Hype – and hyper: A discussion on hypersynch by John Duder

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We’re coming up to the season for inventors to sell us solutions we’ve never thought of to problems we didn’t know we had, all of them leading us to spend money on presents that won’t get used… I remember, somewhere in the Seventies, buying an Autochop for my Mum. I’m not sure that it ever got past a trial outing, but it may well still be in my sister’s kitchen cupboard.

And that brings me to the point for today – it’s called hypersynch (most people spell it without the final h, but they may well also spell flak with an added c, neglecting where the word came from), and it’s about synchronising flash at high shutter speeds: but it doesn’t need the multiple sequential flashes of high speed synch, where a flashgun fires many times at very short flash durations, ensuring exposure of all parts of the frame even though the shutter curtains are not open all the way across the frame at any time. Instead, it synchronises the high shutter speed with the brightest part of a flash.

To some extent, both HSS and hypersynch are, for me, solutions in search of a problem – I don’t have a need for flash and fast shutter speeds in most of what I do. Those who shoot a lot of action in relatively controlled and contrived locations may see it as essential for their images, but it’s not essential for 99% of my pictures. I have a flashgun that’s capable of HSS, although four years of ownership haven’t seen me use it in anger.

But let’s assume that you want to take pictures with flash at high shutter speeds, and don’t have an HSS flash unit. It definitely can be done, and there are a good few YouTube clips telling you how marvellous it is, and suggesting which camera and flash unit you have to use. After having it demonstrated to me by a friend who used a Yongnuo flash and trigger, I tried it with my Godox HSS trigger unit, coupled to an Andoer trigger set and an elderly Sunpak flashgun.

Coupling the Andoer unit directly to the camera leads to the cutoff that you’d expect.

The Godox trigger unit sits in the flash shoe of my Alpha 7, and the Andoer trigger sits in the hot shoe on the top of it, triggering the Sunpak sitting atop an Andoer receiver. I bought the trigger units ten years ago or so, to allow me to use multiple small flashguns in a building that (very sadly) I no longer have access to. The flashguns seemed to be lying around, having been bought at various points over (many) years.

And, quite amazingly, it worked. In one sense, the how of it can be explained by looking back at an old textbook that explains M synchronisation with old-fashioned single use flashbulbs – the shutter opens and closes during the time that the flash is producing light. The big difference is that a flashbulb burns for a significant fraction of a second, maybe around 1/30, and electronic flashes have a much shorter duration. It’s just a matter of timing!

And this is where it gets interesting. A camera fitted with M synch (I have several, but it’s not something I’ve seen on any recent camera) fires the flash ahead of the shutter, so that the bulb achieves full brightness before the shutter opens. This contrasts with X synch, which fires the flash when the shutter is fully open, so that the flash fits into the shutter-open period, rather than the shutter exposure fitting into the illumination period. Diagrams may make this clearer!

So the question is, if the camera can’t fire the flash until the shutter is open, what’s going on to allow the flash to ‘wrap around’ a high shutter speed? It’s clearly something going on in the Godox trigger unit, but what? It can’t do anything until I press the shutter release. But when I attach the Andoer trigger direct to the camera and use a high shutter speed, I get the cutoff that all the textbooks say you get with a shutter speed higher than the camera’s fastest (conventional) flash synch speed. Anyone who understands what’s going on, please add a note to this article! (My best guess is that something in the complex link between the Godox trigger unit and the camera delays the shutter release – after all, there are a lot of extra connecting pins on the front edge of the gun, and inside the Sony hot shoe.)

The difficulty with anything as offside (or left field, as they say on the other side of the Atlantic) as hypersynch is that you need to either experiment, or use exactly the same kit as someone who’s already done it, or buy an off-the-shelf setup from Pocket Wizard or one of their competitors. Other than the proprietary systems, there are no guarantees, and that’s always tricky if you are contemplating the purchase of new equipment for a specialised technique. There aren’t any cheap ways through this unless you have some of the crucial parts in your outfit already.

I repeated the exercise with a different trigger set (an elderly Ommlite set) with the same results.

There’s a side-effect that may be of concern to you, because if you are using a flash that wasn’t designed to work this way, it won’t have the long, even flash that hypersynch needs. You may therefore get progressive, gentle shadowing along one edge, as that part of your image was exposed when the flash output was past its peak.

Back to basics – why use flash when there’s ambient light (and how)?

You may, of course, be wondering why you’d want to do this stuff at all, so let’s build it from the ground upwards. If you are shooting by existing light, there are times when you want to add a bit of light to the foreground – maybe you are taking a portrait against the light, and want to balance the foreground and background a bit. An obvious way is to use a reflector, but they are unwieldy, and you may need an assistant or two to keep it in position if there’s a breeze.

A next choice is obviously to add flash – compact, and theoretically simple to balance with the background light. I first read about this around 1969, when it was called ‘synchro-sun’ – possibly an early indicator of the way my photography would develop. I’m sure the first picture I saw was of a pretty blonde girl…

When you do that, you can control the exposure of the background with ISO, aperture and shutter speed. But for the flash exposure, only aperture and ISO have any effect, so you can use the shutter speed to alter the relative brightness of subject and background. Typically, you’ll want the fill light to be subtle, and a general rule back in the Sixties was to have the flash giving two stops less exposure than the ambient light requires. If you have an automatic flash gun that adjusts output, set it to give correct exposure for an aperture two stops wider than the one you are using.

The big limitation back then was the synch speed of the camera. While leaf shutters (most compact cameras, twin lens reflexes, and some professional cameras, like Hasselblad and Rolleiflex models) allow you to use any speed, focal plane shutters (most SLRs, all DSLRs and mirrorless) have a limit. These range from 1/30 for older and larger cameras, through 1/60 for modern horizontal-run cloth shutters, and 1/125 for many vertical focal plane shutters in film cameras, to 1/250 or 1/320 for the highest spec cameras.

Along came HSS flash units, in the relatively recent past. These are clever little gadgets that fire repeatedly during the time the shutter is open, and this gives even coverage across the frame, even though the shutter blinds are never open across the whole frame (because the rear curtain starts to move before the leading curtain has crossed the frame fully).

The disadvantage is that each individual flash in the series is rather less powerful than a single flash, requiring higher ISO, a wider aperture, or a closer subject to retain the same brightness. This is said to cost between one and two stops of power, and will definitely take a toll on your batteries!

Hypersynch allows you to use a single flash, packing more of a wallop than repeated flashes, but makes the synch quite tricky, as the flash has to go off just a fraction before the shutter starts to open, and so specialist triggers are needed. The whole shooting match was invented by Pocket Wizard, and the essence of it is that the trigger unit attached to the camera ‘uses special camera communication to trigger a normal flash before the first curtain opens. It can also eliminate the delay introduced by a typical radio trigger. The timing can be optimized for some flashes based on the user’s wishes.’ This will not work with your generic flash triggers on their own – but the good news (if you want to try it) is that everyone else seems to be copying what Pocket Wizard pioneered, and so a variety of advanced trigger units will allow you to use the technique.

Useful in the real world?

When might I want to use hypersynch (if I can remember how to do it)? Basically, when I need both to use fill flash and a high shutter speed – think in terms of a dancer doing a jump with a window behind. A slow shutter speed will allow a fain blurred image around the sharp flash-lit image, which isn’t generally desirable. For me, as I have that HSS Godox flashgun, HSS will be easier: but the friend who told me about the technique and set this whole article in motion has invested significantly in small but powerful flash units (think Godox AD-200, but without the HSS capability). He is somewhat older than I am, and finds that the size and weight of such units is preferable to a full portable studio lighting setup, and I can see the point.

You may want to play with the concept of hypersynch and applications simply because you enjoy trying different things (or like me, research it for the sake of telling others about it). I suspect, though, that the number of people for whom hypersynch is actually the best or the only solution is tiny: if you have the equipment to do it, you probably have the capability to use HSS, possibly with the same equipment, and that’s probably a simpler plug-and-play solution.

And there will be some special conditions where it’s the only viable solution: I think that would be where you need the power of full-house studio lights with mains power or portable power packs, and a high shutter speed to freeze action. I think…

One of the concepts I try to embed in the minds of people who attend my lighting workshops is that when you are using flash as the main source of light, exposure is controlled by aperture and ISO, and the shutter speed makes no difference, because the whole of the flash happens within the time that the shutter is open. With hypersynch, this ceases to be true, and increasing the shutter speed from 1/1000 to 1/2000 will require you to open the lens a stop to compensate. This means that even a powerful studio flash will require wider apertures and/or higher ISO settings.

A final warning. If you have old flashguns around, as I do, beware, ever, of attaching them directly to a modern digital camera. Some of them have very high trigger voltages – fine with a mechanically-operated electrical contact, but a disaster when mixed with an electronic circuit board. Use a remote trigger set whenever you want to play with old flashguns and modern cameras, or check THIS LIST carefully beforehand.