Camera Setup: Flash Synchronization
So the next thing that we have to choose on the camera body is what's called the synchronization mode. Okay, so we've talked about shutter speed, right. So when we take a picture, if, I'm gonna set the camera for a long exposure and I'm gonna put my microphone here real close to the camera so you guys can hear this. So as I take this shot (camera shutter clicks) Do that again. (camera shutter clicks) Clunk, clunk. Okay so what'd you say, is that a long shutter speed or a short shutter speed? Long shutter speed, okay cool in fact that was about a, what was that, about a half of a second or so. Clunk, clunk. And then here's a fast shutter speed. Right you all know this, I'm just making a point here. So here's the shutter speed of a sixtieth of a second. (camera shutter clicks) Clunk. (camera shutter clicks) Alright so what's happening there? Well, regardless if you have a long shutter speed or a fast shutter speed, the camera still has what's called a front curtain that opens up, and the...
n a rear curtain that closes behind it, and then they both reset to home. So every photo has a front curtain and a rear curtain and then they reset. Okay so let's go slow because that's easy to understand. So front curtain opens. And your flash can fire right then, pow. And then your shutter can stay open for a while, half a second. And then it closes and then they reset. So that's called front curtain sync or front curtain flash sync, right. The shutter opens, flash fires, it waits, and then it closes and bla, bla, bla. The other one is rear curtain sync. Okay, tough question. When do you think the flash fires for rear curtain sync? (laughing) At the rear, yes, good. (laughing) Give her a gold star. Alright, cool. So here we go. Just to make the point. Curtain opens. (loud mouth noise) And it waits. And stuff happens, people move. And then the flash fires and then immediately the curtains shuts. So you need to decide on most of these cameras when the flash fires. And if your shutter speeds are fast it really doesn't matter. It doesn't really matter to the photo. If your subject is stationary, like not moving, again it doesn't matter. Okay, it doesn't matter if the flash fires at the beginning or the end. But let's say that your subject is moving. Let's say you have a seven year old son and he's into skate boarding, okay. So now you're going to go outside and you're going to photograph your son. He's going to jump off a ramp. He's wearing a helmet and.. you can tell I'm a parent. Yeah. He's all safetied up but he's going to jump off a ramp, okay. So when you're taking that photo, let's say you're going to use flash. Do you want the motion blur of your son to be in front of his movement or do you want the motion blur to be behind the movement? Yeah you definitely want it to be behind the movement. Alright so let's think through how that works, actual mechanically. So he's going, he's moving and he's in the air. Your camera is stationary. Shutter opens and motion blur is happening. So let's just take the picture with no flash. Shutter opens and he moves across the screen and you got motion blur. Alright, so where does the flash need to fire to kind of get the frozen part of him, you know the pulse part of him? Does it need to fire at the beginning of the blur, (popping noise) or at the end of the blur? (popping noise) Like my, yeah it's very impressive sound effects. It needs to fire at the end of the blur, right. That's rear curtain sync. So, let me do that again. So shutter opens, he's in the air, he's moving. And then at the end of that the pulse of light happens and kind of freezes him in the frame. So most people haven't really thought through do I need front curtain sync. Do I need rear curtain sync. You can see in the studio it matters not. No impact. But when people are moving or things are moving you definitely want to use rear curtain sync. So how do we do that? On most Nikon cameras there's a flash button here on the side. And if your Nikon camera or your Canon camera doesn't have that flash button, you can go into the menu system into the flash settings and you'll find sync. It will say front curtain or rear curtain. So what I'm gonna do is I'm gonna push this button and then I'll show you here on the back of the screen how to change that. So, info screen. I'm pushing the flash button here. And then, let's see, my flash is sticky. Too many times in Africa. There we go. Alright, so down here it says flash mode. And then I can rotate my thumb here and hopefully the cameras can catch it. You can see I'm going through different flash modes. And then down here at the base, it's given me a little read out. So here you can see it says rear, rear curtain. So if I take a photo now with that setting the flash will fire at the end of the exposure. Okay notice there's nothing that says front. Well the default on all cameras almost is always front curtain sync. So your flash is going to fire at the beginning of the exposure, okay. So again, for most photography front curtain sync is just fine. But the last thing you want is for, you know, when the bride and groom are dancing, when they move this way, you don't want the motion blur to be in front of them. You want the motion blur to be behind them. So the way I remember this is blur to the rear, rear curtain sync, okay. (laughing) I got a clap on that one, that was cool. Blur to the rear, rear curtain sync. Those two things work together. Blur to the front, yeah, we don't do that. It just looks weird. You don't put blur in front of your movement.