Blue Water Drop. 580EX II with blue gel, positioned behind a sheet of white paper, to light the water surface. 430EX II with red gel located camera right to illuminate the drop. ST-E2 as wireless E-TTL trigger. Shot in a glass of water in my studio. f/6.3, ISO 100, 100mm macro.
The previous chapters in this book deal with figuring out the fundamentals of flash photography. This final section is a compendium of ideas of other directions to explore.
Slow shutter sync and its usefulness for exposing a background correctly with low light levels were discussed early on in this book. Also mentioned was the importance of using a tripod to reduce motion blur in areas not illuminated by flash.
The same principle can be deliberately exploited to take advantage of motion blur for dynamic effect. Essentially, a photo taken with flash and a slow shutter speed can provide an interesting mix of frozen flash-illuminated subject and ambient-light-illuminated motion blur. The effect isn’t always easy to predict, but it can be very striking and exciting when it works.
Introductory material for beginners make it sound as if hard light is malevolence in photon form, and that professional studios have nothing but huge softboxes in them. This isn’t the case, of course. Light that’s too soft can be boring and flat. Shadows define a picture as much as light, and skillful photography is as much a matter of choosing and positioning good light sources as it is composing the elements of the scene.
Standard automatic flash lighting systems emphasize getting as much light on the scene as possible. But brightly lit scenes can be a bit boring. Spots or patches of light in shadow can make for much more interesting pictures. Think of the dark chiaroscuro or tenebrist paintings of 17th century artists such as Caravaggio: shadowed scenes with pools of light gathered around, or hinting at, mysterious narratives.
The zooming mechanism in most portable flash units is a great tool for narrowing down the cone of light from the flash head. Some photographers think of the zoom as a “portable snoot” rather than a mechanism to compensate for focal length. Naturally, the zooming mechanism has to be under user control, but fortunately most Speedlites have manual zoom override.
Add-on flags (light-blocking panels), snoots, and grids are also useful tools for keeping the light focused in one place.
One of the first rules most beginners are taught is never to point a camera toward the light source. This is a useful rule for learning how to meter, but backlit scenes can be quite interesting.
Silhouettes are a particularly dramatic way to light something. Even showing the flash in frame can bring in a sense of drama. Positioning a light to the side of the subject, but behind it, can give an attractive halo of light, helping separate the subject from the background. This technique lends itself to manual metering, however. Automatic metering tends to underexpose badly if the flash unit is visible, since it’s designed to record reflected light and not direct light.
As discussed in section 6.3, each flash exposure is essentially a double exposure—there’s the subject lit by flash, and the background, which may be lit by ambient light. In the case of night or other low-light conditions, it’s fairly easy to reduce shutter times to minimize the amount of light contributed by ambient without affecting flash. But in daylight, this becomes trickier, because the X-sync limit puts an upper ceiling on the maximum attainable shutter speed.
Fortunately, high-speed sync means that X-sync is easily broken. You can set a high shutter speed to keep ambient exposures low while exposing the foreground normally using flash. This technique can create moody atmospheres under what appear to be fairly uninteresting or banal lighting conditions.
A basic lighting tool for cinema and stage is the “cookie,” short for “cucoloris.” The best part about “cucoloris” is that nobody seems to know where the word comes from. Whatever its etymological origin, a cookie is simply a flat board with holes cut into it. Or a piece of mesh with fabric leaves stuck on to it. Or a bunch of branches. Or a glass of water. Or anything, really, used to break up light into interesting shadows.
Speedlite-type flash units are ideal for working with cookies because the hard-edged light from a battery unit automatically wants to cast sharp shadows.
A fun way of taking interesting photos in the dark is to use open flash, described in sections 5.5 and 11.2. It’s certainly the most direct way to apply light to a scene.
The basic technique is to lock the camera to a solid tripod, find a location with little or no ambient light, and then open the camera’s shutter in “bulb” mode. This is best done with a remote that can be locked in the open position. Then it’s just a simple matter of walking around the scene, firing the flash by hand to illuminate areas of interest. Colored gels can be taped over the flash head to illuminate the photo with different colors of light.
The Neverwas Haul shown in figure 15.19, a self-propelled three-story art vehicle in the form of a Victorian house, was created by the Travelling Academy of Unnatural Science. In this shot, the Haul was lit primarily by the full moon, camera left. The lengthy exposure, nearly a minute and a half, made the picture look like it might have been taken in late evening light. The keen-eyed observer will notice that there are two shadows cast by the vehicle, hinting that there was also a large light tower camera right, positioned a good mile away.
The vehicle is outlined by handheld flash triggered manually. A 580EX II was fired at full power at various positions around the vehicle and through its port-side windows to backlight its steering wheel. The flash was colored using red and blue filters for effect. More subtly, there was also a single half-power burst fired onto the left side of the vehicle, with a 1/4 CTO filter, to fill in the shadowed areas by the wheels and the staircase. EOS 5D mark II. 70 seconds at f/7.1, ISO 100. 35mm.
Canon Speedlites with manual controls or old flash units with manual metering are ideal for this application, since the output power can easily be adjusted. It helps to wear dark clothing and point the flash away from one’s body. Naturally, a flash unit isn’t the only tool for doing this sort of photography. People often take outdoor night scenes using high-powered floodlamps, or indoor photos with small flashlights (electric torches) or blinky light toys.
“Stroboscopic” photography is the process of firing a sequence of brief flashes during the course of a single photographic exposure. The result can capture the steps of a dancer in motion or the swing of a golfer, like the classic photographs that Harold Edgerton took in the 1940s and ’50s. Each frozen moment is recorded on the same frame, like a multiple exposure.
The ingredients required to take a stroboscopic photo are a Speedlite (or other flash unit) with stroboscopic capabilities, a very dark background, and a relatively light-colored moving subject. Reflective or light backgrounds don’t usually work because the multiple pops of light will build up cumulatively to overwhelm the foreground subject. Put the camera on a tripod, install fresh batteries in the flash unit, use either M (metered manual) or Bulb modes, and ideally use a remote shutter release. Multiple Speedlites can be controlled wirelessly for more light output if necessary. Stroboscopic mode is not compatible with second curtain sync or high-speed sync. 15.22 and 15.23
The 400EZ series and all 500 series Speedlite flash units have built-in stroboscopic flash capabilities, known in the Speedlite menu as “MULTI.” All models can specify the number of flash pulses per second (i.e., the frequency in Hertz), as well as the length of time the flash unit will fire. Some can also specify the total number of shots to be taken per exposure, but older models require this to be calculated by hand. The full details for engaging stroboscopic flash are described in section 9.21.
Note that there are some practical limits posed by stroboscopic lighting. First, a flash unit can only fire a certain number of times before it overheats, so it can’t be pressed into service as a disco strobe light at your next party. It also can’t fire full-power pulses very rapidly, since the unit needs time to recharge its capacitors. For this reason, Speedlites are pre-programmed with flash frequency and power limits.
While flash units are used today mainly as a photographic light sources, the flash tube was originally used as a device for stopping time—at least, photographically speaking. In the mid-1920s, MIT’s Harold Edgerton was studying the behavior of synchronous electric motors. He had made some calculations predicting their performance and built a mercury arc lamp that could photograph the spinning motors as they were put under load, thereby testing his theories. Over the next few years, he generalized the concept for photographic applications, eventually switching to xenon gas in the tubes. Edgerton was following in the footsteps of photographic pioneer William Henry Fox Talbot, who in June 1851 used an electric spark to freeze the motion of a sheet of paper fastened to a rotating disc.
Today, the same photographic flash units that are used for snapping photos can be used for freezing motion. The duration of a flash pulse can be set in milliseconds, making it much faster than a mechanical shutter. Since the light pulses are so brief, exceeding the highest shutter speeds of most cameras, the field is often called high-speed photography. There are a few basic points to keep in mind.
First, the faster the object motion that needs to be stopped, the briefer the flash of light needed to freeze it. Ordinary subjects, such as people and slow-moving cars, can easily be frozen by the pulse of light from a regular flash unit. For this reason, portraits and similar shots always look sharper when taken with flash. However, really fast-moving objects such as water drops, hummingbirds, and bullets need extremely brief light pulses.
Second, AC powered studio gear is usually not the best option for freezing motion. Most studio units control the brightness of light output by changing the amount of power discharged through the tube. They often have long “tails” as light output drops off. In contrast, battery-powered flash units control overall light output by altering the duration of the flash pulse. A full power pulse from a Speedlite-type unit is actually not all that brief—values of 1/700 sec to 1/1000 sec are typical. But at low power settings, the light produced by battery units is extremely brief, since power to the tube is cut off very rapidly. Therefore, high-speed photography is best performed with ordinary battery flash units at low power settings, or studio units designed specifically for motion-freezing purposes. If the light from one unit is insufficient, then multiple units can be set up to fire simultaneously. Note also that many flash units will extend the duration if power is low, and the fastest flash bursts will be from fully charged units.
Manual timing is pretty tedious work, so a flash trigger timer is highly recommended for high-speed photography. These electronic devices can fire a flash after a beam of light is broken (a falling water drop, say) or after a microphone hears a sound (perhaps a balloon popping). Variable time delays can then be set so that the flash fires at the perfect moment to capture the action.
Many people build their own high-speed triggers, so this has become a popular photographic hobby. However, people low on electronic skills or time can also purchase advanced computerized flash triggers such as the ones shown opposite. 15.29
The left-hand device is the deceptively simple looking Universal Photo Timer from UniversalTimer.com. While compact and equipped with a simple LED display, it has five basic functions.
It can perform time lapse photography and other timed work as an infrared remote; it can trigger cameras and flash units in response to external events such as water drops and the like; it can work as an optical slave for a flash unit; it can perform stroboscopic flash; and it can operate as a remote shutter release. It has two sockets for controlling two separate flash units.
The right-hand device, the StopShot timer from Cognisys, has an advanced LCD screen with control over three separate output devices plus timing and intervalometer options. It supports conditional triggers for crossed beams (e.g., a flying insect will only trigger a shot if two beams are broken, not just one) and can memorize preset configurations. The maker also sells a variety of input devices, such as laser sensors.
A common photographic problem is taking a photo of something made of reflective material, such as an oil painting or anything under a sheet of glass. Art documentation has to deal with this problem on a regular basis. The usual suggestion is to put a polarizing filter on the lens. This helps, but any reflected light sources still appear in the photo. A solution? Cross-polarizing.
Cross-polarizing involves putting a sheet of polarizing plastic over a light source, such as a flash unit, as well as placing a polarizing filter over the lens. The lens filter is then rotated so that it’s aligned at 90° to the material on the light. When a photo is taken, non-polarized light will record as usual, but polarized light such as direct reflections will almost completely vanish.
This work by street artist SNUB23 demonstrates the technique. Since the art was made using glossy enamel spray paint, it was very difficult to photograph without getting rogue hotspots and reflections. Additionally, the art was located in a narrow stairwell, which limited lighting choices considerably. The photo to the left has a very objectionable hotspot. The photo to the right was taken from the same position with the same lighting, but with a polarizer placed over the lens and a sheet of polarizing plastic over the flash head. The polarizer was rotated until the hotspot vanished.
This technique is also useful for nature, wildlife, and food photographers who photograph wet or moist surfaces such as the eye of a fish or a sliced piece of fruit. It can also reveal interesting structures in minerals or reflective surfaces.
Incidentally, cross-polarizing can also reveal stress lines within transparent plastic objects made using injection molding. The normally transparent items suddenly burst forth into a rainbow of stress patterns. (Though to be honest, the easiest and cheapest way to photograph these patterns is to put a clear object in front of a polarized light source, such as ordinary LCD monitor, and put a polarizer on the lens.) 15.34
There is much to be learned by studying the works of great painters. They only had oils and canvas rather than CMOS image sensors and xenon flash tubes, but they sure knew a thing or two about light. One painter whose techniques are of great value to portrait photographers is Rembrandt van Rijn.
Many of Rembrandt’s paintings are lit predominantly from one side. This effect can be reproduced photographically by positioning a key light to one side of the subject, fairly high up. The other side is filled in by either a lower powered light or a reflector. The result is a simple and elegant portrait, with the shadows providing a dimensionality to the face. A key hallmark of the Rembrandt technique is that the side of the face in shadow typically has a downwards-pointing triangle of light on the cheek, under the eye.
While the formula doesn’t have to be strictly followed to work, it can be a useful starting point for basic portrait photography, as shown here.
Bamboo. Sagano bamboo forest. Kyoto, Japan. Sometimes flash can be used to very subtle effect. This photo uses predominantly ambient lighting, but a 580EX II was fired at full power to lighten the color of the nearest bamboo trees, providing a little more depth to the scene. 0.6 sec at f/11, ISO 100, 17 mm.
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