Welcome back to Introduction to Flash Photography. In this lesson, we're going to be talking about the qualities of light. Now, one of the most important things to know is that not all light is created equal!
For our purposes, we're going to say that light has four qualities that we want to be aware of, and that we want to learn how to control. These four qualities of light are:
- the intensity
- the colour of the light
- the direction of the light
- the texture of the light
In this lesson we'll cover each of these qualities individually and how they affect your images and what you can do to control each of them.
Intensity of Light
Intensity is really just a measure of how much light is hitting our subject and reflecting back to our camera.
We can control the intensity of the light we're using and a couple of ways. The first of which is to turn the power up or down on our flash. Most flash units have the ability to greatly vary the amount of power released in each flash. On my flash it's as simple as turning this dial.
As you see the numbers changing different fractions are giving us different power settings. Most flashes display power as a fraction of the maximum power that that flash is capable of. 1/1 being full power all the way down to 1/128 for this flash.
Now the other way to change the intensity of is to move your light source closer or further away from the subject. As light travels away from a light source, it dissipates, following the inverse square law:
In practice, what that means is that light loses its power at a constant rate as it gets further away from a subject, and we can calculate that. "Inversely proportional to the square of the distance of that object from the light source" means that each time you double the distance, your available light drops in intensity to one-quarter of the intensity at the previous distance.
For example, imagine that you have a flash that is one meter away from your subject. You set your power for that and you get a great picture, a perfect exposure. If you then move your flash to two meters away, you might imagine that you would have to double the power output of your flash to achieve the same light intensity, but that would be wrong, because you would actually need to square the light output. That means you would need to quadruple the power of your flash to make up the difference. And if you move your flash to 4 meters away, that would be 16 times the power. 8 meters would be 64 times the power.
So when you're using small flashes of limited power, it's very important to be able to get your flashes as close as possible to your subject.
The next quality of light that we want to get control of is the colour of light or the white balance. Our eyes and brains do quite a good job of balancing the different colours of light we see in our world, but our cameras and flashes on the other hand are not quite so smart, and they need our help to get them along.
The main way that we speak about the colour of light is by the temperature of the light. We say that warm light is yellow and that cool light is blue. Now we can adjust the white balance setting on our camera to compensate for the different colours of light that we photograph with natural light. Or if we're shooting RAW, we can make this adjustment in Lightroom.
Next, we want to talk about the direction of the light. The direction that light hits our subject can have a huge effect on the feel of the images we're taking. Here's just a quick example of how the direction of light can affect a photograph. I have taken several photos of myself with a single 42-inch umbrella to show you how much of a difference the direction of light can make in a photograph.
In this first photo here I have what I would call my standard lighting. The umbrella is 45 degrees to the side of me and 45 degrees up from me. When we crop it a little bit closer, you can see that this gives us a simple, flattering light.
This is basically how we set up my lighting for videos. This is definitely a great go-to all around useful position to light from. However, if we want to create a little drama, all we have to do is move our light a few inches around to my left.
Now, as you can see, the umbrella is about 60 degrees off centre from my face. This is what is known as Rembrandt lighting. Now the easiest way to recognize Rembrandt lighting is to look at this little triangle area of light, right under the eye that's opposite of your main light source.
I love lighting like this, and I think it creates a very classic and a very regal kind of look and it gives us a timeless feel to our portraits. In this next photo, the umbrella has been moved to just about 90 degrees, or perpendicular, to my face. This is what's called split lighting.
And as you can see, it adds a lot of drama to this self portrait.
But if that's not quite enough drama for you, we can go even further into what is called profile lighting. In this photo, we see that the umbrella is just a little bit past our subject and is aimed back towards the camera ever so slightly.
Of course, now the subject is also turned away from the camera at 90 degrees. I love using this kind of light whenever I can. I think it brings out so much gravitas to your image and it makes your subject feel very pensive and very thoughtful.
As you can see the direction of light gives you a ton of freedom to be creative in your photography. Especially when it comes to defining the moods and the emotions that are present in your photos.
Finally, we're going to be talking about the texture of light. When we talk about texture, we use words like hard or soft light or direct or diffuse light. The way I like to think about it is that hard light creates hard shadows and soft light creates soft shadows. The other way to think about it is that direct light comes from a relatively small light source and diffuse light comes from a relatively large light source.
Here's what I mean by relatively: the sun is a light source that is 110 times larger than then the earth. But because it's so very far away, it appears as a very small light. On the other hand, a 42 inch umbrella is very small in comparison to the sun, but when you place it two feet away from your subject, it appears much larger. And therefore it gives us much softer light. So it's not just the size of your light, but it's the apparent size in relation to your subject. I think it'll be easier to show you what I mean by soft and hard light, rather than try to describe it with words.
Here's an example of what I would call pretty soft light:
It's definitely a softer light compared to this image:
Now these are basically the same image taken with the same flash. Only in the first image we have bare bulb flash and in the second image, we have the same flash with a 42 inch umbrella. For me the easiest way to think about the difference between hard and soft light is the transition from full shadow, into full light.
Now, as you can see in this area right here, the shadows are all the way dark.
And if you were a little bug sitting back here and you were against the background, you would not be able to see the light source at all. But as you began to walk this direction, you'd get into this murky area. And this is what's called the penumbra.
When you're in the penumbra looking back at the light source, you would see part of it, but not all of it. In fact, you'd see just a tiny part of it right here. And as you walked further and further out away from full shadow, you would see more and more and more of the light source until you got into full light. Once you're in full light, you would be able to see the entire light source.
Now it makes sense that a big light or a large light source would take you longer to walk along to see more of the light, and thus you would get this soft area, or this gray area. Whereas when we look at this image, we have a very small light, and you can imagine as a little bug, you'd be standing right here, and you would just take a few steps you would go from not being able to see the flash at all, to you could just peek your head out and see the entire flash all at once.
This is what we would call hard light. And if we zoom in really close, you'll see that there's still a little bit of a penumbra there. There's still a little transition, but it's very small when we compare it to this image.
The other thing that's important to know is that the distance away from the subject that your large light source is also affects the softness. Notice how in the image that we've been using here, the flash is about 10 feet away from our subject's face and producing a pretty soft image. But in the other image, we actually moved the flash to where it's about a foot and a half away from the subject. And what it does is it provides a very, very soft light.
In fact, it's so soft that if you were a bug on the background here, you would not be able to find a place to hide in full shadow where you could not see the light because of this large light source. It's actually wrapping all around the subject and down the back.
So when it comes right down to it, controlling your flash means controlling just these four aspects of light. And once you break it down to these simple building blocks, I think it makes it much easier to get the results that you want from your flashes.
Now, I know you can get a grasp on these four things and over the next few lessons, we'll kind of get even more in depth on how to control these four aspects. And I know that this is going to take some of the magic and the voodoo out of flash and make it very simple. It really is just building blocks that you put together to create the image that you want.
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