falls off inversely proportional to the distance from the light source) means that even though the back wall is only 8 feet or so behind Matt, the fact that the first light we used with the brolly is only 4 feet from him allows us to light it separately as it’s much darker than Matt. You can’t escape an aspect of physics like inverse square law, but you can take advantage of it, allowing you to create depth and light on different planes, even in a fairly small space like this. Now, to make our shot look a bit more like the pic of Alex, let’s add some colour to the back light by putting a gel on the light we’ve just added:

Shot 10: Exposure: 1/250s @ f4.5 ISO 100

We’ve already covered gels when we talked about modifiers, but here’s a very quick recap. A gel is a cheap piece of flexible, transparent coloured plastic that can be placed on the front of a light to change its colour. There are “official” gels that are used to correct for different colour temperatures, and there are effects gels such as deep reds or purples for when you just want to create some bright colours. In this case we have used an orange gel, or more precisely a “Full CTO” – full Colour Temperature Orange – which is a correction gel, but we’re using it to create a deliberate colour cast. You can also see where the flash is aimed, and how the light falls off – the right hand edge of the background is much brighter than the left. This is inverse square law in action again, and in this case it suits our purposes as we don’t want the whole back wall to be uniform in colour. If you were trying to create an even tone you’d need to either diffuse your background light much more, or place it further away from the wall. Now to finish things off, let’s add a second colour to the back wall using our 4th light:

Shot 11: Exposure: 1/250s @ f4.5 ISO 100

To finish, we’ve added a 4th light in the form of an Elinchrom 500 w/s mains powered head, fitted with a basic reflector on the front, and with a piece of purple gel over the front. It’s aimed at the back left of the wall, and the colour has been allowed to blend and merge with the yellow/orange from the 3rd light we added. Although the Elinchrom is a large, studio, mains powered unit, and thus far we’ve only been using small, battery powered flashguns, they’re all perfectly compatible. The Elinchrom also has an optical slave, so we simply set it to use that, and adjust its power output to bring it in line with what the flashes are putting out.

We’re all done here, let’s have a quick recap, and look at a before and after:

A quick run through of what we did to get there:

  • Took the camera off auto exposure mode to give us control over the exposure
  • Moved the flash off camera to allow us to control where the light falls
  • Triggered the off-camera flash via a radio trigger
  • Set the flash to manual mode, to keep exposures consistent from frame to frame
  • Added an umbrella to our key light to diffuse the light
  • Added a 2nd flash to sculpt highlights on the shoulder and face.
  • Triggered the 2nd flash (and 3rd and 4th) via optical slaves
  • Placed the 2nd flash carefully to limit the amount of flare coming into the camera
  • Added a 3rd flash, with an orange gel on, washing across the back wall
  • Added a 4th flash, this time a large, mains powered unit, with a purple gel on, to wash across the wall from the opposite side.

All we’ve done is apply the basic rules of lighting (Direction, Quality, Quantity, and Colour) using a mix of simple, affordable kit and more expensive studio equipment. We obviously can’t completely recreate the image of Alex we started with, as we’re not shooting in the Olympic Velodrome, and that image has had some photoshop work done on it too! We could also work much quicker if we weren’t stopping at each stage to explain the process – I regularly create shots like this in 5 minutes or less, and so can you with practice!

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