Want to take your portraits to the next level with lighting ratios?
You’ve come to the right place.
Because in this article, I’m going to share everything you need to know about lighting ratios for amazing portraits, including:
(And much more!)
So if you want to become a portrait photography master, then let’s get started.
As a math term, a ratio is a comparison of one thing to another.
So when calculating lighting ratios, you measure the light falling on the light or highlight side of the face and compare it to the light falling on the shadow side of the face.
For instance, if you have twice as much light falling on the highlight side of your portrait, then the lighting ratio would be 2:1. If you have four times as much light falling on the highlight side of your portrait, then the lighting ratio would be 4:1.
But how exactly do you measure light?
While you can do it with the built-in meter in your camera, it is much easier and more accurate to use a handheld incident light meter. You see, your in-camera meter takes a measurement of the light reflecting off your subject – whereas a handheld meter can measure the amount of light falling on your subject and therefore gives you a more accurate value.
To properly measure and understand lighting ratios, you need to know a few things.
First, light is measured by f-stops. The aperture dial on your camera generally goes up in 1/3-stop increments, though the full stops for aperture are f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, etc.
(A simple way to remember all the numbers is to memorize f/1 and f/1.4; all the other pairs are doubled from these with a few rounded off.)
You also need to understand that shutter speeds are also representative of f-stops, with the full stops at 1s, ½s, ¼s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, etc. Shutter speed full stops are easier to remember as they are generally doubled (with a couple instances of rounding, such as 1/8s to 1/15s).
Finally, know that each full stop is double (or half, depending on whether you go down or up) the amount of light compared to the previous one.
For example, if you are shooting at f/4 and want to shoot at f/5.6, you will need to double the amount of light to get an equivalent exposure (you’ll need one more full stop of light). If you want to narrow your aperture by 2 stops, you’ll need to add 2×2 – or 4 – times more light. Likewise, 3 stops correspond to 8 times more light (2x2x2) and so on.
Knowing this, you can figure out how to create and measure ratios. In the next series of photos, I will demonstrate four different lighting ratios and how they were achieved.
A 1:1 ratio is even lighting.
In other words, there is no difference in the meter readings on both sides of the face. As you can see in the photo above, 1:1 lighting is very flat, and it can be achieved in a couple of different ways.
First, you can use fill flash and make the flash equal to the main light source. This is harder to achieve until you’ve had some practice, and you’ll often end up overpowering the light with flash.
Secondly, you could use a reflector. It will need to be very close to the subject, and the goal is to eliminate all shadows on the subject’s face.
This is a 1:1 ratio, and it’s pretty easy to see and recognize visually.
As the numbers suggest, a 2:1 ratio occurs when one side has twice as much light compared to the other.
So knowing that plus what you know about f-stops, we can set up this lighting ratio.
First, put your subject into the light where you are going to photograph them.
Using a light meter, measure the light falling on the side of their face closest to the light source (i.e., the highlight side). Let’s say that measures f/8. (Keep your shutter speed the same for all measurements to maintain consistency.)
Then bring in your reflector and use the light meter again, but this time measure the light falling on the side of the subject’s face that is farther away from the light source (from here on in, this will be referred to as the shadow side).
Note: If you are using a handheld meter, make sure to shield it from excess light that comes from the other side of your subject. So if you are metering the shadow side nearer the reflector, shield the meter so the main light source isn’t hitting it.
Now, you know that your highlight side has a reading of f/8. To achieve a 2:1 lighting ratio, you’ll need to get your meter to read f/5.6 (which is one stop less light) on the shadow side. So adjust the reflector distance until the meter settles on f/5.6.
Also, it may help to study the image above and recognize the contrast range from the highlight to the shadow side of the face. It’s subtle, but you should be able to see it.
A 4:1 ratio is double a 2:1 ratio. So if 2:1 featured twice as much light – or one stop – how much light will a 4:1 ratio require?
The answer is four times as much light (2×2), which is a 2-stop difference from the highlight side to the shadow side of the face.
I teach an available light class, and I always recommend working with natural light before you advance on to speedlights. With available or natural light and a reflector, it is much easier to learn and practice lighting because you can see what happens as you make changes (WYSIWYG). Flash is harder to predict as you can’t see it without actually taking a photograph.
So if our main light (the window) is still at f/8, what should be the value of our fill light/reflector (or the shadow side) to achieve a 4:1 ratio? Let’s do the steps again: f/8>f/5.6>f/4.
Therefore, two stops less than f/8 is f/4 (and this is the desired measurement to create a 4:1 ratio). Look at the photo above and compare it to the 2:1 image; do you see how the shadow side is getting darker?
The last ratio we’ll look at is 8:1.
The 8:1 ratio requires 8 times as much light, or 3 stops, on the highlight side of the face compared to the shadow side.
As you can see in the image above, 8:1 lighting is quite dramatic, and anything greater than 8:1 will not hold much detail on the shadow side of the face at all.
In fact, prints have a maximum contrast range of 4-6 stops, so unless you want one side of the face overexposed or the shadows pure black, I suggest keeping your lighting ratios at 8:1 or smaller.
Note that an 8:1 ratio can be a bit tough to create. You may need harsher lighting and possibly a black reflector to add blacks into the shadow side (rather than reflecting light onto it).
We calculate it the same way as above: if 4:1 is 4 times the light, then 8:1 will be 8 times the light, or 3 stops.
So if we are still at f/8 on our highlight side, we need to get our shadow side to read: f/8>f/5.6>f/4>f/2.8.
Now that we have this knowledge of ratios, let’s put it to use! Remember: The ratio can add to the success of your portrait, or it can ruin it.
If you look at the example images again, pay attention to how the mood of the image changes with the ratio. Notice how the higher ratios create more drama and power. Notice how the lower ratios are softer and more innocent.
Generally somewhere between 2:1 and 4:1 is the commonly used ratio for most portraiture. It’s enough to create three-dimensionality on the face, but not too much to create unattractive, deep shadows. I personally like a 3:1 ratio (1.5 stops) or a 4:1 ratio, myself.
For a child or baby, you often want a lower ratio because the softer result goes well with the subject matter. But a grizzled old cowboy with weathered, wrinkled skin and unkempt whiskers looks much better with 4:1 or 8:1 lighting. Why? He’s rougher, tougher, and can handle the increased contrast, plus it’s suitable for his look.
If you’re worried about not owning a handheld meter, you don’t necessarily need to go out and buy one. I’d only suggest you do that if you plan on getting into studio lighting. Otherwise, just practice seeing the difference between the various ratios (which is why I suggest natural light), and if they aren’t a perfect 4:1 or 8:1 or whatever, then it doesn’t matter. Just learn to recognize when it’s too strong and when it’s too weak for the effect you want to create.
Here’s another example of ratios at work. None of it is right or wrong, but which do you think is the most appropriate ratio for my subject? Figure that part out, and you’ll be ahead of the game!
Note: I’d like to thank my subject, Gabriel Biderman from B&H Photo Video, for these shots.
Now that you understand the lighting ratio basics, let’s take a look at some quick tips that’ll make your photos look better.
First, get your subject out of the sun. Shooting in bright sunlight makes it almost impossible to control your ratios, plus the light won’t be desirable or flattering on the subject’s face. Use natural light from a window with indirect lighting (no direct sun coming in) if you can. And if the sun is streaming in, try adding sheer curtains or even stretching a white bed sheet across to diffuse the light.
Second, here are some lighting ratio starting points:
Finally, keep in mind that there are no steadfast rules on how to do ratios in portraiture. Like everything in photography, it’s about learning the techniques, then using them as suggestions while you experiment and find your own style or voice.
For instance, can you put 8:1 lighting on a glamorous movie star or 1:1 lighting on a coal miner? Absolutely!
(I’ll even give you some homework that’ll prove both ratios can be effective if they are done well.)
Your homework assignment is to research the following photographers. Tell me how they broke the general rules I’ve mentioned above, yet still had great success and amazing images:
Those three photographers right there are some of the greatest portrait artists to ever live. Learn from them.
Now that you’ve finished this article, you know all about lighting ratios – and you know how to use them for stunning results.
So what’s the next step?
Practice! If you simply dedicate a few minutes per day to working with portrait lighting, you’ll become a master in no time at all.