An Online Guide - Part 3:
Exposure and Light
If your camera and multiple flashes support TTL flash metering, your exposure can be determined automatically. But I prefer to set my flashes manually and determine exposure with a flash meter, for several reasons:
Multiple manual flash requires the use of a flash meter. I like the new Minolta AutoMeter V-F (this replaces my IV-F), which is compact and doubles as an incident meter (B&H $220). A new meter that I like from Sekonic is the L-358 (B&H $200). A simple incident flash meter is all you need.
Your flash meter should have a "non-cord" mode. In this mode, you depress the trigger button on the meter, and then any flash that fires in the next 60 seconds will trigger the meter to take the reading. The alternate "cord" mode requires that you connect the meter to the flash via a PC socket, which many hotshoe flashes don't have..
Be sure you know how to correctly read your meter! Most give exposures to the nearest tenth stop, but you have to know how to decipher the display. Minolta and Sekonic meters give you "full" f/stop readings (5.6, 8, 11, etc.) plus a smaller number that represents 0.1-stop increments (other meters indicate this graphically). If your meter tells you, "f/11 and nine-tenths of a stop," that essentially means f/16. This is one situation where the "fine print" is important!
Guide Number calculations are a nightmare with multiple flashes, and not recommended.
Finally, some reciprocity failure can occur in films at these very short flash durations, which can lead to underexposure. And meters and cameras vary as well. So its best to examine some test rolls or digital captures to calibrate your results.
Depth of Field and Focusing Distance
After you get up close and personal with hummingbirds, one thing becomes abundantly clear: theyre tiny! The smallest hummers you're likiely to encounter in North America are barely three inches from the tips of their bills to the ends of their tails and thats including a relatively long bill. (The world's smallest bird is the Bee Hummingbird, just over 2 inches!) Frame-filling shots of these birds approach the realm of telephoto macro photography. As a result, depth of field is very limited.
To counteract this, shoot at apertures as high as f/16 to f/32 to get most of the bird in sharp focus. Again you must balance the conflicting needs of high flash power for depth of field versus low power to stop motion.
Iridescence Capturing the Light
One of the most striking features of hummingbirds, and the one youre sure to want to capture on film, is iridescence. Iridescence results from microscopic structures that break apart light and strongly reflect back only certain wavelengths. When light strikes at just the right angle, iridescent feathers appear to glow brilliantly and with very pure colors. The color may vary with the angle, and if the angle between viewer and light source is too great, it might simply appear black.
Many male hummingbirds, such as the Ruby-throated Hummingbird, have iridescent gorgets (throat feathers). Some species, such as the beautiful Broad-billed Hummingbird, have iridescent feathers over much of their bodies.
Lighting position is crucial to capturing this color on film. Basically, some of the lights should be fairly close to the lens axis. If the light is too far off axis, the iridescence will be diminished or not visible. On the other hand, some light from the sides will help reveal the shape of the subject.
In many ways this is like studio portrait work, with special consideration for iridescence. A single light on the camera produces a very flat look (but usually shows the iridescence). Multiple lights off-axis reveal the shape and produce a more interesting look. I often position one strobe aboveand somewhat behind the bird as well; this is like a "hair light" or rim light, and helps visually separate it from the background.