SOURCES OF LIGHT
Learn how artificial light can widen the range of possibilities in nature.
For some nature photographers, especially if they wish to show nature as it is, the use of artificial light can be a big no-no, but the truth is that many situations are difficult or even impossible to capture without artificial light.
Mirrors
Mirrors help to accentuate silhouettes, change the angle of light, and even fortify the intensity of ambient light, which helps reduce unwanted shadows. In a studio a fill flash would do the trick, but it is less useful in field conditions because it tends to scare off animals. Using mirrors can be challenging even in familiar settings because of the earth’s rotation, which causes the direction of light to constantly change.
I first used a mirror while photographing fungi, and from there I got the idea to cast light on birds at a bird bath. I hung a mirror to a tree opposite my photography blind, tied cords to the mirror’s lower corners, and trailed them into the blind. Then I was able to adjust the mirror, quietly from inside the blind, without scaring off the birds. You might notice light coming from two directions in these photos, yet the backlit details add value to the images and, in my opinion, offset any loss of realism.
I also employed mirror reflections successfully when photographing a European Bee-eater as it was digging a nest hole. The birds begin rather late in the morning, when sunlight hits the ground at an angle that is already so big that the quality of light is harsh and causes too much contrast. I pitched my tent blind facing the rising sun so that the European Bee-eater was in a direct line between me and the sun. With the mirror propped against the blind, it reflected light on the bird from a very low angle. This softened the backlight and brought out the bird’s beautiful colors.
European Bee-eater digging a nest hole (Merops apiaster)
Nikon D300, 300mm f/2.8, 1/2500 second, f/4.0, ISO 320, manual focus, Gitzo tripod and video head. Hungary, May 2008.
European Starlings bathing at a drinking station (Sturnus vulgaris)
Nikon D200, 300mm f/2.8, 1/60 second, f/2.8, ISO 400, manual focus, Gitzo tripod and video head. Hungary, May 2006.
A lamp behind the birds illuminates them in flight during a long exposure. European Greenfinches and House Sparrows (Chloris chloris and Passer domesticus).
Nikon F8008S, 300mm f/2.8, 1/2 second, f/4.0, Fuji Velvia ISO 50, manual focus, Gitzo tripod and video head. Hungary, February 2003.
Lamps
Lamps are extremely difficult to use in bird photography because lighting can be problematic to set up in the wild where electricity is usually not available. But in places where you can attract birds to a bird bath and where you have access to electricity, such as a garden, it’s worth experimenting with a couple of 1000-watt lamps to create conditions identical to sunlight. I have used this technique in Norway in the winter when daylight lasted only an hour or so. Squirrels and jays visiting a bird feeder were oblivious to the 1000-watt light just a yard away from them. The lamplight mixed into the scarce ambient daylight gave the image an evening effect.
A Eurasian Jay lit by a lamp (Garrulus glandarius)
Nikon D200, 300mm f/2.8, 1/1600 second, f/2.8, ISO 1000, manual focus, Gitzo tripod and video head, 1000-watt lamp. Norway, November 2006.
Flash Photography
Flash is the most widely used source of artificial light in bird photography—but who knows, maybe in a few years action photography will resemble still photographs taken from motion pictures, which would cause stage lighting to be more common than flash.
Many photographers shy away from using flash because natural light is difficult to achieve with an artificial light source, and also because the intensity of flash light is not suited to shooting a series of frames of a quickly moving animal that is often more than 4 m (13 ft) away. Nevertheless, in the past couple of years roughly half of my pictures have been taken with flash.
Before you switch your flash on, it is worthwhile to learn some basic rules about flash photography.
Combinations of ambient light and flash yield more natural-looking results. Great Egret (Ardea alba).
Nikon D300, Tokina 10–17mm fish-eye lens (10–17mm f/3.5–4.5), 1/4 second, f/4.5, ISO 100, manual focus, 8x neutral density filter, two Nikon Speedlight SB-800 flashes, handheld camera. Hungary, May 2010.
Flash Sync
The maximum flash sync speed is the fastest shutter speed at which the entire image sensor can be illuminated by the flash pulse. Most modern DSLRs have a maximum flash sync speed of 1/250 second, which is the fastest speed at which a camera has the first shutter curtain fully open before the second shutter curtains starts to close. When shutter speed is faster than sync speed, the frame is only partially open, because the sensor is covered by one curtain, or parts of both curtains, and a flash burst illuminates only part of the image.
Slow shutter speeds increase the exposure from ambient light and give a more natural feel to the image, but the risk of unwanted motion blur increases.
Then again, balancing ambient light with flash light creates interesting effects, as the Eurasian Hoopoe picture illustrates. The ghostly image of a bird flying, captured with a relatively long exposure, shows a flurry of motion, while the flash helped keep some of the details in sharp focus. I underexposed the ambient light on the main subject by 1–2 exposure values (EVs) and set the flash to 0.5 EV lower than the EV suggested by the light meter.
With long exposures, a flash can bring out sharp details. Eurasian Hoopoe (Upupa epops).
Nikon D700, 300mm f/2.8, 1/4 second, f/9.0, ISO 100, manual focus, 8x neutral density filter, two Nikon Speedlight SB-800 flashes, Gitzo tripod and video head. Hungary, May 2010.
The light hitting the birds comes from a flash, and the background is in ambient light. Green Honeycreeper and Clay-colored Thrush (Chlorophanes spiza, Turdus grayi).
Nikon D700, 300mm f/2.8, 1/2500 second, f/4.0, ISO 1000, manual focus, Nikon Speedlight
SB-800 flash, Gitzo tripod and video head.
Costa Rica, December 2010.
Speed of Flash Bursts
When flash power is manually reduced, the duration of a flash burst diminishes along with the light intensity. This can be very useful when you set your exposure to be longer than the sync speed and freeze your subject within the short duration of the flash burst. The duration ranges of the flash burst in a Nikon SB-800 flash (and most shoe-mount flashes) are shown in the following table.
Flash burst |
Power |
1/1050 second |
At M 1/1 (full) output |
1/1100 second |
At M 1/2 output |
1/2700 second |
At M 1/4 output |
1/5900 second |
At M 1/8 output |
1/10,900 second |
At M 1/16 output |
1/17,800 second |
At M 1/32 output |
1/32,300 second |
At M 1/64 output |
1/41,600 second |
At M 1/128 output |
You can set your flash to a fractional power of 1/4 or 1/8 if you want to get some sharp details of moving birds. As an added bonus, with low power you can fire a series of exposures:
1/1 (full) power gives a series of one image
1/2 power gives a series of one image
1/4 power gives a series of three images
1/8 power gives a series of 6–10 images
Beyond this, with the flash at 1/16 power or less, the number of images is also determined by the power supply in your flash. If it is used with a powerful external power supply, a flash can produce more flashes than the number of images your camera can temporarily store in its buffer. So it could be said that the camera’s buffer limits continuous shooting more than the flash. Remember, though, that increased power heightens the risk of overheating, so keep an eye on your flash unit.
High-Speed Flash Sync
Most of the latest DSLR cameras and flashes allow flash to be used with all shutter speeds. In a traditional flash discharge, the light intensity increases rapidly to a peak and then trails off gradually. The duration of this light impulse at full power is around 1/1000 second. In high-speed flash (flat peak), the peak of the flash burst is weaker, but the flash gives out smaller bursts continuously from the time the front curtain opens to the time the rear curtain closes, and it lights the image evenly. Unfortunately, this means that the distance between the flash and the subject has to be reduced to maintain the same light intensity as in a situation in which the flash is used at full power to light a subject that is farther away. In bird photography, where it is seldom possible to get as close to the subject as high-speed flash requires, the flash has to be dismounted and placed close to the subject. In action photography the challenges are multiplied by the fact that to fire a series of exposures, you need to reduce the flash power as previously described. This results in a further decline in light intensity, requiring even closer proximity to the subject.
You should note that high-speed flash does not freeze movement in the same way as normal flash sync; instead, the camera’s shutter speed freezes the action. As long as there is no motion blur from ambient light, flash sync can produce a sharper image at 1/250 second shutter speed, because a flash impulse can be 1/10,000 second.
Front or Rear Curtain Sync
Curtain sync with a slow shutter speed and ambient light freezes movement but leaves motion blur in the image. Front curtain sync fires the flash at the beginning of the shutter duration and leaves trails ahead of the moving subject, whereas rear curtain sync fires the flash at the end of the shutter duration and leaves motion blur trailing behind the moving object. Trying to create motion blur with normal flash sync results in a rather messy general murkiness, which can also be a desired effect.
Augmenting Flash Intensity
Increased flash speed means reduced light intensity, which makes it necessary to dismount the flash and place it closer to the subject. To operate the flash, you need a transmitter attached to the camera hot shoe and a receiver attached to the bottom of the flash, or you can use another flash (slave flash). This can be done only in prearranged settings, for example if the flash or flashes are placed near a branch where you expect a bird to land. This method is out of the question when photographing subjects whose actions cannot be predicted. Also, when the flash is dismounted, flash systems communicating via infrared light will not function if they don’t detect each other. A radio wave system is a better option.
Since flashes are optimized to lenses up to 200mm, and bird photography mainly requires lenses between 300mm and 500mm, most of the flash light is wasted, and at the same time you are handicapped by insufficient light. Fortunately, there is a sensational invention to produce parallel light rays, first designed in 1818 by Augustin-Jean Fresnel, who realized that instead of using a gigantic and cumbersome convex lens, adhering bits of the bulging part of the lens on a substrate could achieve the same effect. Commercial Fresnel lenses mounted on flashes can double the light intensity when used for short distances, but there is an even better solution: large Fresnel lenses that were used in old overhead projectors. By cutting out a 12x14 cm (4.7×5.5 in) piece from the middle and placing it in front of the flash at a suitable distance, you can increase the efficiency of your flash by three stops, up to a distance of 8 m (26.2 ft)!
The numbers speak for themselves. The light intensity of a mounted flash at 1/8 power at ISO 1000 is amplified by 4 stops, making a 1/2500 second shutter speed possible at a distance of 8m (26.2 ft) in any ambient light conditions. This way the light from a shoe-mounted flash hits a surface smaller than the angle of a 400mm lens.
The best way forward in flash photography is through trial and error.
Fast action in low light—without flash, very little in this Great Reed-Warbler image would have been sharp (Acrocephalus arundinaceus)
Nikon D700, 300mm f/2.8, 1/160 second, f/9.0, ISO 250, manual focus, Nikon Speedlight SB-800 flash, Gitzo tripod and video head, floating blind. Hungary, May 2010.