An Online Guide - Part 1:
High Speed Flash
Hummingbirds are some of the most colorful and delightful birdswonderful to watch, and fun to capture with your camera. This Online Guide will give you an introduction to professional techniques for photographing these flying jewels, and preview what you will learn in our Hummingbird Photography Workshops. But try these techniques with cautionhummingbird photography can be addictive!
Freezing a Hummingbird's Wings: High-Speed Flash
As hummingbirds hover at a flower or feeder, their wings can beat up to 80 times per second, which produces their signature hum. To the naked eyeand often to your camerathe wings are just a blur. One of the first questions I'm asked is what shutter speed I use to stop this super-fast movement.
The real answer is that the motion is frozen with high speed electronic flash (or strobe), not by a fast shutter speed on the camera.
You can photograph hummingbirds with a single flash mounted on your camera's hotshoe. But for professional looking results, you'll want to use multiple flashes mounted off the camera. How many should you use? That depends on your style and resources.
Three or four is a good starting number. I sometimes use five or six because, as you'll see, you usually need separate strobes on the background. The good news is that you can use fairly simple and inexpensive hotshoe flashes (e.g. Vivitar or Sunpak) as I'll explain below.
Controlling Flash Duration
A typical hotshoe flash puts out a very fast "pulse" of light. But how fast is fast? To freeze all motion in a hummingbird's wings, you need a duration as short as 1/5,000 to 1/20,000 of a second (50-200 microseconds).
At full power, a typical hotshoe flash has a duration of about 1/750 to 1/1,000 s, which is too slow for our needs. However, today's variable power flashes have a key feature that we can exploit: as you decrease the power, the flash duration also decreases, roughly in line with the power.
For example, my Canon Speedlites have a duration of about 1/750 s at full and half power, and then the duration decreases by roughly half every time you reduce the power by one f/stop. The result is about 1/6,000 s at 1/16 power, and 1/10,000 s at 1/32 power. That's plenty of stopping abilityalbeit at the cost of reduced light output. (But we can compensate for that by using several flashes and moving them closer to the subject.)
There are two ways to get low power from a hotshoe flash: adjust the power manually (if your flash has a manual power setting), or use TTL (Through-The-Lens) automatic flash and move closer to the subject. I prefer to set the flash power manually, for more control. But let's take a look at how TTL autoflash works first.
Getting Short Flash Durations with TTL
TTL flash metering requires a camera and flash that can communicate with each other. When the camera senses through the lens than enough light has reached the subject, it signals the flash to quench its output. Hotshoe flashes can accomplish this extremely quickly via a component called a Thyristor, which immediately cuts off power to the flash tube and stops further light output.
If you're familiar with the Inverse Square Law for light output, you can see why moving the flash closer to the subject in TTL mode reduces the flash duration. The Inverse Square Law says that each time we cut the distance in half, the light output increases by 22, or a factor of 4. For photographers, that translates to a gain of two f/stops.
Since the camera senses the need for less flash output as you move closer, the TTL system will automatically reduce the powerand thus the duration. This works as well with older, pre-TTL automatic flashes, like the Vivitar 283, which measures light reflected from the subject via a photocell on the front of the flash instead of through the lens.
Short Durations with Manual Flash
While TTL flash at close distances gives you short flash durations, it has two disadvantages for hummingbirds:
For these reasons I prefer to set my flashes manually to a low powerand motion-stopping abilityof my choosing. In that case, there are two features to look for in flashes for this type of work:
Not all flashes allow you to set the power manually (even though they may adjust it internally in TTL mode) so check for this feature. And you want to start with a fairly powerful flash, so that you can set it to low power and still have enough light.
I'll have more to say about choosing flashes in Part 5. But now let's learn about how to use them for humminbirds. Next ...