Infinity Lighting: How to make your artificial lights look like natural sunlight

There’s always the big debate amongst photographers when it comes to flash vs natural light. With filmmaking, using your own lighting to supplement or override the ambient is the norm. But whether a photographer or filmmaker, how do you make light look like the sun?

The sun is 93 million miles away. This gives it certain characteristics. Lights that are only a few feet away don’t look the same. How can they? Well, in this video, Dedolight introduces us to the concept of Infinity Lighting. This is the illusion of natural light from a far distance.

What’s wrong with artificial light?

All light sources are bound to certain “laws” and restrictions. Regardless of the type of light, whether it’s the sun or a light bulb, they all have to obey the inverse square law, and light always travels in straight lines. This poses problems when you’re trying to shoot larger than your studio or set allows.

This may not be as big an issue in huge studios where you can do all sorts of lighting setups. But for smaller studios and those shooting in small sets, it pops up all the time. Fortunately, there are workarounds to the inverse square law.

Or, well, there are ways to exploit the inverse square law to work in your favour instead of against you!

Light Falloff

Put simply, the inverse square law says that whenever you double the distance between a light source and your subject, you only get to keep a quarter of your light output. So, if you’ve got a light at 1 metre and you move it to 2 metres, you lose two stops. If you move it to 4 metres, you lose another two stops. 8 metres, another two, etc.

This means that when your light is very close to your subject, small distances can show a greater difference in light levels in your scene. This doesn’t happen with the sun. Because it’s 93 million miles away, subjects further back from your subject are lit with pretty much the same level of brightness – even when they’re all different distances from you.

So, for less light falloff and a more even spread throughout your scene, you want your light as far from your subject as possible.

Parallel shadows

Because light always travels in straight lines, when a light is close to a subject, shadows get very large very quickly. This is because the angle of the light source relative to your subject doesn’t allow light to “wrap” around your subject as much.

Again, the sun is 93 million miles away. At that kind of distance, the shadows the light creates are almost parallel. The further you get from the light source, the more parallel they appear.

So, for parallel shadows, you also want your light to be as far from your subject as possible.

How does Infinity Lighting fix it?

Infinity lighting uses mirrors in order to create distance where the distance doesn’t exist. Light continues to obey the inverse square law after it reflects off things. And if you can reflect your light off something, your distance now isn’t just the distance between the light and the subject.

Now, it’s the distance from the light to the mirror and then from the mirror back to the subject. So, instead of lighting your subject directly, you can have your light at the back of the studio, facing towards a mirror at the front of the studio, reflecting the light back towards your subject.

While it might appear that we’re breaking the inverse square law, having the light look as though it’s far away in a smaller space, we’re not. As I said, the inverse square law carries on through reflections. We’re just taking advantage of that fact to create an illusion.

But it’s an illusion that works.

There is a lot more to it than this, and the ~18-minute video covers most of it. it also explains from a maths and physics standpoint, exactly what it is we’re trying to achieve, and how we overcome those limits. And it contains a bunch of very handy tips and tricks for faking natural light in your shots.