Lessons from the Shot: Why Learn Ratio Lighting? by Stanley Leary

 

by Stanley Leary

 
 
 
 Figure 1Figure 1a
 
First of all, there are times you need to be sure your photos can be reproduced properly. The most common type of photo used in publications is the headshot. There are some pretty cool lighting setups you can use. But if you’re not aware of how this will affect the photo in print then your client will be sorely disappointed with your photos.
 
Take this first photo where I am lighting the person with one light on a grid. This is a classic Rembrandt Lighting that gives you a nice triangle on at the cheek.
 
You can do this assignment yourself to understand how ratio lighting works. You need to first start with one light and then add other lights. Use this lighting diagram and the instructions below to duplicate this with your camera and off camera flash.
 
Description:
Rembrandt portrait using one grid light (above)
 
Items:

Monobloc with 10 or 20 degree grid - You may use any power setting you choose.  Be sure skin tone is properly exposed and correct white balance.

White backdrop - You may use a black background as well.  No other lights to be used in this assignment.

Woman - Please get the best possible expression.  You need to see a triangle on their cheek.  Be sure the triangle includes lighting their eye.

(D)SLR - Choose the lowest ISO setting for your camera.  Use a portrait lens 85mm - 100mm or if you don't have full frame then 50mm will be OK.

 
The first place that the above photo becomes a problem is with your newspaper. Especially when it runs in black and white. You see for the most part everything without light on it in the subject will be black in newspaper print.
 
So as to still get the nice shape that takes place with an off camera flash you need to add a fill light to help soften those harsh shadows so you can still see detail.
 
To get the second photo here you need to use the lighting diagram below and follow the instructions. Go ahead and shoot your subject with your camera and two lights.
 
 
Figure 2Figure 2a
 
Description:
1:3 lighting ratio.  This photo is classic lighting (figure 2 and 2A)
 
Items:

Woman - Your subject should have the main light lighting only part of the face and the shadows should be just a little to show the 1:3 ratio.

(D)SLR - Choose the lowest ISO.  Use a portrait lens 50mm if you don't have full frame camera can work.  No more than 100mm.

Octobox - This is your fill light and get just a reading of this 2nd.  Be sure it is 1/2 the power (1 f/stop less) than the main light. After this is done get a 3rd light reading of both lights which will be the setting for the camera. It can be level with the eyes, but you may have to move up with glasses to avoid glare.

Softbox - This light is your main light. Get a light reading with just this first. The light should be 45 degrees off the axis of the camera and 45 degrees above the subjects eyes.

White backdrop - the subject a few feet from the background and do not use more lights to light it.

 
How to figure the Ratio
 
You need to change your f/stops into ratios.  What I do is first understand that your main light is putting out twice the light as your fill.  You would think that this means you have a 2:1 ratio, but this isn't the case.
 
The reason is you must figure not by what each light is putting out, but how much light is hitting the subject. 
 
From the camera's perspective, everywhere the main light is hitting, so to is your fill light. You then need to add the main light and the fill for all those places which is adding 2 + 1 = 3. The shadow is only being lighted by the fill so no need for addition or subtraction.
 
On the subject the brightest areas being lighted by the main and fill get 3 times the light as compared to the shadows getting lighted by just the fill which we say is 1 amount of light.
 
This is what we call the 3:1 lighting ratio and very printable in a newspaper.
 
 
Adding a hair light (figure 3 and 3A)
 
Figure 3Figure 3a
 
Go ahead and then shoot this third shot and add a hair light. Use the diagram below and play with the exposure of the hair light till you get something you like.
 
Description:
1:3 lighting ratio.  This photo is classic lighting with hair light.
 
Items:

Woman - Your subject should have the main light lighting only part of the face and the shadows should be just a little to show the 1:3 ratio.

Monobloc with grid on boom

With dark hair start at same f/stop as main up to about 1 or 2 stops more.  With bald or light hair, be careful using hair light. Sometimes better to not use one.

(D)SLR - Choose the lowest ISO.  Use a portrait lens 50mm if you don't have full frame camera can work.  No more than 100mm.

Octobox - This is your fill light and get just a reading of this 2nd.  Be sure it is 1/2 the power (1 f/stop less) than the main light. After this is done get a 3rd light reading of both lights which will be the setting for the camera. It can be level with the eyes, but you may have to move up with glasses to avoid glare.

Softbox - This light is your main light. Get a light reading with just this first. The light should be 45 degrees off the axis of the camera and 45 degrees above the subjects eyes.

White backdrop - Keep the subject a few feet from the background and do not use more lights to light it.

 
Background Light
 
Figure 4Figure 4a
 
You can add color to your background by just putting a colored gel over a light and pointing it to the background. You need to be sure your other lights are not lighting the background. For these photos here below we used the first lighting setup with one light with a grid and then added the background light, (figure 4 and 4a)
 
Using a white background be sure your value on the background from the background light is -2 stops as compared to the main light. This will give you the same color as your gel.  If you want a darker color then even less light. If you prefer a lighter color add more light.
 
Once the lights are set up…try different ratios to see what looks good to your eye….and have fun.