Back in the day, when shooting film a Flashmeter and (expensive) Polaroid tests were indispensible in getting correct exposures but in a digital world filled with histograms and three-inch histograms the short answer is not always. While I usually use a flash meter or a hand-held light meter with a flash function when working with studio flash lighting I know several photographers that never use a meter under these kinds of conditions. And Ive been known on a particularly lazy day to do it myself. If you disagree with this approach, thats OK because a lot depends on the lighting setup used.
So let me rephrase the original question: Do you always need a flash meter? And if youd like to know what some of my friends do, heres the answer. They start by picking a shutter speed they know will synch the camera with the flash. If you don’t already know it you’ll find it in your SLRs Users Guide. Then they choose an aperture based on experience. Since most people photographers like to work with mid-range apertures in the f/5.6 to f/8 range they choose something in that range and then make a test exposure. At that point, looking at the screen and evaluating the histogram and next time they might take a bigger swing at selecting an aperture since the test shot was just a guess to evaluate the test exposure. Then they fine-tune it through additional test shots, including evaluating the histogram to zero in on whats considered the final exposure setting.
This is one way to get correct flash exposures but if you are using continuous lighting instead of electronic flash, bracketing using your in-camera meter is always a good idea. Tip: Bracketing is a time honored photo technique where multiple images of the same subject are made at different exposure levels. The idea is that one of them will be the best but even some may be acceptable.
Ashley Rae (above) was photographed using a monolight placed at camera left with a blue gel placed over the flash head. It was the only light source and no fill was used. The image was captured using a Canon EOS 50D and EF 85mm f/1.8 lens. Exposure was 1/125 at f/2.8 with an ISO of 400.
Joe is the author of the upcoming book, Studio Photography Anywhere (http://bit.ly/esapJx) coming soon from Amherst Media.