Off-camera flash can seriously enhance your photos. With the right technique, you’ll be able to capture stunning images in no time. In this article, we share with you everything you need to know about how to use off-camera flash. Whether you’re using it for portraits, product photography, or anything else for that matter, this guide is sure to guide you to becoming an expert photographer!
Off-Camera Flash: The Basics
There are a couple of basic things to understand before we delve further into the techniques of the off-camera flash. Off-camera flash, as the name suggests is the technique of taking your external Speedlight/flash unit and mounting it off-camera. This results in the light falling on the subject at an angle, rather than straight on.
The second thing to understand is that the off-camera flash needs to fire in sync with the camera shutter release. That means there needs to be a connection between the off-camera flash and the camera, triggering the flash on demand. There are a number of different ways to fire the off-camera flash.
Related Article: What Is A Speed Light & Why You May Need One
Advantages of Using Off-Camera Flash
There are many advantages to using off-camera flash. Let’s take a look at a few of them.
1. Better Full Body Images
One of the key advantages of using an off-camera flash is that you can position the light in a more suitable manner so that you can capture better full-body images. Off-camera lights can help you overcome the problem of light fall off when you try to shoot full-body portraits using an on-camera flash. Let’s elaborate on how that happens. But before that, we need to understand an important aspect of light – light fall-off and the Inverse Square Law.
Light Fall Off
With a flash mounted on your camera, you would be handicapped by the Inverse Square Law which determines the amount of light fall off. We all know that increasing the distance between the subject and the source of light decreases the amount of light. But the question is how much would that fall-off be?
A Word on the Inverse Square Law
The Inverse Square Law is something that gives nightmares to even professionals. Needless to say, amateurs find that intimidating, to say the least. But there is a process and once you grasp it this is as simple as water.
To make it easy, let’s look at a scenario.
Let’s say that your subject is standing 3-feet away. At 2-foot the amount of light falling on the subject warrants an aperture of f/11. This is purely hypothetical. We are just taking some numbers to explain the concept. Now, let’s say that the subject moves away to a distance of 4-feet from the light source. So, the distance essentially doubles. But by doing that as per the equation of the Inverse Square Law, the amount of light fall-off means that the subject now receives only 1/4 of the amount of light that it was receiving previously (when it was at 2-foot). How did I arrive at that?
Well, I took the additional distance by which the subject moved away from the light source, then squared it and then inverted it. Voila, that gives the amount of light now reaching the subject. The result is 1/4. Or, in other words, the subject now gets only 25% of the light that it used to get.
The final effect of this is I will have to open up my aperture in order to compensate for the loss in light. By two stops precisely. Because every full stop of aperture results in doubling or halving the amount of light. Moving from f/11 to f/8 will double the light and make it 50% (I was receiving 25% to start off). And moving from f/8 to f/5.6 will again double the amount of light making it 100%.
Full Body Images With off-camera Flash
Now coming back to the question of full-body images with off-camera flash. With an off-camera flash, you now have the option to use any lens you wish to for making full-body portraits. Normally, when a photographer shoots full-body portraits a telephoto zoom lens such as a 70-200mm is used. This allows the photographer to capture the body proportions correctly. But with an on-camera flash, you can’t really move too far away. This because the light fall-off is significant. You will have to dial up the ISO in order to get better exposure if you are too far away.
Additionally, the light is fired straight on. Which is not great, to say the least. We will discuss this problem later.
Now with the ability to light from any angle, you have the option to place the light closer to the subject and get a beautifully exposed image despite using a long lens and standing much further away from the subject.
The off-camera flash setup allows you to use multiple lights and so you have the option to use one as your key light and the second as your fill light. You can go on adding additional lights. The creative freedom is boundless. We shall discuss a few off-camera flash lighting examples later in this discussion.
Plus, with a telephoto lens, you also have the option to blur out the background. Because in order to fill in the frame with a subject you will need to take a few steps back and then zoom in slightly to tighten the composition. Leave enough distance between the subject and the background and you will get a nice bokeh.
Related Article: 7 Tips for Better Indoor Portrait Photography
2. Create a Lighting That’s More Flattering
Another major advantage of using off-camera flash is to produce lighting that is a lot more flattering. For example, with an on-camera flash, the direction of the light is always straight on. With an off-camera flash, you have the option to set the angle of the incident light according to the style of the image that you have envisioned. For example, directional light produces depth in an image. Something that looks beautiful in the final product. You can use multiple lights and vary the ratio of power between them to create specific looks.
Most importantly, with the know-how to use off-camera flash more than one flash unit can be used in sync to produce stunning images in less than optimum lighting conditions.
3. Have More Choice in Diffusers and Modifiers
An important tool in the hands of portrait photographers is light modifiers. When I say light modifiers what I mean is the whole range of tools that help modify light, shape it, change it, and make it conducive to a shoot. The majority of flash modifiers can only be used on off-camera flashes.
Softboxes are a great way to change the nature of the light. A single flash is a small light source and therefore categorized as hard light. With a softbox, you can convert that hard light into a soft wrapping light perfect for portraits, product photos, and other related types of photos.
Related Article: Getting Started in Off-Camera Lighting With softboxes
Hard Light is any light source that is small in comparison to the subject being photographed. Smallness or largeness is a relative though. So, while the Sun is a huge ball of fire and gasses is considered as a source of hard light because it is millions of miles away and is thus ‘small’ when compared to a human face. Another characteristic of hard light is that it will produce dark shadows.
Soft Light, on the other hand, is a source of light that is larger when compared to the subject being photographed. Amusingly, a flash with a diffuser on is considered as a soft light, because the light itself is large when compared to a human face.
You can convert a hard light into soft light and soft light into a hard light using modifiers. A large white sheet or a white curtain can make the hard light of the midday sun softer. In the same way, if you push your flash mounted on a light stand further away from your subject it becomes hard light.
In photography, both hard light and soft light have their own advantages and disadvantages.
How to Use Off-Camera Flash Combined with Natural Light
The art of mixing off-camera flash and natural light usually produces stunning images. Natural light alone can contribute to beautiful results. Natural light is your single source of unlimited stunning images. But the problem with natural light is that it does not stay the same throughout the day. It keeps on changing as the day goes on. By that I mean it can become hard or soft during different times of the day. And with that, the color temperature also changes. Therein lies the problem. With the changing light, you have to keep adjusting to it. If you are primarily a natural light shooter you have to adjust the color temperature and also the exposure. This is why professionals tend to mix natural and artificial light to somewhat equalize the changes. The know-how to use off-camera flash combined with natural light can take your photography to the next level.
Related Article: Using Color Gels When Working With Flash
How to Use Off-Camera Flash During the Golden Hour
This is probably the most common and easy to use the time to mix artificial lights with natural light. It is great for when you are shooting portraits outdoors. Keep the sun behind the subject and fire your off-camera flash from in front of the subject. Here your flash is your primary light or the key light illuminating the subject.
The natural light works as the rim lighting and for producing a hair light. Exposing for the background is the best solution in this situation because that produces a naturally saturated and contrasty look. Usually, the sun is never captured in the frame.
How to Use Off-Camera Flash During Blue Hours
I personally prefer blue hours to golden hours because I love the cool blue sky that creates a perfect contrast to a warmly lit face. But that does not mean I wait until it is completely blue. I still prefer that tiny hint of warmness in the western sky just before it is completely blue to make my blue hour portraits.
And to achieve something like this it is imperative that you know how to use off-camera flash as well as how to expose correctly.
The first thing is to understand what to expose for. Remember, if you expose for the face the background will appear darker. You need the faint light in the scene to be captured in the final image. So, exposing for the background is key here. To do this, first meter for the background. Then dial in the exposure settings manually. After that focus on the subject’s face. If your camera has eye-focus, by all means, use that.
The next thing is to set up your flash. I prefer to setup up my flash manually. Using the slave mode. Depending on the distance of the light from the subject I would use ½ power and then adjust depending on the result. Note that the light from your flash should be used to expose the face and make it just bright enough compared to the rest of the scene.
How to Use Off-Camera Flash to Produce Soft Light
One of the major advantages of using off-camera flash is that you can change the look of your images very easily. Something that is impossible with an on-camera flash. For example, if you are shooting inside a room with white ceilings and or walls you can use a technique known as bounce flash to produce a softer light.
For this technique, you need a flash unit and a white ceiling and/or a wall. The technique of bounce flash requires the flash to be fired at the ceiling or the wall.
Another easy way to produce soft light is to move the light source as close to the subject as possible. Thereby enlarging the light source in relation to the subject. When that happens the light wraps the subject from all sides and produces effectively what is known as soft light.
Ways to Fire an Off-Camera Flash
Using a PC Sync Cable
A necessary step before you understand how to use off-camera flash is to understand the different ways you can make a connection between your camera and the off-camera flash. The easiest process is definitely to use a PC sync cable. These cables come by default along with your flash. All you need is to plug one end to your camera and the other end to your flash.
Using the Slave Mode on Your Flash
Every flash unit comes with a slave mode. I am referring to the optical slave mode. In this mode the flash unit will fire instantaneously as soon as it detects a pulse of light. The idea is to use the built-in DSLR flash or a second flash unit mounted on your camera and use that flash to send out a pulse of light to the off-camera flash. Please note that the master flash, which is the one that triggers the off-camera slave flash, is powered down to its minimum output. This is to ensure that it does not influence the exposure at all. This is the setup that I personally would use when shooting outdoor portraits in the blue hour.
Using Radio Triggers to Fire Off-Camera Flash
The most trusted process to fire an off-camera reliably is to use radio triggers. Yes, optical triggers too can work but they don’t use TTL metering and therefore there is no way to pass on the exposure information to the flash. Neither can you control the flash power. Additionally, when you use multiple off-camera flashes things can get complicated very quickly. In such situations, the solution is in using a camera flash trigger that uses radio technology.
Radio triggers come in pairs. They can work as receivers and transmitters interchangeably. You need at least a pair to work with a single camera single flash setup. One of the transceivers will mount on your camera and assume the role of the transmitter and the other transceiver will mount on your light stand with the light mounted on it. This will assume the role of the receiver.
Both transceivers must be on the same channel to communicate with each other. Some off-camera flash manufacturers come with their own wireless flash triggers and you could optionally use one of these. The idea is to be able to control the flash remotely.
With radio triggers, you can use a setup constituting multiple flashes and have them fire in unison and control them individually from a distance.