|Photo by: Maile Powell|
The second assignment for the students in my photo class this week is 3:1 Lighting Ratio.
|Nikon D4, Nikon 85mm ƒ/1.8G, ISO 100, ƒ/5, 1/200|
3:1 lighting ratio. This photo is classic lighting.
Octobox closest to subject
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.
Your subject should have the main light lighting only part of the face and the shadows should be just a little to show the 3:1 ratio.
Choose the lowest ISO. Ideally on full-frame camera a lens close to 85mm and on cropped sensor a 50mm. Set your shutter speed to the sync speed for your camera [in your camera manual] or slower. My camera was 1/250 but I shot at a slower speed of 1/200.
Octobox behind the camera
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.
First set the main light and here is what that will look like:
Due to using such a large soft box the shadows are not as severe as in our first assignment using the grid light. Some of the light is bouncing off a white wall a few feet to the left of the model or right of the camera position.
Turning the main light off after finding out your setting you need to take a reading and get the fill light to 1 stop less than the main light. The main light was ƒ/4 so the fill light should read ƒ/2.8.
This is what it looks like without the main light on. You can see a little darker but no real shaping of the face as the main light which is 45º to the side.
When you combine them you get the first photo of the model we started with.
The main light is twice as bright as the fill light. So to show this using math we would say the main light has value of 2 and the fill light has the value of 1.
Where both the main and fill light fall on the face is getting the combined value of the 2 + 1 = 3. However in the shadows only the fill light is hitting those and therefore the value is only 1.
So the bright areas get 3 and the shadows 1 giving you a 3:1 lighting ratio.
Now I showed the students how they can add a background light. I put a blue gel over it to show them they can also color the background.