THE SOLUTION

The idea is to severely underexpose the ambient light in the background, creating a deep black pocket, while using an electronic flash as your sole light source to illuminate the flower. Remember, every ambient exposure is a combination of aperture and shutter speed, while a flash exposure is dependent only on the right aperture. A fast shutter speed will underexpose the ambient light only, while the flash illuminates the flower. This technique is best done under cloudy skies, in open shade, or when light levels are lower, such as early morning or late afternoon. Use an aperture between f/8 and f/22, which will offer a good supply of shutter speed choices that will underexpose the ambient light without being too fast to sync with the flash. (The shutter speed must not exceed your flash’s fastest sync speed, usually 1/200 sec. or 1/250 sec. Check your flash’s manual to find out what it is.)

Start by choosing an aperture—let’s say f/8. Then meter off the flower to determine what your shutter speed would be for a correct exposure. Now, underexpose by 3 stops. For example, let’s say I choose an aperture of f/8. I meter off the flower and my camera indicates a correct exposure at 1/30 sec. If I increase my shutter speed to 1/250 sec., I have just set a 3- stop underexposure.

Then, fire up your flash. Enter the same aperture on the back of your flash (in this case, f/8) and it will indicate the correct flash-to-subject distance. If you keep your flash that distance from the subject, you will record a perfect flash exposure of the subject surrounded by a sea of darkness. That darkness is nothing more than the ambient light that is out of the range of the flash recorded as a 3-stop underexposure.