The following post on the use of fill-flash in macro photography was written by professional photographer Ron Kruger. Learn more about Ron at the end of this post.
I’m an outdoor writer/photographer, and I’ve always admired those minuscule blossoms I see around my blinds and hides and along rivers and streams. This past spring, sort of as a sideline, or hobby with the hope of some potential profit, I embarked on a mission to record macro images of every tiny wildflower I could find.
As a professional, I’m always looking for ways to do things differently than the average photographer. One I’d like to share is fill-flash for macro, which we called flash-fill back in the day when you had to make all kinds of complicated readings and calculations to pull it off. I’m not talking about a dedicated macro ring flash, either, but your common, everyday external flash unit and/or your on-camera flash. Both work, and they work great together.
By together, I mean using the external unit as a slave, hand-held off to the side. This is best, but you can achieve very pleasing effects with the unit mounted to the hot-shoe, which is what I do most of the time. The secret is to use a diffuser and bounce plate to soften the light, yet direct it down on the subject at such close distances. Sometimes I’ll also put my cap (white or grey ball cap) or some other item behind the object to help contain the flash and provide a little backlighting. But the real key is to set your camera to AV (aperture priority) and use the highest setting you can (up around F-11).
As with all macro, it helps to have the camera mounted on a tripod, but not so much for long exposures. I most often shoot with a shutter speed that matches or exceeds the standard focal length and often lay on the ground to get shots of short blossoms and ground cover plants, hand-holding the camera. I use both a 100mm and a 35mm macro for this, but if your lens has a hood (such as my 100mm macro), you need to remove the hood, because it can partially block the flash output.
I can’t give you specifics on all this, because it varies with camera models, lens speeds and flash unit models (because of the flash unit’s power output), but the idea is to use as high an F-stop as possible and still retain enough light on the blossom itself. You’ll just have to experiment with your equipment.
What you are doing is pushing the edges of available light (flash) to isolate the blossom from the background. This works best on cloudy days, when you can get great detail and richness in the blossom (because of the high F-stop), but an almost black background.
I think the result are artistic. To see what I mean, visit my website at http://pa.photoshelter.com/user/ronkruger and click on the Tiny Wildflower Macros gallery. Images 2450, 0363, 7892 and 7898 are good example of this method.
Ron Kruger has been a professional outdoor writer/photographer for over 30 years, with thousands of images published, including quite a few covers. To view his online protfolio, go to http://pa.photoshelter.com/user/ronkruger