Light Ratio Metering
To do this, what we need are two D1 heads and then two softboxes and then a Lex, so we'll have Lex come out in a second. What we're gonna do here is I wanna set up multiple lights and show how you can meter each of the lights individually to create a light ratio that can be repeated. It's something that's done pretty commonly in studio lighting. These settings-- light ratios just means how much brighter is one light to another light. In studio lighting, the light that's the main light that is the anchor point of everything you're doing is called either the main light or the key light and everything is metered from that reference point. You're saying the main light is at a power of whatever it is, and I want a a fill light, or secondary light to be half as bright as that. That's a two to one ratio. One stop difference, or maybe two stops less, or four stops, whatever it is. What you can do is as you're diagramming out your lighting setups, you can start writing out these ratios, and you...
can use these. Think of them as recipes for cooking a good dish. You can make a lighting diagram, and you know, hey, you know what, this is always gonna be 5:6, and this other light is always gonna be one stop less, and this other light is always gonna be one stop more. I'm gonna put it in this configuration with these modifiers. Then if somebody wants to come in and have a look that's the same, I can do it every single time because I have that formula, and your light meter is like a thermometer or whatever else you use to measure like a measuring cup I guess, just saying is this right? Is this the same as it was last time? It's very simple, so what we're gonna do here is we have a D1 there. We're gonna set up a second D1 here in a second, and then what we'll do is we're gonna have Lex come on out. If I can get this. Ah. These new speed rings are so not broken in yet. Rah. John, I'm gonna let you--
Deal with this so I can keep moving on. And is there one more softbox? We need one more softbox.
Oh, I got this one. I've got it. I've got it. (man mumbles) Yeah, the other soft one with the grid off. I just wanna stick you right here. Thank you.
All right. Bringing this guy over. Okay, so to do this so they can see, let's do it this way. Yeah. We'll have you spin around. Spin it around. That will be easier. All right, so I'm just gonna put a little softbox on here. Ah. Need to-- Brand new. There it goes. There we go. Okay, now we're ripping off the grid on the other one. That's set up there? Good. Good, good, good. Everybody needs a John Cornicello in their life. It will help greatly. All right.
I think the chatrooms would agree with that one, Mark.
Everybody needs a John Cornicello-.
What would we do without a Cornicello?
Everyone's been complimenting you in chat, John, saying you're a staple here at CreativeLive, and they love you.
He is. Everybody needs John to help them out. All right, John, if you can just get that.
And she's got the other softbox for you on that side.
Hey Mark, while you're setting up, another quick question.
If you were only to purchase one ND filter and not a variable, would it be the nine or the five?
(Blows raspberry) I love questions like that, 'cause those are impossible to answer. It's like, if you only had to-- So for me, I would get the nine-stop, 'cause that's what I'm using most of the time, but I don't know what they need that filter for, so it depends, it all depends. I don't know. I would go with nine, 'cause I'm using it for special purposes in the studio, but nine stops is like, crazy. That's so much, almost nobody uses a nine-stop neutral density filter, so I would get the five, yeah. I would say five, but I probably wouldn't even get that, because if you're a scenic photographer, what you need is a graduated neutral density filter that is dark at the top and transparent at the bottom, and it has a graduated-- and so it goes dark to light to light to nothing to block the sun and leave the horizon alone. And if I was trapped on a desert island, and I had to choose which neutral density filter to get, there are kits that you can get that have multiple neutral density filters in them. Full, two-stop, four-stop, nine-stop, graduated, 1/3, 2/3, yeah. And so you can get these kits that are spectacular, and that's what I would get.
Okay. So what we have here we have two lights set up, and what we wanna do is figure out how, and this is a lighting setup that's made specifically to figure out the relationships between these two lights, right? This is not a lighting set up that we'd traditionally use. So what I'm gonna do here, is I want to meter these lights independent of each other, and I'm gonna make them very directional, so it's even more obvious that we have a darker and a lighter side, so this is, again, just to illustrate this. So we're gonna put these out to the sides, and the way I'm gonna do this is specific to Sekonic light meters. John, do you have that light meter?
Okay. And then what we need to do is put a--
PocketWizard on both?
We just need one.
And go radio--
Just need it on one.
Gonna go with optical slave?
So what we're doing here, we need a PocketWizard to trigger these lights (beeps) That works. Do you know how to set that to--
Yeah. So the way that this is being triggered, by the way, is this has a PocketWizard in it. It's telling this light, and it's hitting this PocketWizard. This light is then firing, because this is telling it to fire. This flash has no PocketWizard on it, but we've set it up, there's a little infrared sensor here, and it looks for any flash that fires, and when it sees a flash fire, it fires. So what's happening is this is telling this to fire, it's firing, that sees that fire, and it fires. And I've gotten the question a lot, well doesn't that mean this is firing slower than this one, 'cause it'd be bloonk, bloonk? It's moving at the speed of light, which is faster than the radio is going, so no. It's going at the same time. You can't go faster than that. That's as fast as you can go. Right? Is that science? Speed of light, is that as fast as you can go? Good (sighs). All right, so what we're gonna do here, is I'm gonna illustrate this. Remember, this is not a lighting setup that we would actually use, but the steps are what we're talking about. So we are gonna first meter for the relationship, and this is going to be what we consider our main light, or our key light. Okay? That's what we're gonna say, even though these look exactly the same we have to start somewhere. So this is our main light, so I'm not gonna meter to figure out what exposure to use on my camera. I'm metering to figure out how bright this light is, okay? So what I can do, actually, let me back up. First, you would meter the key light, and get it set to the correct aperture value. So let's do that. Let's say we want the key light to be at F10. I would meter this, and that's at F9. Let's take it. F9. That's good. Close enough. So let's assume that we've measured this, positioned it, metered it, and now we're starting to add other lights. What I wanna do now is I don't wanna meter this for proper exposure, I wanna just see how bright it is. So I'm going to put the Lumisphere down and what I'm going to do is I'm going to point this from Lex's chin to this light. The reason I'm using her chin is I need a consistent point to measure all of the light from. So using her chin, I know that I'm metering from the same distance from this light and that light, and so I can get a consistent and accurate reading. So I'm gonna just swivel this, so I can see the reading. I'm gonna meter this, and I'm pointing it directly into that light, and a lot of times, I'll just stand in front of that other light, 'cause I wanna make sure that this one doesn't get there, so I'll meter that, and it's nine, 'cause I just metered it. What I'm gonna do next there is a memory button on this meter, and I am going to push memory. So F9 is now in memory. Then there's another little button up here, and it says average, and I guess I should do that Can you see that? Sorry. Average and that little triangle EV. That means delta exposure value, and we remember from math class that delta means the difference between. So this is saying, when I push this, I can either get the average, or I can get the difference between two different lights. I'm gonna push it, and there's this little A that shows up, saying if I click this and let go, the results that shows up is gonna be the average between two different lights, but, on this meter, if I push it and hold in, it's going to display the difference in exposure value. What is exposure value? It's gonna be measured in stops. So if it says one, that means one stop. If it says two, that means two stops brighter. If it says negative one, that means one stop less. Negative two, et cetera, and it might be 1.2 or 1.3, so I believe this measures in tenths of a stop. So what we want, we want this light to be one stop less than this light. That's what we want. And it could be anything. It's up to you to figure out your stuff, but generally, two-to-one light ratio, this should be one stop less than that. So what I'm gonna do now is go to the other side. Remember, I've metered that. I put it in memory. I pushed my little delta EV button. Now I'm gonna push and hold, (meter beeps and clicks) and this says 1.8, which means that this light here is 1.8 stops brighter than this one. That means we gotta take the power down on this by three stops. So on this one, I can go one, two, three. Three stops less. Now let me meter again. I know I'm gonna have to adjust a little bit for that .8. (meter beeps) So I do that. That's 1.2 stops less. So I need to go a little bit more, 'cause the .8. (meter beeps) There we go. Oops. Wrong way. (meter beeps) I think that's as low as this will go, so we have to do something here. So I'll do this. Measure it. Yeah. So it can only go down. This is at the lowest setting it can possibly go to, and it's only 1.2 stops less. So what I can do, is I can move this back. Right? We're gonna get less light when we move back. But what's happening when I move this back? What's the penalty for that?
Harder light. (audience murmurs).
Yes. It's harder light. And so I'm changing the quality of the light, which means sometimes, this guy, you might need to get a little bit larger softbox, so that they're the same size. And so, that's one of those things that you have to take into consideration. So I'll meter it again, (meter beeps) and it's 2.1. So we'll take a tenth of a stop difference. So now, this light is twice as bright as this light, or this light is two stops less than this. Two stops? Did we go to two stops? We only went to one stop right? Yeah. So let's just go with it. This is two stops less than this one, even though we originally said we were gonna go to one stop we went to two. So that's four times less powerful. That's the square, right? Yeah. All right. Now-- I know, I need my coffee. Now we're gonna meter this, and we're gonna meter it for exposure. What I need to do is I need to clear the memory out on this. All I need to do on this meter is go to a different mode and come back and that clears the memory. On other meters, there's a memory clear button. They didn't make that on this one. You just change modes and come back, and it works. So now we're gonna measure for exposure, and the reason I'm measuring back here is if I meter right here, I'm blocking my light. So I can either come back here and measure like this, or sometimes you're gonna have lights behind, and that won't work, so sometimes, you just have to worship, and do this, right? And that'll work just fine. So let me go ahead and meter this. There we go. 7.1 is what we got. So all of that light together is 7.1. Let's take a picture and see what it looks like. Let's see what it looks like. I like that shot of you, by the way. I'm like, hell, that's pretty cool. (audience laughs) All right, 7.1. So I'm putting my camera to 7.1. We're going to take the neutral density filter off. Can you hold that? Thank you. And we're gonna shoot this shot. Shoot the shot. And what you'll see, is we have light fall-off on one side of Lex's face, and we have a nice pleasing portrait, and if we wanted to repeat that look a million times, we would know, two two-by-three softboxes, make this one two stops less, and off to the races we go, okay? So that's how that works. For my taste, this might need to go down even more, that one up a little bit more, but you know, there's the portrait. Works pretty cool. And again, this is not a setup I would normally use with those lights totally to the side like that. All right. So do we have closing questions? I think we're out of time, is that right?
I actually had a question about the shape of the softbox. Usually, what would you use, a square, a rectangle, or do you go to OctoDome?
These two-by-three softboxes and the four-by-six softboxes are the softboxes I use every day, and that's why we have them here, because I wanted to use the same stuff. So that's what I use. (audience whispers)
What's the advantage to the OctoDome versus these, or the other way around?
The OctoDome is great for shooting-- A, the specular highlights are round, which I sorta like, but also, it's very large. It's very, very large, and so it works terrific for full-length shots. I've done a lot of shots that are environmental, where I have like somebody in a chair at a little place, and I use that to get in there, and it just seems to work a little bit nicer than a big square softbox to get in a little bit tighter, 'cause, since it's a different shape, I'm able to cover more of the area than just a square. I'm covering more area. Does that make sense? Yeah. Covering more area by doing that, and I think it looks a little bit nicer. But the thing is, if there's a photo club in your city where people share photo gear and do shootouts and stuff like that, you should do it because, A, you get to meet a lot of cool people, but also you get to see the differences between different types of umbrellas and softboxes and Octo boxes and stuff, 'cause people will bring stuff, and I can describe it to you, but until you see it, it doesn't really-- you don't have handles on it really, and so I can say, "Yeah, the Octo box is better for filling little places on location, and the big, four-by-six softbox is better for beauty shots, and things like that. But until you see those pictures and actually experience it for yourself, it's not gonna sink in and be in your brain.