Despite what people might tell you, or what you might read, you don’t need High Speed Sync (HSS) to freeze action! You don’t even need expensive strobes. You can do it today with a six-year-old flashgun! This is one of my favorite low budget photography hacks. Here’s how you do it…
A couple of years ago I desperately wanted to freeze action… I wanted to capture a tennis player mid-serve. I believed at the time that I would need to go out and buy myself, or hire, a complete new set of flash triggers and flash units, probably location strobes. We’re talking minimum £1,000 for a two-light setup. Minimum. Realistically you’re probably looking at more like £2,000. I didn’t have that sort of money to spend on a single project. Nor would I have wanted to spend it if I had it!
But after speaking to a LOT of people, and reading everything I could find, it turned out I didn’t need to spend anything.
There’s lots of talk about high-speed sync in the world of photography lighting. Firstly, let me explain exactly what it is:
Flash Sync Speed
On most cameras there will be a maximum flash sync speed. Normally it is 1/125 or 1/160, maybe max 1/200. Back in the old days it was much lower. The flash sync speed on my Canon AE-1 Program is 1/60.
What this number means is – the minimum amount of time that the camera requires to communicate with the flash unit. So, if we take the Canon AE-1 as our example, it takes the camera at least a 60th of a second (1/60) to communicate with the flash. Therefore, if you set the shutter speed any higher, 1/200 for example, the shutter will open and close before the flash has fired.
HIGH SPEED SYNC is a system which allows the camera and flash unit to communicate faster than that maximum sync speed, sometimes as fast as 1/4000 of a second. So if you DO have high speed sync, then you can use your camera to freeze action easily (although using flash off camera doesn’t necessarily carry this high speed sync with it, depends on your off camera flash triggers…)
With me so far?
Communication between camera and flash
There are several factors that determine the communication speed.
In order for the flash to fire at the precise moment when your shutter is open, several things have to happen in a short space of time. First you press the shutter release, the “take picture” button”. Then, as the camera is opening the shutter, the processor has to send an electronic signal to the hot shoe telling it to signal to the flash unit to fire at the same time.
Next the hot shoe has to pass that message onto the flash unit itself. And then the flash unit has to fire, and complete its flash cycle (light on, light off) before the shutter closes again.
If any of you have tried using a flash with a shutter speed higher than the maximum sync speed, you will have seen the results. Initially, when the shutter speed is a few stops over the flash sync speed, you’ll get the half of your image illuminated, and the other half dark.
This is because the flash has fired when the shutter was halfway through its cycle. In other words, the shutter had long since opened, and was already closing, when the flash finally fired. So, some of the sensor was obscured, and therefore didn’t benefit from the light. The shutter speed was too fast for the flash, it was ahead of the game and the flash couldn’t catch up.
Shutter Speed faster than sync speed
If you continue to increase the shutter speed up to 1/250 or 1/500, or even 1/1000, now getting way beyond the published maximum flash sync speed, after a few stops you will lose the flash altogether. Your image will look as if there was no flash there, despite the flash firing.
The shutter is opening and closing before the flash has even received the signal to get started.
As flash sync speeds are generally, even on modern cameras, somewhere around 1/125 or 1/160, it should be dawning on you that you will not be able to freeze action.
The speed of the action dictates how fast the shutter needs to open and close to prevent blurring when shooting action.
A car passing close to you at 100 mph will would probably require a shutter speed of perhaps 1/2000. To freeze an average person running, you’re probably looking at anything upwards of 1/800 (something like that, I’m just guessing! Feel free to put me right in the comments!)
So, if you want to photograph someone running, and freeze the action, whilst using a flash to create a desired lighting effect (or at night of course), then you somehow need to find a way around this problem.
And here’s the good news… there is a workaround!
As with all low-cost options, the workaround is far from perfect. As always, there are concessions to be made. But instead of needing tens of thousands of pounds worth of equipment, you can do this without spending more than a hundred.
Here’s how it works:
High speed sync specifically refers to the amount of time it takes for your camera to communicate with the flash unit. It doesn’t have anything to do with the speed at which the flash fires.
We can use this to our advantage – if we can get the flash to fire for a short enough time, and the camera to expose for ONLY that moment that the flash fires, then all we will see is what the flash has lit.
Are you following? If not, let me explain slightly differently – imagine you’re in a perfectly dark basement, and someone is walking towards you in the dark. You can’t see where he is, but you know he’s moving. You’re looking into the dark, trying to see him, but… nothing.
A slightly creepy analogy
Then the light flicks on for a moment, and you get an image of the guy at that exact moment, wherever he is in the room. Walking towards you, looking menacing!
The light then goes back off again after just a second, and you can see nothing more. But that image of the guy at that moment stays in your mind.
If we now swap your eyes for a camera… the shutter has been open the whole time the guy was walking across the room, but there’s not enough light to create an exposure without the light on. Then when the light flicks on, suddenly there’s enough light, and the camera registers an image. The light then goes off again and the camera “sees” nothing more.
That is exactly how the camera works… and if you can get your head around this then you are all good for essentially understanding all of photography.
One more time…
To summarize – in a world of complete darkness, you could have a shutter speed of 1/8000, or a shutter speed of 10 minutes, it won’t make a difference. You won’t see anything, because there is no light.
If your shutter is open for 10 minutes, in perfect darkness, then you flash a light on for a second, the camera will record an image for that second, and nothing else.
Therefore, if you can adjust the exposure to accommodate your flash settings, then you can create a situation where the only thing the camera “sees” is the moment your flash fires, even if the shutter is open for much, much longer.
And therefore…… if you can get your flash speed fast enough to freeze action (1/1000 or quicker), then you don’t need High Speed Sync!
Here’s the really awesome news – pretty much all flashguns can do this!
If you’re photographing in a fairly dark environment you can set the camera up to expose correctly for when the flash fires, and therefore only capture that brief moment of exposure, even if the shutter is open for much longer.
I will try to explain that a bit more clearly. If the shutter is open for one the second the camera, and your aperture and ISO correctly set for the ambient lighting conditions. Then your camera will capture everything that happens in that second, mash it all together, and you end up with a blurry image.
If, however, your aperture and ISO are set to a value that receives no image, just black, despite the shutter being open for one second, then you can fire a flash anytime during that second and the only thing that the camera will register is the moment when the flash fired. See the above analogy of the creepy guy walking towards you!
So, provided your flash unit only illuminates the scene for 1/2000 of a second or less, your shutter can be open from a whole second and movement still be frozen crisply and cleanly.
Your brain should be making the step to the next bit of this conundrum… How long does a flash fire for? It looks quick, but is it really?
The short answer to this is… it varies. But you can find out really easily.
Studio strobes are different from flashguns, or speed lights. They operate on different systems, and therefore behave differently.
As a very basic rule of thumb – the duration of a flash of a studio strobe is roughly uniform across the power output range, but can be slightly slower at LOW power.
Flash duration of a speedlight is the opposite – variable and much longer at high power, shorter at low power.
The flash duration of a flashgun is measured in what is called a T time. There are two values available – T .5 and T .1. You can almost always get hold of the T.5 time for any flash, the manufacturer will publish these, but the T.1 can be more difficult to track down. Which is irritating because that’s the number you really need.
You should be able to find the T.5 times in your flash manual, or online if it is not in there.
Here’s what the two terms mean:
T.5 time is the time it takes for the flash to build to the desired power level and back down again to 50%. So if you set your speedlight or flashgun to full power, the T.5 time how long it takes for it to reach full power and get back down to half of that power.
T.1 time is how long it take the flash unit to get to the desired power level and back down to 10% of that power. So, when set for full power, the T.1 time is how long it takes to go from 0% to 100% and back down to 10%. Much more useful when we’re talking about freezing action.
Some example T.1 times
These are surprisingly hard to find actually, but the amazing blogger Andy Gock has done his own tests of a few older model flashguns, and has published his own results in this amazing article – Actual Measured Flash Durations of Small Speedlight Strobes.
Here’s an example of Andy’s T.1 times for a Canon 580EX:
As you can see from these figures, if we’re taking 1/800 as our benchmark for freezing a human running, for example, then anything from 1/2 power and lower will do the job.
Let’s put together everything we’ve learned…
- You don’t need high speed sync to freeze action with flash
- Freezing action doesn’t need fast shutter speed
- You DO need a fairly dark environment, otherwise you’ll get double exposures
- The faster the thing you’re trying to freeze, the less power you can use
- But you still don’t NEED high speed sync to freeze action.
And to bring us right around full circle to BudgetProPhoto’s core philosophy… the above table is for a Canon 580EX flash gun, which you can pick up second hand for $100. Sometimes even less! I got one for £20 (about $27) off eBay a few weeks ago because eTTL was broken and you could only use it on manual…. I only use my flash on manual anyway!! BARGAIN!
To read about all of this info put into practice, and to see some real world examples of it in action, check out this article by Havelock Photography – How to Freeze Action With Speedlites
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Thanks for reading – from the BudgetProPhoto team.