Stepping up to Double Lighting
For all you flashonthecamera photographers out there, you've come a long way but there's a higher lighting plateau of quality photography called double lighting. Are the benefits of using two lights for your social events worth all the trouble and extra cost? Sure, the flash on the camera is safe, foolproof, and convenient, but if you compare the two types of lighting, the difference is striking.
First, the color is more intense. The main light strikes the subject at an angle, sending the reflected, colorless light off axis, away from the lens. Except for highlights, the absorbed and scattered light entering the lens contains only saturated color. The light on the camera serves two purposes: to keep the density level of the shadow areas high enough for good contrast and detail, secondly to evenly light the whole picture area, and thirdly to flatter the faces and remove the bags under the eyes. In order to achieve the above benefits, a proper ratio must be retained. One easy way is to set the lens on F8, the fill flash on F8 automatic, and the modeling light on F11 automatic. This configuration should produce twice as powerful a light coming from the modeling light as from the fill light no matter what the distance from the lens to the subject.
Of course, a flash meter should be used to verify and fine tune the output. A second method sets the fill flash on manual one half power and the modeling light at manual full power. This setting requires the F stop to be changed if the distance from the lens to the subject changes significantly unless OTF (offthefilm) is available in the camera. While the fill flash can be conveniently kept small, there are several options available for the modeling light. A small silver umbrella reflector (minimum 18 inches in diameter) is the least expensive and does a good job. Better is a soft box (minimum 12 inches in diameter) but requires a more powerful head.
Simplest is bare bulb which is soft but not too flattering to faces and requires a lot of power. Four hundred ASA film is fast enough to use with 100 WS electronic flash. I recommend the use of a radio slave to trigger the second light for a guaranteed proprietary use. Other flashes in the room will have no effect on your second light, saving the batteries and preventing other photographers from using your light.
While a light stand is sufficient to support your second light, with a little instruction, a live person will save you a lot of running around. The modeling light should always be situated to the photographer's right or left side, producing a thirty degree angle to the subject. If the subject is twenty feet away from the lens, the modeling light should be seven feet to your right or left. An added benefit is that the backgrounds will be softly lit, but will never over power the subject in importance. Unfortunately, with the beautiful results you are sure to get, you will have to double the price of your services.