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Demystifying Hi-Sync (HS) and High Speed Sync (HSS) Flash

Demystifying Hi-Sync (HS) and High Speed Sync (HSS) Flash

by Michael Clark

Updated November 2018

This award-winning image of world-class whitewater kayaker Rafa Ortiz, created using two ELB 1200 battery-powered strobes with Hi-Sync technology, shows the incredible power of this cutting-edge lighting technique. Exposure Info: 1/2500th sec @ f/5 and ISO 500.

Since the dawn of photography there have always been technical limitations that restricted how and where flash could be used to enhance an image. In the last few years, there have been a slew of innovations with different flash technologies that have opened up never before possible options. These advanced high shutter speed sync flash techniques are often misunderstood. Here in this blog post the aim is to demystify and define the various flash technologies that allow us to shoot at shutter speeds higher than the standard flash sync speed of modern DSLR and mirrorless cameras.

Hi-Sync is the result of an optimized flash tube and remarkable technology built into the Skyport Transmitter PRO.

Overview of Flash Sync with Focal-Plane Shutters

Overview of Flash Sync with Focal-Plane Shutters

All flashes, no matter what size or shape, work by storing up an electrical charge and then emitting that charge as a light source through a flash tube.

When the flash is triggered the electrical charge is dumped into the flash tube and ignites a gas. The gas is ionized and thus releases a flash of light. Hence, the flashes we use these days are just a modern version of the old time flashes used a century ago where photographers basically ignited flash powder to create light. We are still just igniting a chemical substance. The only difference now is that we can control the amount of light emitted by the flash electronically and with incredible accuracy. How modern flashes work is simple in theory but complex in execution.

The focal-plane shutter incorporated into most modern DSLRs is composed of two separate parts, the first curtain and the second curtain. When you press the shutter release the first curtain opens and then the second curtain closes according to the selected shutter speed. The time gap between the first and second curtain is the shutter speed.

For longer shutter speeds, like a one second shutter speed for example, the first curtain opens and the second curtain closes after the one-second time period has elapsed. In this case, the entire sensor is exposed to the light between the opening of the first curtain and the closing of the second curtain. For shorter shutter speeds, like a 1/1000th second shutter speed, the first curtain starts to open and the second curtain follows shortly thereafter before the first curtain has made it’s way across the entire sensor. This results in a narrow slit of light that moves over the sensor, thereby creating a very fast shutter speed.

What is Flash Sync?

What is Flash Sync?

The “flash sync” is how the camera synchronizes with the flash so that the light emitted by the flash is recorded on the imaging sensor.

This animation shows the first curtain of the shutter opening and it is followed by the second curtain, which ends the exposure. Notice that the cameras sensor is full exposed for a brief moment. The fastest shutter speed at which the sensor is fully exposed at one time is the flash sync speed. For this camera that speed is 1/200th second. For other cameras, the flash sync speed can vary from 1/125th second up to 1/320th second depending on the camera model.

When shooting at higher shutter speeds, as shown here in this animation, the second curtain drops before the first curtain has reached the bottom of the sensor. Thus at higher shutter speeds than the flash sync speed the entire sensor is never fully exposed to the light at any one given moment. 

At even higher shutter speeds, in this case at 1/1000th second, the first and second curtain of the shutter create a moving slit of light that flows down the sensor. The higher the shutter speed the smaller this slit and the faster it moves across the surface of the sensor.

When shooting with flash at higher speeds than the cameras flash sync speed a black bar appears in the image, which is technically the shadow of the second curtain closing. At very fast shutter speeds, the second curtain closes before any light from the flash gets to the sensor, resulting (as shown above) in a black image.

The highest flash sync speed of any camera is the fastest shutter speed at which the entire sensor is exposed completely to the burst of light, as shown in the animation above. For some DSLRs and mirrorless cameras the flash sync speed is 1/200th second while others go up to 1/320th second. As an example, with my Nikon DSLRs, the top flash sync speed with strobes is 1/250th second. This is the fastest shutter speed where the entire sensor is exposed to the light all at once. With shutter speeds higher than 1/250th second, the entire imaging sensor is not exposed at any point, which is why you see a black bar in the bottom of the frame if you try to shoot at a shutter speed above the standard flash sync. That black bar is the shadow of the second curtain closing.

This portrait of a fly-fisherman was captured with a Hasselblad H5D medium format digital camera using a leaf shutter, which can sync with flash at every shutter speed. Medium format cameras have traditionally been the go to option when needing to sync with flash at high shutter speeds because they have a completely different shutter mechanism. The strobe used for this image was an ELB 1200 with the Action flash head. Exposure Info: 1/800th sec @ f/5 and ISO 100.

Some medium format cameras have leaf shutters that are built into the lens, and which work differently than the focal-plane shutters in DSLRs and mirrorless cameras. These shutters, which close with a central iris type shutter mechanism built into each lens, allow the camera to sync at all shutter speeds (in some cases up to 1/2,000th second) with no clipping of the flash. Medium format cameras with leaf shutters have traditionally been the go to option for professional photographers seeking out higher flash sync speeds than those available on 35mm cameras. While these medium format cameras are still a great option for photographers needing to sync with flash at high shutter speeds, both HS and HSS flash techniques now allow us to gain the benefit of faster flash sync speeds without the massive expense of purchasing a medium format camera.

Why do we need Hi-Sync (HS) and/or High Speed Sync (HSS) Flash?

Why do we need Hi-Sync (HS) and/or High Speed Sync (HSS) Flash?

For photographers, especially those working outdoors, the 1/250th second flash sync speed represents a huge limitation. When shooting with strobes, the aperture controls the brightness of the light on your subject and the shutter speed controls the brightness of the background. Hence, if your subject is overexposed you stop down the aperture. If your background is too bright you can choose a faster shutter speed to darken the background or a slower shutter speed to brighten the background. When shooting outdoors, in broad daylight, being restricted to a shutter speed or 1/200th or 1/250th second means that quite a bit of flash output (Watt-seconds) is required to overpower daylight. By accessing higher shutter speeds, we can overpower daylight with less flash power (or from farther away) and we also have complete freedom to use whatever shutter speed and aperture combination we want with flash.

The main reasons to use HS and HSS flash technologies are:

• A high shutter speed will freeze the action.
• The ability to overpower the sun with less flash power and lighter gear.
• The ability to capture images using flash with a large aperture, thereby creating a narrow depth of field.
• The ability to darken backgrounds using a high shutter speed.

Additionally, Hi-Sync (HS) specifically also allows us to overpower the sun when the flash head is quite far from the subject. How far the flash head can be placed depends on the power output of the flash and the light modifier used on the flash head.

This image was created using two Elinchrom ELB 400 battery-powered strobes and two HS flash heads. The lighting was set up in a light trap scenario with the two flash heads pointed at each other and the skier, Zach Vanderlei, snowboarded through the middle of the light trap. Because the ELB 400s are so light, my assistant and I could easily ski around Angel Fire Resort with both the lighting and camera equipment. Exposure Info: 1/6400th sec @ f/5 and ISO 250.

Working with both HS and HSS flash technologies opens up new doors creatively allowing for full control over the final image when using flash.

Comparison: Hi-Sync (HS) vs. High Speed Sync (HSS)

Comparison: Hi-Sync (HS) vs. High Speed Sync (HSS)

As of this moment, the two predominant technologies on the market that allow for working with flash above the normal flash sync speed are High Speed Sync (HSS) and Hi-Sync (HS). Let’s discuss each of these in detail and explain how they work.

High Speed Sync (HSS): High Speed Sync is a technology originally invented by Nikon and Canon for their line of Speedlights, but is also used by a few strobe manufacturers. High Speed Sync works by continuously pulsing the flash at incredibly high speeds creating a stroboscopic effect that illuminates each section of the shutter slit as it moves down the sensor. Because it has to output so many pulses of light, creating essentially a continuous light source for a brief period of time, the actual light output of the flash is massively reduced.

High Speed Sync works by firing the flash at low power thousands of times per second, which basically creates a continuous light source. The pulses of light illuminate the entire image as the shutter slit, created by the first and second curtain, passes over the sensor. High Speed Sync creates a very even distribution of light over the entire sensor with no gradation.



The upside of HSS is that it creates very consistent lighting across the entire image. The downside is that because the flash is outputting so many bursts of light in such a short period, the flash has to be fairly close to the subject. The light output also decreases with faster shutter speeds. Even so, since HSS technology is usually paired with TTL technology, it works very effectively and is also incredibly easy to use.

This portrait of a whitewater kayaker was created using one Elinchrom ELB 500 battery-powered strobe in HSS mode with the TTL engaged. The beauty of HSS, and especially with TTL, is that you can quickly get an accurate exposure at any shutter speed and aperture setting and then move over to manual exposure flash mode and tweak the lighting as needed. The HSS automatically compensates if you change your shutter speed. Exposure Info: 1/4000th sec @ f/2.2 and ISO 100.

For wedding, fashion or portrait photographers, who generally have the flash close to their subject, HSS is an excellent option. The Elinchrom ELB 500 TTL is a perfect mix of power and portability with HSS and TTL technologies built-in. For those that need more versatility, Hi-Sync (HS) is slightly more versatile.

Hi-Sync (HS): Hi-Sync is Elinchrom’s perfected version of HyperSync, which works in a completely different manner than HSS. To allow for the best results, Elinchrom has optimized the flash tube in the HS flash heads and they have also dialed in the timing exactly for their strobe units into the Skyport Transmitter PRO transceiver so that it works flawlessly. In short, Elinchrom has perfected Hi-Sync (HS) on a level that no other strobe manufacturer can match. Because of this, the HS works at any and all power settings on the ELB 400 and ELB 1200 battery-powered strobes when using the respective HS flash heads.

Hi-Sync works by triggering the flash before the camera shutter actually fires. As you might imagine this is incredible technology that relies on extremely precise timing. HS uses only a slice of the light emitted by the flash. The higher the shutter speed, the thinner that slice of light becomes.

Hi-Sync technically triggers the flash before the camera shutter fires and uses a normal flash mode. HS works best with slower flash durations so that the transmitter can sync up the timing. When used with flash units that have a faster flash duration it is much more difficult, if not impossible, to time where and how the slice of light is taken out of the flash curve. Hence for the best results with HS, using the HS flash head for your ELB unit is highly recommended.

When using HS a gradation like that shown here is common. With Elinchrom’s optimized Hi-Sync technology the ELB 400 has very little gradation. Because of the larger flash output of the ELB 1200, the gradation is much more noticeable but it is also very easy to correct in post-processing. Also, depending at what power setting the strobe is set to and which shutter speed is used there will be varying amounts of gradation.



In my testing so far with the Skyport Transmitter PRO and the new ELB400 HS flash heads, which have a flash duration of 1/550th second at full power, there is very little gradation that I can see in my images all the way up to 1/8,000th second. When using the ELB 1200, the gradation is more apparent. Regardless, this gradation is incredibly easy to correct in the post-processing.

HS technology is a godsend for sports, action or adventure photographers because it offers a reliable way to shoot with high shutter speeds and work with strobes from considerable distances. Any photographer photographing anything that moves, either inside or outside of the studio, would reap the benefits of using Hi-Sync.

Using two ELB 1200 packs with HS Heads, I was able to overpower the available light with the strobes placed over 100-feet away while capturing Kai Lightner climbing Chain Reaction (5.12c) at Smith Rock State Park. The lighting really helped to amp up the drama of the final image. Exposure Info: 1/800th sec @ f/5.6 and ISO 800

The benefits of Hi-Sync include the ability to sync at shutter speeds above your normal sync speed, freeze motion, and the ability to overpower the sun from phenomenal distances. Hi-Sync can also be used to create a narrow depth of field using large apertures. Hi-Sync is fairly easy to use once you have it dialed in for your camera, though it is not as easy to use as HSS with TTL.

The downside with Hi-Sync is that a light meter can’t be used to determine the correct aperture for exposure. At some point perhaps this issue will be solved but for now using the Histogram and the rear LCD display on the back of the camera will be the best guide for exposure settings.

Hi-Sync is by far the best option for those who need the highest light output from their flash when shooting at shutter speeds above their flash sync speed. Hi-Sync also offers more options than any other flash technology because you have more light output at your disposal. Because the ELB 400 and the ELB 1200 have multiple flash heads to choose from, and because the ELB 1200 has a dock that turns it into a studio strobe, these two battery-powered strobe are incredibly versatile.

For those jumping into HS with either of these kits, I recommend the HS and Action flash heads to have the ultimate versatility. When using higher shutter speeds, like those above your normal flash sync—i.e. 1/400th second up to 1/8000th second, the HS flash head is the one to work with. When using shutter speeds at or below your normal flash sync shutter settings—i.e. 1/250th second down to 30 seconds, the Action head is then the preferred option because it has a very fast flash duration. In the former case, the shutter speed will stop any motion and in the latter case, the fast flash duration will freeze the motion of the subject.

Hi-Sync uses much less power than HSS because the flash head is firing normally. With Hi-Sync it is also possible to turn the power down and continue to use a fast shutter speed. Hi-Sync, in my opinion, offers more versatility than any other flash option on the market.

Using one ELB 1200 pack with an HS flash head allowed me to freeze the motion of the waterfall and use a relatively shallow depth of field for this portrait of world-class whitewater kayaker Rafa Ortiz. Exposure Info: 1/2500th sec @ f/5.6 and ISO 400.

HS is ideal really for any genre of photography, but it works especially well with those scenarios where you need to get a lot of light to your subject. An obvious example of that are the adventure sports images included with this blog post where the strobes were placed at a distance from the subject. But even when capturing portraits, often we want to feather the light off the subject with a big light modifier and a lot of diffusion and this means a lot more light output from the strobe is required—and this is where the ELB 1200 excels. Of course, because HS is so efficient, this also means we can overpower the sun from twenty-feet away with the ELB 400 and up to sixty-feet away with the ELB 1200 when using a very efficient light modifier like the High Performance reflector from Elinchrom. If you need a strobe that can stop motion with fast flash durations at full power and also sync at high shutter speeds then the ELB 400 and 1200 are the best options on the market bar none.

Using the ELB 400 and ELB 1200 in Tandem

Using the ELB 400 and ELB 1200 in Tandem

The Elinchrom ELB 400 and ELB 1200 compliment each other incredibly well. For a lot of my work, I often use the ELB 400 to compliment my ELB 1200—and also to save some weight. When capturing action, I may have one ELB 1200 as the main light and an ELB 400 as a secondary light. Similarly, when working on location capturing portraits, I almost always use the ELB 1200 as my main light, which is usually feathered off, in tandem with a few ELB 400s that are used either as rim lights or to light the background.

Together, the ELB 400 and 1200 offer the ultimate versatility for location lighting whether shooting in HS mode or in normal flash modes.

Using one ELB 1200 pack and one ELB 400 pack, both with their respective HS flash heads, I was able to travel relatively lightweight and still pack enough light output to create a light trap for this mountain biking image. The lighting helped to create a very stylized image straight out of the camera. Exposure Info: 1/2000th sec @ f/5.6 and ISO 400.

Using HS and HSS Together

Using HS and HSS Together

Amazingly, HS and HSS can be used together to light a scene. As in the image below, I used an ELB 1200 in HS mode as the main light in front of the boxer and an ELB 500 TTL in HSS mode for the rim light. The Transmitter PRO figured out the timing for both the HS and HSS strobes simultaneously. As this image shows, using HS and HSS together might offer the best of both worlds and the ultimate versatility.

Using one ELB 1200 pack with an HS flash head as the main light up front and one ELB 500 TTL pack using HSS for the rim light behind the boxer, I was able to combine both HS and HSS to create this multiple exposure image. Exposure Info: 1/2000th sec @ f/5.6 and ISO 100.

In the end, both HSS and HS technology have their place and can be very effective for a variety of scenarios. At this point Elinchrom is the only strobe manufacturer that offers both options and has optimized both HS and HSS to be as efficient as possible—and they also have the transmitters to allow for both HS and HSS to be used simultaneously. It is quite an exciting time to be working with flash.

About Michael Clark

About Michael Clark

Michael Clark is an internationally published adventure photographer specializing in adventure sports, travel, and landscape photography. He produces intense, raw images of athletes pushing their sports to the limit and has risked life and limb on numerous assignments to bring back stunning images of rock climbers, mountaineers, kayakers, mountain bikers, big-wave surfers, sky divers and many other extreme sports athletes, often working in remote locations around the world. He uses unique angles, bold colors, strong graphics and cutting-edge, dramatic lighting techniques to capture fleeting moments of passion, gusto, flair and bravado in the outdoors. Balancing extreme action with subtle details, striking portraits and wild landscapes, he creates images for editorial and advertising clients worldwide.

A sampling of Michael's clients include Apple, Nike, Nikon, Adobe, Red Bull, Microsoft, Nokia, Patagonia, New Balance, Gatorade, Elinchrom, National Geographic, Sports Illustrated, Outside, Men's Journal, and The New York Timesamong many others. He has won numerous awards for his photography and Digital Photo Pro proclaimed Michael a "Master of Adventure" Photography” in their 2011 Masters issue.

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