Be sure to review Part 1 from last week to establish a foundation and obtain more information on how to use the tool.
Technology is wonderful. I take for granted that I’m able to converse with someone halfway around the world and simultaneously see their face on video. I can talk into a speaker and adjust the time of day my sprinkler system shuts off. I can travel at 600 mph on a jet for 14 hours and send a text to someone thousands of miles away. And, most of all, in complete darkness, if I place a battery-powered flash atop my camera, I can make a photo of what I can’t even see.
Given a flash’s wonderful attributes, can it have drawbacks? Yes. When used alone on the hot-shoe, the light is direct and not very flattering. Front light doesn’t allow texture or form to be recorded. If the subject is close to a background, dense black shadows appear behind it that look awkward and unnatural. Red-eye is common although a pre-flash helps minimize it. A benefit to nature photographers who use flash as fill is that these factors don’t negatively affect the image.
Flash As A Main Light
If a situation allows, I use a multiple flash setup. One unit is used as the main light. It’s held to the side and above the camera to imitate light from the sun. Another flash is used on the right side of the camera. Its purpose is to fill in the shadow areas cast by the main light to soften the contrast. The fill flash should be one to two ƒ-stops less powerful. A tissue or diffuser can be placed over the flash head of each unit to soften the light. These items lessen the amount of light that strikes the subject, so be sure you purchase powerful units—those with a high guide number.
If the sun creates a lot of contrast, turn the flash into the main light and let the ambient light act as the fill. Get close to the subject so the illumination from the flash is brighter than the sun. Shadows disappear and result in even light and provides a balanced ratio of flash to daylight.
Backlight can be very dramatic. But if it’s the only light source, at the expense of obtaining a properly exposed subject, everything else in the image suffers from overexposure. Flash works great in this situation. It brings the ambient light and the light emitted from the flash closer together. A technique I often use is to underexpose the ambient light and have the flash become the main light. This gives the illusion of bringing the subject forward in the picture as it stands out from the background.
Capturing Motion
A key advantage flash has over other light sources is its ability to arrest motion. Flash goes off at very high speeds. Because the duration is extremely short, which could vary from 1/500th of a second to 1/50,000, subjects that move can be frozen in mid-flight or stride. The closer the flash is to the subject, the faster the light shuts down. If the subject is close, a quick burst is all that’s necessary to expose it. What this translates to is the ability to freeze a fast-moving object because the flash fires at very short durations.
A hummingbird’s wings can beat at a rate of two hundred times per second. Taken without flash, the wings are often recorded with a blur. To freeze their motion, I use flash. I set up two flashes with one that lights the bird from one side and the other as a source of fill to light the opposite side. It creates a naturally lit scene. The main light is placed close to a flower from which the hummingbird feeds. The other light is placed the same distance but at half the power. I use an aperture of ƒ/16 to keep the entire bird in focus. Because the main light close to the bird, even at ƒ/16 I get a fast enough burst from the flash that allows me to arrest the motion of the wings.
If you try to photograph flowers on a windy day, it’s frustrating. Flowers are small subjects, so small apertures are required to have the complete flower in focus. This dictates slow shutter speeds. Slow shutter speeds coupled with wind make for poor images unless an intentional blur is the goal. I use a multiple flash setup or a single flash off-camera in conjunction with a reflector to kick light back onto the shadow side to solve the problem. Again, because the duration of the flash determines the exposure, if the flash fires at 1/5000 or faster, it freezes the flower.
Check out Part 3 next week where I’ll cover other uses for flash.
To learn more about this subject, join me on a photo safari to Tanzania. Visit www.russburdenphotography.com to get more information.