Flash Photography for Macro and Close-up
By Rod Deutschmann, Robin Deutschmann
Published by Amherst MediaRobin and Rod Deutschmann explain how to light and expose the foreground and background of your images when you're shooting close-up in this excerpt from their Amherst Media book Flash Techniques for Macro and Close-up Photography.
This excerpt from Flash Techniques for Macro and Close-up Photography is provided courtesy of Amherst Media. To purchase the book and learn more about the publisher, visit the Amherst Media Web site.
Flash photography is a two-step process, whether or not it’s for close-up/macro photography. You have to light both your foreground and background, balancing (if you so choose) ambient and man-made light. Sometimes you can light both with your flash/flashes (especially when shooting close-up and macro images) and sometimes you can’t.
It’s a two-stage process when adding light with an off-camera flash. An unmodified flash was held directly above the plant in this image, but it was employed because we made our background dark first. This image, surprisingly, was shot in the middle of the day under direct sunlight. We didn’t like the way it looked, so we changed it. We chose an aperture and shutter combination that would produce a dark background and keep the flower in focus. Then we simply added light to brighten our flower. Remember, you are not always trying to capture something the way it looks—with an off-camera flash, you can create something completely different.
Camera Settings. When you have to use natural light in your image (to illuminate a background, for instance) we suggest dialing that in with your shutter speed or ISO setting right after you choose an aperture size. Some photographers change their aperture to adjust their lighting; we don’t do this. Instead, we choose the aperture setting based on the desired depth of field. We want a specific amount of focal distance to appear in our image and we work very hard to make sure it’s perfect. Giving up that control makes no sense whatsoever.
Keep in mind, though, that as you begin choosing smaller and smaller apertures for greater depth of field, the apparent power output from your flash will dwindle. Smaller apertures strip light from ambient sources and cut the amount of usable light coming from your flash. When shooting with smaller apertures, be prepared to use more powerful flash settings.
You’ll also have to come to grips with certain modification issues. We’ll cover the modification choices you have later, but for now it’s important to remember that as your light source increases in size (such as when using a softbox), the apparent power output of your flash diminishes. This can be solved quite easily by moving the flash closer to your subject, decreasing the size of the modification tool, increasing the actual power output of the flash, or choosing a larger aperture (again, not recommended).
Flash Sync Speed. When using an off-camera flash, whether for closeup work or not, you have to work within or around your camera’s flash sync speed. Surpassing this will prove detrimental to your image. The flash sync speed is the fastest possible shutter speed your camera can shoot at and still acquire all the light emitted from your flash. (Check your camera’s manual if you are unsure of what this shutter speed is.) If you shoot with a shutter speed faster than this, then a portion of light emitted by the flash will be hidden by the camera’s internal shutter blade—provided, of course, that you are using a standard digital camera; there are several camera models today that employ an electronic shutter where this will not be an issue.
This image was shot at the camera’s flash sync speed of 1/200 second.
Shutter speed of 1/300 second.
Shutter speed of 1/400 second.
Shutter speed of 1/500 second.
Each camera has a flash sync speed—a speed at which full flash coverage is attained. If you choose a shutter speed faster than this, a portion of your scene will not be lit by the flash, as illustrated in this series of images. The more you exceed the sync speed, the larger this blacked-out area will become.
Even though it was the middle of the day, the bold colors, rich mood, and crisp focus in this image would not have been possible if it weren’t for the addition of flash. Remember that a scene does not have to be lit the way it appears. By simply visualizing an alternative and adding a flash (employed off-camera as shown in the image below), you can make the magic happen with any camera, at any time, in any location.
High-Speed Flash Sync. To circumvent the flash sync speed, you can purchase a special flash that allows for full flash coverage well beyond your camera’s flash sync speed. This high speed sync option will require very specific camera and flash combinations and is usually quite expensive—plus it’s a power hog. Using this system means that your flash is actually firing many times, very quickly, during one exposure. This does fill in any gaps created by the traveling shutter blades, but it cuts the available flash power substantially. This can be a huge problem if you’re already using a large light modifier or smaller apertures.
Camera Filters to Cut the Light. Thankfully, there are other ways of cutting light that don’t cut the apparent power from the flash—ways that won’t break the bank, as the high-speed sync option might.
One option is to use neutral-density filters instead to cut the excess amount of light. Another option is simply to cross two linear polarizers. This is an ages-old technique that is growing in popularity again as more and more photographers experiment with off-camera flash. Simply stack two linear polarizers in front of your lens, rotate the bottom one to eliminate glare and turn the top one to eliminate ambient light. It works like a charm—creating what is, essentially, a variable neutral-density filter. (Note: From our experience, the polarizers do have to be linear for this to work—and not all brands play the same. Stacking two circular polarizers produces nothing but shifting colors throughout your image.)
As you can see from these images, a simple adjustment to the in-camera contrast setting created two very different images of the same subject. In the left-hand photo (where the setting was set low), a softer impression is made. In the righthand photo, we see the strength and aggressive “flavor” that a higher contrast setting offers. If you begin incorporating how you feel into the development stage of your message-building process, your pictures can only get better.Category: How-ToClick for more articles of: Rod Deutschmann, Robin DeutschmannRelated Articles:Balancing Flash with Ambient LightExposing for Sunrises and SunsetsThe Characteristics of Light