How Does High Speed Sync Really Work?

How Does High Speed Sync Really Work?

How does High Speed Sync work with flash units?

High Speed Sync is more simple than you may think. In a conventional flash, when the shutter speed exceeds the flash sync speed, it can end up leaving a gradient in the final image. HSS works by firing short pulses from the flash, almost like a continuous light and keeps the image looking crisp and clean

What Is High Speed Sync?

With the latest addition into our Studio Flash Range, the Lencarta SuperFast Pro – we’re often asked by our customers, how exactly does High Speed Sync work? Is it just a useless feature or does it have real world benefits?

It’s summer now, which means the sun is shining (sometimes) and many photographers will be packing up their kits and heading outside. However ambient light, especially from the sun can cause problems with your finished image. This is often caused by harsh sunlight, so the photographer simply ups the shutter speed to reduce the effect of the sunlight, but when this is done without using HSS the shutter isn’t fully open, so only part of the image ends up lit with the flash.

The area that isn’t lit with the flash is darker than the rest – if the shot is taken in darkness there would be a black area at the bottom of the shot. When the shot is taken in sunlight, the area that isn’t lit by the flash is still there, but less dark.

But how can I get rid of this dark area?

Put simply, the easiest way to get rid of this gradient is to shoot with a HSS enabled flash head (with a HSS enabled triggers). Products such as the Godox AD200 (Which also has TTL functionalities) or our Lencarta SuperFast Pro. As mentioned, you will also need a HSS enabled trigger. We offer two – for Canon cameras, we find that our new WaveSync 2.4 Mach is the best option, with the large backlit LCD screen and easy to use system, this trigger is ideal for Canon users who only want a HSS trigger. For Canon/Nikon/Sony users who also want TTL functionalities – the WaveSync 2.4 TTL is your best option.

I’ve heard of Tail End┬áSync, is this the same?

No. High Speed Sync works by pulsing the flash at a very fast rate, making it almost a continuous light. At high shutter speeds the HSS mode will make the flash stay on for as long as the shutter is open. Tail End Sync (also known by proprietory names such as HyperSync) allows the flash unit to work normally giving you more flash power, but works by making the flash head fire a few nanoseconds before the shutter curtains begin to open, allowing the flash to be fully firing by the time the shutter curtains begin to move.

In short, HSS can be better than HyperSync because, whilst you’re getting less flash power, you’re guaranteeing a crisp image, whereas Tail End Sync normally needs full power flash to work. It can also vary from camera to camera, with cameras fitted with slow shutter actions producing unsatisfactory results. HSS on the other hand is universal and works irregardless of brand.

Does High Speed Sync have a studio use?

Realistically – if it does have a use in the studio then it’s minimal – it comes into its own outdoors, in bright light. However that isn’t to say never buy a HSS enabled flash head, as HSS enabled flash heads have Insulated Gate Bipolar Transistor (IGBT) technology in order for the HSS functionalities to work, and this usually has the side benefit of producing ultra fast recycling recycling, which allows you to take successive shots in very fast succession.

However if you’re in a studio that utilises natural or ambient light – you may see the same problems you may find in outdoor shoots, and in this instance High Speed Sync would be of benefit.

So whilst you may not need the functions of High Speed Sync inside a studio, apart from in certain situations, HSS enabled flash heads usually have loads of features that make it possible to freeze action.

Positives of High Speed Sync

  • HSS can produce a sharp, crisp image
  • Any HSS enabled flash head HAS to have IGBT technology, which means freezing action becomes so much easier

Drawbacks of High Speed Sync

  • The flash can never be full power due to a lot of the flash power being used to produce short quick pulses of light