I was recently asked to demonstrate the difference between strobe on camera and strobe off camera. The examples below show how changing the position of the strobe, on and off camera, changes the lighting effect. I also factored in the available light which also affects both exposure and color.
I started my exposure by reading the background and underexposing it by 1 stop. The strobe was placed off to the side and fired using a pair of PocketWizard TT5s on the strobe and on the camera with an AC3 controller on the camera. The AC3 gives me the ability to dial up and down my exposure of my strobe from my camera. The exposure on the background was controlled by the camera setting and the light on the model was controlled by my strobe output. The photographs were created using a Nikon camera and a Speedlight.
For my first test shot, my strobe which is daylight balanced, was much warmer in color, then my background. (Picture 1) Thank you to my assistant Kalin Luong for modeling!
To balance out the colors of my strobe and background, I put a Rosco half CTB filter over the strobe (CTB is Color Temperature Blue). Now that the color from the strobe and the color background were similar, I did a custom white balance off of my strobe light. (Picture 2)
For comparison, here is the same location, the same time and the same photograph with on camera flash!
A larger light source gave us softer light. One of my favorite portable light modifiers is the Chimera beauty dish! As the daylight decreased, the predominant light source became the tungsten light on the building. We no longer needed a CTB because the blue available light went away. The CTB gel was removed from the strobe. I set my camera's white balance to daylight.
The strobe produced the correct color on the model's face, while the buildings in the background had a warm color from the tungsten lights on the front of the buildings.
I hope you can join me at one of my up coming "Location Lighting Workshops™" in Telluride, CO
and at SWPP in London, UK.
All Rosco products are included in Rick Friedman Rosco Location Lighting Kit!