4.5 Background Light
In this lesson you will learn how to add a background light to the shot. You will also learn how to meter for the background and use that metering to match the background intensity with different color filters on the background light.
1.Introduction2 lessons, 04:19
2.Light Metering2 lessons, 13:46
3.The Light Source3 lessons, 22:29
4.The Shoot6 lessons, 51:17
5.Conclusion1 lesson, 01:27
4.5 Background Light
In this lesson I wanna continue working on the shot by adding a background light to my thunder gray background. Now the light that I'm gonna use for the background is another one of my Alien Bee B800 studio strobes here. Now, I could use a speed light for that. It's perfectly fine. I don't need a tremendous amount of power. But this gives a really nice, soft quality to it. And, I do like to use studio strobes whenever possible when I'm in the studio, because that way I don't have to worry about the batteries running down. In fact, I could use speed lights for all of these but I like to use these when possible because it's a little bit more convenient. So I have this set up here on this short little stand. And this is just a really inexpensive, I think it's a 20 inch lightweight light stand. I do have a little bit of a weight on here. This is not a sandbag, this is actually a six pound ankle weight, but I like the way that it velcro's around. Because these legs are pretty low, sandbags don't like to sit on here very well. And I don't need a whole lot of weight to hold this down. So this little ankle weight actually works really, really well for this particular stand. So I want to set this up behind and underneath the table here. So it's not in the shot. And I'm gonna adjust the position to create a nice little vignette on the background here. Can turn the modeling lead on so that you can see what this is doing here. And if I get this closer, it's going to create a smaller little hot spot of light. The only thing that I really need to make sure is that it's not in the shot of my camera. If I push this farther away, the light field in the background of the beam field of light is going to get a lot bigger. So let me see what this looks like, cuz I do want a little bit of been vignetting in this. So let me see if that is visible from my other camera. I know you can see in the video camera, but my other camera is lower. I can see that just a little bit so I'm gonna pull that back just a hair. So right now this strobe here is set to a quarter power. I don't think that's really going to affect the exposure too much. Let me just pop this guy up here. It still says F10, which is pretty close to what I have my camera set to. Let me take a test shot and see what this looks like. Just jump out of the way here. It looks okay, but it is pretty bright. So I'm gonna turn this down a good amount, maybe to one-sixteenth power. And give it another shot. That's more in the neighborhood. So that looks okay. Now the blue in the background can be added in post production fairly easily. But the more we can get right in camera I think the better off we're gonna be. So all I have to do is grab a blue gel and throw it over this background light, and we should be good to go. But I'm going to have to adjust the output of the light to compensate for the light loss in that blue gel. And I don't really know how much to do that because I haven't metered the background. So what I'm gonna do is use my light meter here, right about here. And take a measurement of the background, it says 7.1. Now that is just a reference number. When I throw the blue gel on here. What I can then do is re-meter the background and adjust the output so that I'm getting about the same brightness that I was without the gel. So I'm gonna start with this really super saturated gel here. I'm not actually sure what number this is. But I wanna give it a shot, and if it's not I'll try something else out. Just gonna use a small piece of tape here. And you can see what that did to the level of background just with a modeling light. It's definitely going to reduce the output a whole lot. Some of the more saturated gels can cut the light output down to something like 4%. So if I take another meter reading on the background here, remember I was at 7.1. Now I'm at 3.6. So I'm gonna need to boost up the power here, re-meter at 4.5. Kick that up even more. 6.3, getting there. Little bit more. 7.1. So remember before I was at one-sixteenth power? Now I'm a half power on this light. So huge, huge light loss there with this gel. But let me see if this is the right color. I'm gonna take a shot here with those settings. Wow, that is very, very saturated. But you can see if I go back and forth between that and the previous shot, the relative brightness on the background is the same. Now it looks punchier on the blue because that blue is hyper-saturated. I'm not really sure that that's the right color. So I'm going to swap that out with another gel. So I think I'm going to try slightly less saturated gel here. This is actually CTB. I think it's full CTB, which is color temperature blue. And this is what you would use to change a tungsten or incandescent lighting source to daylight. So it definitely looks blue, but it's not so super saturated like that other blue that I was just using. So I'm gonna turn the modeling light off, cuz I don't really need it. I don't really wanna trap a whole bunch of heat in there. So I'm gonna re-meter the background here. So when I changed that gel, I didn't change any other settings on the light and now it says F13. So I'm gonna kick this way down and re-meter. Now I'm at F9. Take another meter reading. There we go, 7.1. And, in fact, if I look at this guy here, I'm just slightly over 1/16th power which was Really close to where I was before. So this is going to be blue, but it's not gonna cut out a whole lot of light. So, let me jump out of the way here and take another test shot. [SOUND] There we go. There! That's a nice subtle blue. You can see that's much less saturated than that other blue. It's a little bit more subtle. And I think that's the color that I'm after here. So now that things are looking really good. What I wanna do is maybe adjust the power ratio of my main key light to my fill light. And see if I can maybe reduce the highlights just a little bit and increase the fill just a little bit more. So to do that, I'm gonna again use my light meter. And I'm going to turn this down to one-quarter power. So I was at a half, and then a re-meter right here. Actually I just took a picture of that so. So this says F8. So let me just increase this, my fill light just a little bit and then take another meter reading right here. That's F11, so I might have got a hold of that little bit too much. So let me just re-meter this and make sure that we're in the neighborhood here. That says F9 right there. So let me take a shot With these settings here. I should have a little bit more of a balance of this fill light here. And essentially the effect that I was going for is that the highlighting here would be knocked down just a little bit. We'd still see it but it wouldn't be super super bright. And I'd get a little bit more of this luxurious giant fill lighting here that I have. And I think I like that. In fact, I might be able to go down a little bit more on this light here, just to give maybe a few options. I'll go down to one-eighth power and then I'll re-meter. It still says F9, and I think what's happening here is that this light right here is at F9. So to prove that what I can do is just light off and then take another meter reading right here. And of course, that's not gonna work because this guy right here is an optical slave. So in order to fix that, what I'm going to do is I'm going to grab another radio trigger here. And I'm going to attach a PC sync cable here. I'll just use a little bungee here to attach this to the light stand. Turn this guy on, and now this is no longer on optical slave, it's on the radio trigger. So now I should be able to meter right here. And Indeed I am getting F9. So now I really don't have to worry too much about what's going on between this right and this light as far as the combined exposures. Because most of the exposure is coming from this one light right here. So I can take a quick test shot here. And you can see what I did here is I turned my highlight control light over here down to 132nd power. And that's going to create a much more subtle highlighting along the side of the shoe there, one that I really don't like that much. That definitely has a huge effect from where we were before. So I want to pop this guy back up to a quarter power, cuz I think that's where I was before. Take another shot. And I think that is where I want to be right there. That is looking fantastic. If anything, I think maybe the background light is a hair too bright. So I'm gonna turn this down just a hair. I'm not really worried about what the meter is going to tell me because I'm just using my eye now. My eye is telling me that it's a little bit too bright. So let me try this. That, to me, looks a little bit better on the background there. But I do have those options where I kick it up a notch and where I lowered it down so that it's a little bit more subtle. And I have a bunch of different variations of what's going on there with the shoes as well. Now, I did bump the shoes a few times. So if that's not really perfect then I won't be able to use those the comp anything together. But I do have some options that look essentially exactly the same. So now that we've got the shop pretty much nailed. What we could do is go one step further for our client and give them a little value added. So in the next lesson. We're gonna move the lights around and do some really quick metering just to set up maybe one or two more looks with these shoes. So check that out coming up next.