If you're up to date on your photography history, you'll be aware that some of the stuff we used to have to do to get artificial light was basically the same as setting off fireworks next to your camera to capture the photos. Quaint as that feels, this is still the reality for high-speed photographers... If you want a swift way to kill yourself with photography equipment, the high-voltage flashes used to stop fast-moving objects is an easy way to go.
Let me explain. When we're talking about 'high speed' photography, we're not talking about the time it takes to trigger a flash. With a good high-speed flash trigger, you can go from trigger event (say, a laser beam being broken, or a loud enough sound) to strobe flash in a matter of microseconds.
What's the deal with high-speed photography
The challenge lies elsewhere: If you're trying to take a photo of something that moves very quickly indeed—say, a bullet—you need a very short burst of light. Now, what photographers traditionally think of as a very short burst of light—like the strobe from your studio flash—is actually a very long burst.
The problem is this: A standard .22 bullet has a muzzle velocity of 340 metres per second. So, if your very high-end camera with a shutter speed of 1/8000 second were to try and capture this bullet in flight, you'd be out of luck. Even at 1/8000 second, your bullet will travel 4.2 cm / 1.6 inches. That means you get a tremendous amount of blur in your photo — you certainly couldn't stop it.
So, what is a poor photographer to do? Well, a flash has a much shorter duration. A PC Buff Einstein (known to have a very short flash duration) will be about 1/13,000 second—but, when translated to our flying bullet, we're left with a blur again—2.6 cm / 1 inch is still a streak of blur. That's no way to stop a bullet, photographicaly speaking.
Even really short-duration strobes—like a Nikon SB-80DX at its lowest power output—has a duration of 1/22,000 second. Impressive, but no match for our trusty bullet — 1.54 cm / 0.6 inches. That's more like it, but still results in a rather blurry image.
So, what's a poor high-speed photographer to do? Well, Harold Edgerton, who was the father of high-speed photography, used an 'air gap flash'. If that sounds fancy, trust me—it really isn't. Imagine an electrode and a cathode, with a spark jumping between the two. In essence, you've got lightning—yes, real lightning—happening in your photography. It isn't difficult—anyone with a basic knowledge of electronics can build one—but it's incredibly dangerous. As in, could-very-well-kill-you-type-dangerous. We're talking at least 20,000 volts to create a spark that's bright enough to use for photography.
There are some slightly-less-likely-to-kill-you solutions out there, but they cost the earth: Upwards of $2,000 for basic short-duration strobes. Interesting, yes, but you'd really have to love high-speed photography to lay down that sort of money to embrace your hobby.
Is there a safe way to do short-duration flashes?
The solution, it seems, might be in technology. The clever lot over at Vela Labs have come up with a device they call the Vela One. It's not available to buy yet, but a Kickstarter campaign is aiming to rectify that situation.
To solve the 'this thing might kill you' and the price-tag issue, they're using LEDs designed for architectural use (i.e. mega-bright LED bulbs), and then they blink them very, very briefly.
By dumping a ton of power (in fact, 2000 times what they are designed for) into the LEDs for a brief period of time, they're able to get a lot of light out of the LEDs, for a very brief burst. How brief? Well, guys at Vela Labs claim it can be done in 1/2,000,000 of a second—which translates to 0.017 cm—or about twice the width of a human hair. To a photographer, this means pin-sharp photos, even of objects of moving at high speed.
Of course, this doesn't come for free: The cost of super-brief flashes of light is brightness. That is true for an air-gap flash, but also for the Vela One; but it looks as if the One offers a pretty good trade-off between flash duration and brightness. The photos speak for themselves.
At £550, it's not cheap, but it's a lot more affordable than some of the other high-speed options out there (although there's a VIP Early Bird offer of £400, but you need to be quick with only ten available)... And at least it's unlikely to kill you as you use it, which I find is always a feature I look for in most of my photographic kit.
The results? Well, let's take a look:
If you want the Vela One to exist, you'll have to head over to Kickstarter, and be quick about it, too. The campaign ends in only 22 days, so get a wriggle on!