If I had a nickel for every marketing rep who told me the industry is moving away from strobes and towards LEDs, I’d be rich. LEDs are great. They are easier to work with if you’re indoors as they offer tons of control over the light. They’re also great if you’re shooting outdoors at night. But the truth is that not everything happens at that time. You can sit there and spend hours in Photoshop editing an image to fix the exposure and introduce lighting that wasn’t there, but then it looks fake. Most of all, you’re turning a three-hour photography session into an even longer process. Why do we have to work excessively for the shot?
How Exposure and a Strobe Work
Here’s a simple truth when it comes to flash photography and strobe photography. Working with a strobe gives you a million times more control! You may not know this because lots of folks just try to use a flash in TTL mode. For the record, TTL works by looking at the aperture and ISO of an exposure. Then it sets the flash output to what it thinks will work according to the meter. That’s why many photographers have complaints about how TTL works when they use it. The flash and strobe will do what it thinks you want. The better thing to do is to tell it what you want.
That’s why many photographers shoot in manual mode. So instead, let’s say you’ve got a strobe set to 1/4 power output. Here’s what happens:
- The shutter speed controls the ambient lighting in the scene and how much of it affects the exposure.
- The aperture controls how much of the flash affects the scene.
- The ISO controls the overall sensitivity to light.
And that’s it. That’s all you need to do. It’s incredibly simple. Here’s a rhyme I made up to help myself out:
If the flash output is too hot, stop the aperture down a lot.
If the flash emits little light, the f-stop must go bright.
How Exposure and an LED Work
I liken LED lights to a few other things. They can have a cinematic character and quality to them, or at least folks will say that. But I have doubts that anyone can tell the difference between one light output vs. another. But it’s all about practicality.
You know how a strobe and a flash work. But when an LED or constant light is in the scene, there is no overall exposure parameter control. Want to darken the ambient light? Well, you’ve got to use scrims or do it in post-production. Want to overpower the sun? Good luck. You’ll need to go into electronic shutter mode and potentially introduce tons of banding issues. And your LEDs will probably need to have the power of something like an ARRI light. For the same amount of money, you can do so much more with a strobe.
The other really big benefit a strobe has over an LED is flash duration. Flash duration acts almost like a second shutter speed. When a Profoto light says the flash duration is 1/18,000, it means that it has that level of stopping power. This translates into stopping some extremely fast motion. It also means it can kill ambient lighting in a similar way.