How to build your own realistic artificial sun with soap and a satellite dish

Simulating daylight with artificial lighting is not a trivial task. You’re faking a light that’s 93 million miles away. That means it’s an extremely tiny light source with light rays that flow almost parallel to each other, which has a huge effect on the shadows. But that’s not the only factor in daylight. There’s also that blue sky.

So, how can we set about reproducing it realistically? Well, Matt over at DIY Perks has a solution which, naturally, is a DIY one. And it does it by recycling an old satellite TV dish and combining it with a high powered LED (he recommends this one if you want to try it for yourself). It’s an absolutely fascinating approach that looks a lot more at the actual science of daylight than most photographers and filmmakers do.

The basic principle of Matt’s solution is quite simple. You suspend a light in a specific position in front of a parabolic reflector, and as the light hits the mirror and bounces off its surface, it reflects directly forward. No matter which part of the mirror light hits, all of it is reflected directly forward and the rays become parallel. This gives the impression that the light source is extremely far away – which, as you can see in the video, isn’t really the case!

Real parabolic reflectors are expensive, though. So, Matt gets around this by taking a standard satellite receiver dish – the kind you might have had sitting on the side of your house for the last couple of decades – and coating it with vinyl mirror film. Satellite receiver dishes are essentially parabolic reflectors for radio waves. And here Matt’s using it in the reverse function of its original design. They’re built to take signals coming down from satellites in the sky and no matter where they hit the dish, they reflect towards the actual receiver. The light is moving in the same path but in reverse.

The second part of the solution, reproducing the look of the light passing through the atmosphere and that blue sky we see above us every day… Well, the solution to that is a little less conventional but very impressive and extremely realistic.

[via ISO1200]