You are watching Digital Photography One on One, where we answer your questions. Here is your host, Mark Wallace.

I have been getting a lot of questions in my email lately and I really appreciate that. A lot of you have been asking me about lighting ratios and so, that is what we are going to focus on in this episode. So, what is a lighting ratio? Basically, a lighting ratio is the difference in brightness between the key light and the fill light. For example, if we want to have really nice, soft even lighting we would use a lighting ratio of 1:1. In other words, the brightness from the key light would be exactly the same as the brightness from the fill light. So, let us take a closer look at that.

In a 1:1 light ratio, the light from our key is the same as the light from our fill. If our key light metered at f/8 then our fill would also meter at f/8. A 2:1 ratio means that the key light is twice as bright as our fill light. This is a difference of one full stop. If our key light meter at f/8 then our fill light would need to meter at 5.6, a one-stop difference. A 4:1 light ration means that the key light is four times as bright as our fill light. This is a difference of two full stops. If our key light meter at f/8 then our fill light would need to meter at f/4, a two stop difference.

Okay well, that was cool. So, let us review. A 1:1 lighting ration has the same output between both lights. A 2:1 lighting ratio has a one stop difference between the lights. A 4:1 lighting ratio has a two stop difference between the lights. And an 8:1 lighting ratio has a three stop difference between the lights. So, what is the need of this matter? Well, lighting ratios help us to be consistent in our work as photographers. So, if we want to have flat light, we would use a 1:1 lighting ratio. If you want to do some really cool portrait work, we would use a 2:1 lighting ratio and if you wanted to have some really highly dramatic lighting, we would use an 8:1 lighting ratio, the higher the ratio the higher the contrast.

Now, I want to give you a demonstration of some of these lighting ratios, but before I do let me give you a reminder of some really important things. The position of your lights will make a dramatic impact on the contrast of your image. To get the maximum effect of your light ratios make sure your lights are at angle of 45º or more from your camera, the greater the angle, the greater the contrast.

For this episode, I have asked Megan to join us. Welcome Megan! And for the demonstration I have decided to keep things very simple. So, what I have is two monolights and each monolight, I have already setup to have it set to full power. And each one has a large soft box on it. Now, to make sure that things look great. I have set both of our lights up to about a 45º angle from the camera. So, now that everything is setup, the only things we need to do is meter and take the shot.

So, I want to come back here and what I want to do is have a 1:1 light ratio. So, the first thing I am going to do is meter the key light. Now, the key light is this one over here on your right side. So, I am going to set my luminousphere in a down position on my lightmeter, point it right at my key light and take the reading. Okay and that says f/10. So, now I am going to meter my fill light and see what it says. I am going to zip over here on this side, point it at my fill light and take that meter reading and it also says f/10 which means that both lights have the exact same output and that is a perfect 1:1 light ratio. And before I take the shot, I want to put my luminousphere in the up position, point it right at the camera and meter under Megan’s chin and this will give me a combined light reading. And that is telling me f/13. So, if you hold this for a second. Let us go and take a shot and see exactly what that looks like. So, I will set my camera to f/13. Look right this way. Perfect!

Okay, so now, we want to setup our lighting ratio to be a 2:1 lighting ratio which is a more standard portrait lighting setup. So, that means that our fill light on this side needs to be half the power as our key light. So, we have made some changes and our key light now meters at f/11 which means that our fill light needs to meter at f/8. That is a one stop difference between our key and our fill light. So, let me meter again the key light just to make sure. And that does meter at f/11 and now let me meter this. This is going to also meter at f/11 because we were at a 1:1 ratio and yet, but still at f/11. So, what I need to do is take the power down on this moonlight, so I will come out here and I will adjust that. I am going to tale my power down by half. It has got a little dial here. I will just put that right on half, hit the test button to clear the buffer there. Now, I am going to meter this again. I need to have it at f/8. And that meters right at f/8. We got sort of lucky. If it did meter to f/8 I could just fine tune that adjustment a little bit until it is just right. So, I have f/11 and f/8 which is a one stop difference. Then again I would put my luminousphere up, meter to the camera and take the shot that meters at f/10 actually.

So, what would happen if you did not know that the one stop difference is f/11 and f/8? If you do not happen to have that table memorized in your head which I do not, the Sekonic light meters have this really nice feature and I want to show you how to do that. So, to do this, what you can use is you can use this. It is the average or the Delta EV button. To meter this, what you would first do is take a meter reading of your key light. So, when I meter this, I have that set. Then I will do the—I will push the average button and that stores it in memory. Now, what I can do is come over here and meter the fill light and as long as I meter that and hold down the metering button, it shows me a delta, in other words a difference in EV. So, what the heck is EV? Well, it is pretty simple. A number of 1EV is a one stop difference. If you see a 2EV, that is a two top difference and so on. So, it is really easy to see if you have a one stop, two stop, three, stop or whatever difference between your key and fill light by using this difference mode on your Sekonic lightmeter. So, this is telling me that I have a -1EV reading. In other words, I have a one stop difference between my key and fill light. So, once I have that, I will hit the average button again to clear that out, point this right at my camera, meter and it tells me exactly when I need to set my camera too and I can take the shot. It is pretty cool.

So, let me show you all these light ratios now that we know how to meter. And we are going to stop you through 1:1, 2:1, 4:1, and an 8:1 light ratio setup just so you know exactly how they look. Are you ready? All right, let us get going.

Okay now, that you know about lighting ratios, you could put them into practice when you are making your own lighting setups. In fact, in the next episode that is exactly what we are going to do. I want to show you a few of my favorite lighting setups and also explain each of the lighting ratios that we used in each one.

Now, if you need more information about key and fill light or stops or maybe some nice charge to help you remember all of this stuff, make sure you check out the bonus materials at studiolighting.net. And as always if you have a question you would like me to answer just send it in to studiolighting@gmail.com. I will see you next time.

This episode is brought to you by snapfactory.com and studiolighting.net. For more information about our workshops, visit snapfactory.com.