High Speed Sync vs ND
Do you guys know what the benefits and drawbacks of high speed sync versus ND's? When you raise your shutter speed up, you guys saw the flashes. Let me show you this again. Look at these flashes. Okay, what's happening is the sync speed on a flash means that under 1/200th of a second, your radio can communicate to the flash and it can fire in time. By the time the shutter speed, the shutter opens and it closes, it can fire off the flash. When you go above that, it can't match the speed, right? So what ends up happening is, if it actually lets you do it, this doesn't even let me do it. I can't bring the shutter speed above 1/200th of a second. But if it lets you do it, you get a black bar. You guys see the black bar that goes across the image where the flash fires in one section and doesn't fire in the other section? That's a sync speed issue. With happens is with full-feature flashes that offer high speed sync, when you use high speed sync, that flash didn't get- Nothing changed physic...
ally with the flash. It can't now fire within that 1/400th of a second or 1/800th of a second just because you pressed a button. What ends up happening is it pulses. So when I press this test button, you see that pulse? It does that exact same thing when you are firing high speed sync. Now if it's pulsing 50 times to fit in one of those shots into your shutter speed. Let's say at 1/1000th of a second, it has to pulse 50 times, like this. What happens to your flash power? It just dies, right? What if it has to pulse 100 times to get in a single frame at 1/4000th of a second? Or 1/8000th of a second when it has to pulse 500 times to get in a single shot? Your flash power dies dramatically. What we've found is that you're gonna lose at 1/8000th of a second, you're going to lose around eight to 10 stops of light from your flash. That takes you down to like a small percentage. 100, 50%, 25%, 12.5%, 7%, 4%, I used to be an accountant. I'm a photographer now this is why. Because I think I just halved something wrong. That's alright (chuckling). So, you get down to like 1% to 2% of the total output. Now if you use an ND filter, does your ND filter does this effect flash power? This is like a trick question. Does this actually, does this effect your flash power? (crowd chattering)
Yes. This stops down all light coming into the lens. But guess what> If I can get away stopping down four stops of all light to get my shutter speed down to 1/200th of a second, I still have my full flash power. So we're talking about an additional, this will get me four extra stops worth of light power from my flashes versus using high speed sync. Does that make sense? Nod or jump up and down, like, kick someone next to you. Do something like that so I know, yeah? There you go, I got an elbow, good. Little aggressive, but that's cool. So, that's the benefit of an ND filter over high speed sync and it carries true. The funny thing is that manufacturers are going to tell you, "Ooo, the new..." We love Profoto Gear, we use a lot of Profoto Gear. And everyone, Elinchrom, Profoto, everybody, will tell you that, "Oh, it has high speed sync now." For some reason, nobody publishes how much power you're losing with high speed sync. Nobody says it. I'm always like, "Have you guys published "how much power you loss, you lose?" And everybody's like, "No," and I always go test it and it's still the same thing. It's we're losing 7, 8, 9 stops of power, in that range. So, it's one of those things where if you have to, there's certain situations where you'd use high speed sync. That's if you're shooting sports, you need a fast shutter speed to freeze the ambient light. Like if you're shooting sports and you've got this motorcycle driving by your frame, and you need to keep it at 1/5000th of a second to freeze everything, you would use a high power, like a Profoto B1, or even higher power with high speed sync. You're cutting down a lot of the power, but then it's a high-powered strobe. So you still get more "umph" out of it. That's the one situation that you'd use it. Engagement photography, there's no dude on this planet that can run that fast. (audience laughing) Just not going to happen.