How to photograph close-up with flash
Electronic flash may be the best way to stop the action, obtain consistent exposures, and creatively illuminate a small aperture field of view.
Many roads lead to Rome and there are different ways to skin a cat. So it is with close-up and macro photography. So much so that any how-to-do-it article can only scratch the surface of this problematic genre of nature photography.
If finding and framing small living creatures is a biological problem, photographing them is an optical problem complicated by high magnification, shallow depth of field, and small working distance. Because close-up and macro photography require maximizing depth of focus, thus a smaller aperture, effective lighting may be the biggest problem.
If the problem is to photograph small creatures alive and in the field, magnification and stop action capacity will be needed. This suggests a need for flash - but does it give a lovely light? It does indeed, especially mixed with natural light. In fact, increasingly subtle use of flash seems to be a trend in outdoor photography. Using flash, the quality of light can be manipulated by varying its intensity, direction, color, and diffuseness. Most important, we can use it to maintain small apertures for greater depth of field. This article takes a brief look at using electronic flash as a tool to solve certain of the aesthetic and technical problems inherent to camera work close-up in nature. How to use a hand held "flash-on-camera" set up as well as manipulating the quality of light in total flash and fill flash situations is described.
As a specialist in insect photography, I need flexibility and versatility in my equipment. A lot can happen in the time it takes to change a lens, wind the film, or calculate an exposure. I use flash in most of my photographs of insects and spiders and mostly work with living specimens in their natural environment. When photographing nature wild and free it is important to have equipment that is simple and easy to use. It is much easier to respond to the sudden appearance of an exciting subject in the field if the camera and its flash are light enough to easily hold by hand. Simply stated, the advantage of flash is lots of light of short duration in a compact package.
The electronic camera system and modern flash technology are light years ahead of manual systems. Combined with an in camera TTL metering system, flash use has become more versatile and easy to use. The older methods may still be useful but a macro lens that can focus to 1:1, a built in winder, and especially TTL (through-the-lens) flash capability have both simplified and enhanced the creative possibilities in close-up camera work.
The first question to arise is how large a flash is needed. That depends on optics and aesthetics. Working in the macro range at more than life size magnification, as well as using flash as the only source of light, often requires a powerful flash. On the other hand, close-up work (magnification less that 1:1) and fill flash photography require surprisingly little light. For example, I find that a small flash unit with a guide number of about 20 (ISO 100 in meters) gives ample light when used with a shorter focal length lens such as 60 or 105 mm. Using a longer lens of 200 mm or more requires more light because of the longer working distance. Larger flashes may have useful options such as rear curtain sync and adjustable light output, but the most important feature to my mind is recycle time: high power output and especially TTL capability are convenient, as we shall see, but the critical features enabling rapid response in the field are small size, light weight, and a quick recycle time.
The easiest flash to use is the ring or macro flash attached directly to the lens front filter ring. Especially the kind with batteries and electronic circuits connected externally adds little weight to a hand held camera. The ring light, however, is disdained by most close-up workers because its light appears unnatural. The ring light, with a circular flash tube, produces shadowless illumination, whereas the macro light, with two, three, or four small flash tubes can produce a complex shadow pattern. I find a ring light awkward to use as its bulk can block my view of the subject and may prevent the camera from moving up close without snagging on surrounding foliage. Because these units produce relatively little light, they are not effective with a long working distance (telephoto) lens. Most ring lights are not useful in very close focus situations because they emit their light from a stationary position in front of the lens. Nevertheless, a ring light can be useful as a fill or even as a main light when used along with other sources of light as described under aesthetic considerations in close-up imaging.
Although a ring light gets the flash off of the cameras hot shoe and up front where it is more effective, an improvement would allow precise control of the position of the flash with respect to the object photographed. A bracket to hold and aim the flash and a dedicated connecting cord are needed. Besides acting as a third arm (but perhaps not replacing your assistant) a flash bracket should aim the flash where you want it. It must be flexible enough to allow quick adjustment of its angle and direction if the subject changes its position within the frame. Rotating the camera vertical to horizontal, or changing the magnification and the working distance, may also cause a need to reposition the flash. There are flash brackets on the market but they allow little flexibility so I prefer to make my own of simple materials as illustrated in the photos of the flash-on-camera set ups I most commonly use in field photography.
If the ring lights advantage is easy use, the flash brackets improvement is precise control of the light. It should be noted that a flash bracket can be constructed so that it can accommodate more than one flash as well as flash units of various design. Insect photographers seem to prefer to use a bracket that mounts a small flash aimed at the subject from above and to the side of the lens (an angle of 30 degrees is often recommended). Although it is possible to produce more natural appearing light using two flashes, one giving a little more light than the other and so producing a softer shadow, the additional complexity may be limiting in the field.
Basic flash technique for close-up and macro work is as simple as controlling the flash to subject distance for manual exposures or using TTL flash technology.
The easiest way to control flash exposure is to use TTL metering. Camera bodies since the 80s are usually equipped with TTL capability, and dedicated flash units are available in great variety. The dedicated flash unit has a built-in sensor tied directly to the camera exposure controls. Connecting the flash through the cameras hot shoe enables communication of information between the two units while exposure-control indicator lights are visible in the camera viewfinder. With the camera set to manual override, select a shutter speed and aperture (probably your fastest flash-sync speed and a small aperture for greater depth of field) and simply take the picture. The camera shuts off the flash when its meter senses enough light for the level selected on your exposure compensation dial.
The trick to using TTL metering for total flash exposure is to estimate a proper compensation setting. How much compensation to give depends on the metering system and the tonalities within the scene. I usually use multisegment metering but average or center-weighted metering works just as well. Since light meters by design render every scene as medium tone, using the meters reading may not produce a literal rendition of the scene. For example, if a small object on a large light ground such as a bee in a buttercup is to appear in the photograph as the eye perceives it, an exposure compensation of perhaps +1.3 is needed. In this case, plus compensation or additional exposure is needed because the meter tells the flash to render the light color of the flower a medium tone. In contrast, an object in a dark surround such as a large black caterpillar on a dark green leaf will need minus compensation (perhaps -0.3) because the meter will again tell the flash to render the scene a neutral gray or medium tone, in this case, overexposing it. The secret to using TTL lies in learning to estimate the average tonality of the subjects you photograph. Practice makes perfect.
Determining flash exposures manually is a bit more complex than using TTL technology. You will need to determine proper exposure experimentally over the magnification range that you intend to use for each lens and flash combination. Fortunately there is a helpful "rule of thumb": if a small manual flash unit is placed at the lens front, a proper exposure for an ISO 50 film will be approximately f16. The "small flash f16" suggestion is at least a starting place for testing a normal focal length lens on extension within a magnification range of about three quarters to almost twice life size. Once you know the flash to subject distance for any given f-stop and extension, using a flash bracket makes it easy to position the flash for a proper exposure. However, as in TTL metering, it will be necessary to compensate for tonality of the subject. A light colored object will need less exposure than a dark one. To compensate, simply increase or decrease the aperture by half a stop or move the flash perhaps a centimeter closer to or farther from the subject. Compensation by changing the flash to subject distance is repeatable if one part of the lens, say the forward margin of its filter ring, is used as a point of reference for the placement of the flash.
You may be surprised to learn that I use both manual and TTL flash set ups. First of all, the manual system is a back-up in case of failure of the more sophisticated electronic systems. Once I know my flash to subject distance for a given f-stop, I basically just point and shoot. Furthermore, the manual camera and dual flash set-up shown in the illustration is lighter in weight and smaller in bulk than the electronic configurations. I carry the manual set-up in a separate camera bag ready to shoot at a moments notice. The manual set-up is "dedicated", so to speak, to taking total flash photographs. I use the electronic camera and computer flash system when I need to use multiple flash units or want to mix the ambient light with flash for more creative lighting. This is when it gets complex - but then read on: nothing ventured, nothing gained.
The aesthetic qualities of flash photography
Outdoor photographers have a particular preference for soft diffuse lighting - early morning, late afternoon, and especially cloudy-bright ambient light sends the nature photographer heading for the countryside. Although using diffuse ambient lighting may be the best way to photograph a sleeping insect or a dew covered spiders web on a windless morning, when the sun comes out and living things begin their busy lives, photographing close-up becomes a much greater technical challenge.
The simplest approach to close-up photography is to use natural light. Natural light is beautiful light but it is not adequate for most of the subjects that I photograph because I need to maximize depth of field and freeze camera and subject movements. Using flash, I generally get sharper pictures than I do with ambient light exposures.
An alternative to natural light is to use flash as a substitute for the sun. Total flash illumination can be as simple as using a single flash or as complex as transporting an entire studio out into the field. It seems important to keep in mind that it is possible to create different light for different subjects. For example, a single flash can be positioned at a large angle to the camera (almost parallel to the subject) casting strong side light to bring out subtle textural details. Using a dual flash set up, the intensity of the shadows can be manipulated to mimic soft diffuse natural light. Or a ring flash can be used for shadowless illumination along with other techniques such as selective focus or background contrast to create an allusion of depth and space in the image. While a complicated set up limits the photographers mobility, combining several flash units increases the possibilities for modeling the light such as using a ring flash for fill light along with an off camera slave as a main light.
I find that total flash is adequate illumination when the subject is on a surface with background objects in the scene close enough to reflect light from the flash. However, if your background is deep space, you will end up with photographs that look like they were taken at night by flashlight - the background will be black because flash illumination falls off with the square of its distance to the subject. In other words, to retain tonality in the background when using on-camera total flash, the subject must have a backdrop close behind it or an off camera flash must be used to illuminate the background. Alternatively, a painted backdrop can be placed close behind the subject but a more practical alternative may be to seek another angle from which to take the picture, or find another subject, or create a whole new light.
While total flash may be the insect photographers most useful tool, the real magic of flash is using it in concert with the sun to control the contrast within the image. As well, by carefully balancing ambient light and flash it is often possible to circumvent the black background problem of many close-up photographs. In fact, the subtle use of flash to add fill light to the shadows or to illuminate a subject back lit by a stronger light is often used by outdoor photographers to create a "magic sense of light".
With fill flash, the main light is the sun and the flash is one or two stops weaker than the ambient light. Studio photographers will note that this is the same effect that a correctly positioned reflector gives to a main light source. The goal of fill flash is to open up the shadows or to add a little sparkle to your subject but using reflectors out in nature is just too cumbersome for me. To keep things simple, I recommend using a dedicated flash and TTL metering to determine your fill flash exposure. As a starting point from which to bracket, I set my aperture and shutter speed via a multisegment meter reading, then dial in minus one exposure compensation on the camera. If I have a chance at a second shot, I stop down in one half stop increments. To add just a bit of crispness to a natural light photograph, I use TTL exposure compensation minus two.
I must admit that fill flash is my favorite kind of light. It is especially apropos a subject where the background is nicely lit. If nature is handing me a beautifully lit and patterned background, I try to preserve a feeling of the natural lighting in my photographic interpretation of the scene by using flash to supplement the ambient light. Using a bright sky as a backdrop is one example where flash can be used to illuminate the subject while natural light provides the background. In this case, I might use sunlight combined with fill to illuminate the subject and a flash sync shutter speed that would record the sky a desired tone of blue.
There are many ways to approach a subject and many kinds of light in which to photograph. Extending the wonder of nature photography by using flash opens a myriad of new creative options in close-up photography. For example, total flash extends the recording possibilities to the limits of camera optics. By combining the light of the sun with the light of flash, magical qualities can be added to the close-up image. But most of all enabling a ride to creativity is the patience to experiment with the variety of technical and aesthetic options available to the photographer.
Click here to see camera/flash setup.