Photography at its heart is all about light. If you have flat light, you get a flat picture. Flash mounted on the camera’s hot-shoe, unless bounced off a nearby wall is always flat. By taking the flash off the camera and placing it at an angle to the subject you can introduce light and shadow. It is light and shadow that creates a 3D, or ‘modelling’ effect. For example, think of a Rembrandt painting as opposed to an early cartoon drawing.
Off-camera flash allows far more than just controlling light and shade however. It can also be used to create separation between a subject and its background, for example by rim lighting. Another use is to improve contrast.
Portable off-camera flash has been available for years with the humble hot-shoe flash. Advances in technology are now making triggering and controlling that flash more practical. Previously we relied on optical systems utilising pulses of light to trigger and control the flash output. These proved wholly unreliable, particularly in daylight and required line of sight to work. The other option was a simple radio trigger. Whilst these proved reliable, the flash and camera settings had to be controlled manually.
Of the two types of the trigger the simple radio was by far the most useful because of its reliability. However, the slowness of having to manually set flashes doesn’t fit with my quick style of working. Therefore, I tended to reserve it for situations where there was no other choice, such as formal portraits.
A few years ago I was very pleased to learn of a new product by Yongnuo. An inexpensive system that fools the flashgun into thinking it is still sitting on top of a camera. It communicates exposure and other information via a radio transceiver. Essentially for £30 it upgrades any i-TTL flash to support wireless, off-camera flash triggering and maintain full TTL control!
The system will accurately and reliably trigger a flash up to 100 feet away. It even works around corners and inside buildings and syncs at up to 1/8000th of a second. A master unit allows the photographer to support unlimited flashguns in three separate groups. Control is right from the camera, manual or automatic, which speed things up no end.
With additional advances in camera ISO sensitivity, big studio flash systems are not often required. That is, unless I need to overpower the sun. This means I can take a three head system to a wedding that would have required a lighting assistant previously. It makes off-camera flash a viable option in a range of situations it would not have been practical before.
Update: December 2017
I recently invested in the Godox system of flashes, namely the TT685 and the AD200. Both of these units do everything the Youngnuo transceivers do, but have distinct advantages. Both systems are complete packages, containing both flash and radio receiving unit. This makes them easier to deploy with less kit to carry and assemble. At £86 for the TT685, they also represent excellent value!
The Godox AD200 is a unique offering, only a little larger than a standard Hot-shoe flash, it is 3 times as powerful. It has been designed to be used purely for off-camera work and does not even feature a hot-shoe.
The AD200 comes into its own when shooting outdoors and you need more power. Previously I had to mount three transceivers on to a 3-way bracket, then three flashguns then set them all to the same channel. It was unwieldy and so had to broken down and setup between locations. That took time. The AD200 is one unit, screw it into the bracket, add your light modifier and you are good to go! Its’ also sturdy enough to leave on the stand between locations and can be transported by hand in a ready to shoot state.
Whilst the flashes and triggers provide the quantity and ease of calling for light, its qualities are determined by the light modifiers in use. Note I write qualities, rather than quality, more accurately I should write ‘properties’.
There are a bewildering array of light modifiers available but at their heart, they control a different mix of several properties. These are softness, spread and specular highlights.
Soft Vs Hard light
Hard light is defined by a hard ‘edge’ between the light and any shadow it creates. If it has a clearly defined outline it is hard light, if the shadow is less defined and more graduated, perhaps not present at all it is soft light.
Like many photographers, I learned my trade with the firm belief for portraits, the softer the better. Over the years I’ve learned this is inaccurate. Light isn’t either completely hard or soft, it is on a sliding scale. That scale of softness is determined primarily by the size of the light modifier and its distance from the subject. This, in turn, controls its size relative to the subject. The larger it is (relative to the subject) the softer it is. This is important because it means you can control its softness by changing its distance.
A larger modifier gives you a softer light at any given distance. More importantly, a larger light modifier provides a greater working distance.
Another thing different types of light modifier control are the spread of light. That is, how much the light spreads out or is focussed. Some types of light modifier spread light over a wider areas than others. Sometimes you need to spread a light, other times you want to control it.
A standard brolly is a great modifier when you want to spread light evenly over a large area, for example when shooting groups at a wedding, two 42″ brollies can cover a wide area. A softbox diffuses the light through an additional diffusion panel to make it softer. It is also better able to limit its spread, particularly if a grid is used.
There are all kinds of modifier available which control spread, from 360 degree diffusers made to throw light in all directions to the snoot designed to limit it to a few degrees. There is no right and wrong answer on which to use, it all depends on your working methods, situation and what you are trying to achieve.
In this example I used a 42″ brolly to quickly throw some light into a dark corner where the brides friend was getting ready.
In this example I had to hide a flash on a ledge to balance indoor light with outdoor light. A classic example of where off-camera flash using small lights is ideal.
Specular highlights refer to how much ‘sparkle’ the lighting has on the subject. Silver and other highly reflective light modifiers produce more specular highlights. Light modifiers that have white surfaces, particularly when multiple layers of diffusion are used tend to have less.
One specular highlight they all share is the ‘catchlight’ in the subjects eye. There tends to be a preference for octagonal cachlights at present.
Which Light Modifier to use for Off-Camera Flash
The short answer is, it depends. It depends on what you are trying to achieve, what and where you are shooting.
For example if I want the absolute softest light possible and to be able to control the spread of light then a softbox with grid is perfect. If you want to spread light around quickly an umbrella is a good choice. What if you want to create more light and shadow to enhance he modelling effect on the subject? A beauty dish is often a good choice here, with or without a diffusion sock.
Then comes to what, or who you are shooting. Older subjects with fine lines generally look better with a softer light source to smooth out those lines. Conversely, younger subjects often look better with a harder light source. While a softbox hides fine lines, a beauty dish makes for an edgier more contemporary portrait.
Finally we come to where you are shooting. Indoors at a static location the 1.5m softbox or a large umbrella may be the perfect solution. Take that outside into even the gentlest of breezes and it will catch the wind like a sail. In those circumstances it is far better to use a smaller light source and use the ‘size relative to the subject’ rule and get in close.
I am a big fan of softboxes for studio work, brollies for large areas at weddings and a beauty dish for outdoors.
Summary of Off-Camera Flash
Off-Camera flash is a useful tool in any photographers kitbag. It allows you to throw light, in a pleasant way, where otherwise there would not be enough. More importantly however, it can be used to improve the quality of available light.
Advances in technology have made off-camera flash not only more accessible, but more practical. Portable systems that can be comfortably carried by one person are now available.
Light modifiers are what change the properties of the light generated by the off-camera flash. Its important to experiment and find what works for your style of photography.