High speed sync enough?

[NAwlins Contrarian]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses (which can sync at any shutter speed) in situations where you need to balance relatively bright ambient light with flash lighting on the main subject at large or moderate apertures?

In a thread in another forum (https://www.dpreview.com/forums/post/67209463), a user asked why Fuji doesn't offer leaf-shutter lenses for its GFX system. I suspect (and suggested) that the reason is that often HSS suffices. After all, today there are 600, 1000, even 1200 Ws monolights that feature HSS, and common lighting setups often involve more than one such flash. I realize that HSS reduces light output, and that modifiers like softboxes and umbrellas reduce it further.

But would, say, a kit with two or three Godox AD600Pro monolights allow you to light adequately and to your taste, where you have to balance with outdoor daylight, using HSS instead of X-sync or a leaf-shutter lens?

 

[Ed Shapiro]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses (which can sync at any shutter speed) in situations where you need to balance relatively bright ambient light with flash lighting on the main subject at large or moderate apertures?

In a thread in another forum (https://www.dpreview.com/forums/post/67209463), a user asked why Fuji doesn't offer leaf-shutter lenses for its GFX system. I suspect (and suggested) that the reason is that often HSS suffices. After all, today there are 600, 1000, even 1200 Ws monolights that feature HSS, and common lighting setups often involve more than one such flash. I realize that HSS reduces light output, and that modifiers like softboxes and umbrellas reduce it further.

But would, say, a kit with two or three Godox AD600Pro monolights allow you to light adequately and to your taste, where you have to balance with outdoor daylight, using HSS instead of X-sync or a leaf-shutter lens?

I used leaf shutter for many decades- back in the film days. I avoided focal plane shutter becasueif synchronization issues and fi lass fill requirements. Many large and medium format cameras a some 35mm modes had full-synch leaf shutters and the familiar X setting.

I am not sure if any current digital cameras have a full synch shutter although some will synch at somewhat higher speeds than prior modes- I might not be aware of such a feature. If you are experiencing difficulty in flas fill exposure and ratio control, HHS may be your only alternative.

My old method flash fill quick method was to expose for the flash and select a shutter speed to accommodate the daylight. In certain lighting conditions, it is impossible to do that with limited synchronization speed ranges.

The use of multiple flash out-of-doors as main or fill sources is possible but one or all of the lights have to synchronize. The placement and the number of ligh have more to do with your lighting strategy than synchronization issues.

If you can test out at least one speedlight or monolight with HHS and run some test, you will get a better idea of the feasibility of the system.

If you specify waht you inted to shoot with a multiple lighting system and what your planned lighting strategy is, I can be more specific as to power requirements, modifiers, softboxes, etc.,


Ed Shapiro- Commercial and Portrait Photographer. Ottawa, Ontario Canada

 

[Colin Creevey]

But would, say, a kit with two or three Godox AD600Pro monolights allow you to light adequately and to your taste, where you have to balance with outdoor daylight, using HSS instead of X-sync or a leaf-shutter lens?

I find it difficult to understand this statement. The way I read this statement is as follows.

If you had a kit of 2-3 Godox AD600Pro AND you don't have a leaf shutter AND you need to balance the light with ambient outdoors THEN would the kit adequately light to your taste.

If my understanding of your statement is correct, then in my case, yes HSS would be fine for me most of the time. However, your use case and workflow may different from mine. Regardless, I prefer keeping my shutter under sync and dealing with ambient in other ways.

 

[Gato Amarillo]

---
But would, say, a kit with two or three Godox AD600Pro monolights allow you to light adequately and to your taste, where you have to balance with outdoor daylight, using HSS instead of X-sync or a leaf-shutter lens?

"to your taste" makes it subjective and tricky to answer. Short form, no, I would rather have natural flash sync.

But since a leaf shutter or fast natural sync is not generally available for me I have to get by with HSS or stick to slower shutter speeds. Given a choice I'll stop down and stay within sync speed.

A kit like you describe would likely be enough for portraits or full-length of singles and couples, but might not be enough for group photos or automobiles. Probably not enough for architecture or sports action.

As to why leaf shutter lenses are not available, it probably comes down to high development and manufacturing cost vs. low demand.

Gato

 

[Ellis Vener]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses (which can sync at any shutter speed) in situations where you need to balance relatively bright ambient light with flash lighting on the main subject at large or moderate apertures?

In a thread in another forum (https://www.dpreview.com/forums/post/67209463), a user asked why Fuji doesn't offer leaf-shutter lenses for its GFX system. I suspect (and suggested) that the reason is that often HSS suffices.

I suspect the higher price point vs perceived need from surveying owners. is the real driver. I doubt Fuji takes into account lighting products sold by unrelated companies.

After all, today there are 600, 1000, even 1200 Ws monolights that feature HSS, and common lighting setups often involve more than one such flash. I realize that HSS reduces light output, and that modifiers like softboxes and umbrellas reduce it further.

But would, say, a kit with two or three Godox AD600Pro monolights allow you to light adequately and to your taste, where you have to balance with outdoor daylight, using HSS instead of X-sync or a leaf-shutter lens?

 

[bobby350z]

I have tried hot shoe flashes. Don't have power. I had the dual hot shoe mount thing. Never tried the 4 or more hot shoes like Joe McNally.

I have 2 XPLOR600s and I use 1200ws head to gang them. I have enough power to match the ambient but I can't beat the ambient. And I have to shoot full power which slows down you recycle time. Maybe I should try combination of HSS and ND filters. I haven't yet played with HyperSync as Godox Tx doe allow adjusting timing of trigger.

If I had a leaf shutter lens which went to 1/4000 or even 1/2000, it will mean AD400 would be plenty for my needs. Fuji can make a LS lens, charge for it. I will happily pay $1k more to make life easier.

Now I am not saying having LS will solve all the problems. I need to ensure my strobes have fast enough duration too.

 

[NAwlins Contrarian]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses (which can sync at any shutter speed) in situations where you need to balance relatively bright ambient light with flash lighting on the main subject at large or moderate apertures?

In a thread in another forum (https://www.dpreview.com/forums/post/67209463), a user asked why Fuji doesn't offer leaf-shutter lenses for its GFX system. I suspect (and suggested) that the reason is that often HSS suffices. After all, today there are 600, 1000, even 1200 Ws monolights that feature HSS, and common lighting setups often involve more than one such flash. I realize that HSS reduces light output, and that modifiers like softboxes and umbrellas reduce it further.

But would, say, a kit with two or three Godox AD600Pro monolights allow you to light adequately and to your taste, where you have to balance with outdoor daylight, using HSS instead of X-sync or a leaf-shutter lens?

First, thank you all for your responses and observations. They raise some interesting points, which I'll have to take a bit of time to digest.

My own experience and starting point is somewhat limited but I think somewhat illustrative: multiple times I've done things like shoot moderate-size group photos (e.g., a baseball team) in something approaching full sun, getting enough fill flash from a normal shoe-mount flash. Put the sun behind the group (to reduce squinting and harsh shadows), set the flash to fire at (manually-selected) full power, set the shutter speed to the X-sync speed, go as wide as I could on the aperture without blowing anything out, and shoot. I just pulled one of those up: ISO 100, 1/160 s, f/8, Sunpak 383 Super (GN 120 ft) at full power, sun high and over the subjects' left shoulders. Based on the focal length in the EXIF and the height of the field of view, the flash-to-subject distance must have been about 14 to 17 feet (basically two rows of subjects). The result was very satisfactory.

If a basic shoe-mount flash of 'normal' power can light a moderate-size group 14 ft away with backlighting maybe one stop down from full sun, then presumably even using high-speed sync and light modifiers, a pair of AD600 Pros* would suffice for the large majority of circumstances not requiring lighting huge subjects.

And that is why I suspect that leaf-shutter lenses are disappearing as an option, even from upper-end pro camera systems like Fuji GFX. But that is just my suspicion as a rank amateur who's never undertaken a location shoot for pay, or fired my White Lightnings outdoors.

*FWIW, Godox rates the AD600 Pro as having a GN of 87 m / 285 ft when used with the "high efficiency standard reflector". See https://godox.com/product-d/AD600Pro.html. I realize that many consider it a fool's errand to try to determine / rate studio flashed by Guide Number. Nevertheless, this facilitates some basic comparisons. Also, the relationship between Ws (i.e. J) and GN does not seem to be that hugely variable. Looking at a bunch of strobes and reflectors at the Godox and Paul Buff websites, their efficiency factors only range from 1.8 to 4.7, where efficiency factor = GN (in meters, at ISO 100) / SQRT(power in Ws). The Godox models are all in the 3.0 to 4.2 range, mostly specified with at least similar-sounding reflectors. The Paul Buff models are all around 1.9 with the "standard 7" reflector", 2.8 with the "high output 8.5" reflector", and 4.7 with the "11" long throw reflector".

 

[NAwlins Contrarian]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses (which can sync at any shutter speed) in situations where you need to balance relatively bright ambient light with flash lighting on the main subject at large or moderate apertures?

In a thread in another forum (https://www.dpreview.com/forums/post/67209463), a user asked why Fuji doesn't offer leaf-shutter lenses for its GFX system. I suspect (and suggested) that the reason is that often HSS suffices.

I suspect the higher price point vs perceived need from surveying owners. is the real driver. I doubt Fuji takes into account lighting products sold by unrelated companies.

I agree. But I suspect that surveying GFX owners doesn't indicate a big demand for leaf-shutter lenses because HSS has become available on some relatively powerful, reasonably-priced monolights, and is functional enough to cover the large majority of circumstances where formerly a leaf-shutter was needed.
My original post / question, maybe inartfully stated, was my attempt to learn: how often / to what degree do those who do a lot of outside-the-studio shoots find they need leaf-shutter lenses? Or is some combination of X-sync with a focal-plane shutter and/or HSS good enough for the large majority of circumstances?

Thanks!

 

[BillNi]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses

How about some theoretical?

At full power flashes convert all the energy stored in their capacitors to light. The difference with HSS is that the conversion is slowed so the flash lasts for about 1/100th of a second.

If it were possible to do HSS at 1/100th shutter speed the camera sensor would see all the converted light the same as a non-HSS flash. Actually there are likely some extra losses and probably more residual energy left in the capacitor so HSS will be down 1/3rd maybe 1/2 a stop.

Let's conveniently take the sunny 16 rule, 100 iso, 1/100, and F16 and for example the AD600Pro which has a guide number of 285 ft. Matching sunny 16 light with an AD600Pro requires a light to subject distance of about 18 ft which with HSS losses would be more like 16 ft.

So 16 ft light to subject distance is the base line for equalling sunny 16 ambient with an AD600Pro in HSS. Guide number/F18 will be about right for any flash/strobe.

 

[NAwlins Contrarian]

What is your practical experience regarding whether monolights or even shoe-mount flashes with high-speed sync (HSS) suffice in place of leaf-shutter lenses

How about some theoretical?

At full power flashes convert all the energy stored in their capacitors to light. The difference with HSS is that the conversion is slowed so the flash lasts for about 1/100th of a second.

That is not my understanding of the basic facts, but maybe I'm not understanding what you're saying.

The 'traditional' sync for a camera with a focal plane shutter is that the first shutter curtain fully opens to expose the sensor (or film), then the flash fires, then the second shutter curtain closes to mask the sensor (or film). Obviously this only works if the flash duration (actually, some sufficient middle-of-the-curve percent of it) is not longer than the time between when the first curtain opens and the second curtain closes.

With a traditional focal plane shutter, when the shutter speed gets faster than what's often called the X-sync speed, the second curtain starts moving to mask the sensor before the first curtain has fully opened to expose the sensor. In this circumstances, there is no time at which the entire sensor is capable of receiving exposure, and therefore no time at which a single flash could fire and expose the whole frame. Basically, as shutter speeds increase above the X-sync speed, the sensor is exposed by a narrower and narrower slit of opening between the first and second shutter curtains. Any time you fire the flash will only expose that part of the sensor that's behind the slit.

High speed sync works by having the flash emit a series of smaller flashes instead of a single, more powerful one. Basically, there are a series of flash pops as the open slit crosses the sensor, and each pop exposes that part of the sensor behind the slit.

But with only a limited amount of stored energy to make light, each flash pop in HSS mode has to be less than full-power. So the limit of the output is substantially less than it would be with X-sync operation and a single flash pop that can use all the stored power.

My previous main camera had an X-sync speed of 1/160 s; my current main camera has an X-sync speed of 1/250 s. Obviously any flash duration of 1/100 s or so is going to burn too long to use all its power to illuminate the sensor.

If it were possible to do HSS at 1/100th shutter speed

As explained above, it would be pointless to do HSS at 1/100 s shutter speed. Pretty much any semi-modern camera can X-sync faster than that.

the camera sensor would see all the converted light the same as a non-HSS flash. Actually there are likely some extra losses and probably more residual energy left in the capacitor so HSS will be down 1/3rd maybe 1/2 a stop.

Right, multiple smaller flash pops usually produce less light, AFAIK.

Let's conveniently take the sunny 16 rule, 100 iso, 1/100, and F16 and for example the AD600Pro which has a guide number of 285 ft. Matching sunny 16 light with an AD600Pro requires a light to subject distance of about 18 ft which with HSS losses would be more like 16 ft.

By most (all?) accounts HSS losses are substantially more than that. But for the sake of discussion:

Except of course at 1/100 s you'd just X-sync. HSS becomes an issue where instead of exposing the ambient / background 1/100 s at f/16, you want to use f/4 and therefore 1/1600 s. And when HSS is used at 1/1600 s, the AD600 Pro isn't going to put out an effective GN 285 ft. So in X-sync GN 285 ft / 16 = 18 ft maximum subject distance. Then you want to use f/4 instead of f/16, so you open up the lens, change the shutter speed to 1/1600 s, and put the strobe in the appropriate HSS mode. At that point, if the effective GN of each HSS flash pop is 72 ft, then the flash illumination of the subject is equal and the ambient illumination of the background etc. is equal, so all is good.

The problem is that, AFAIK, the effective GN of each flash pop in HSS mode isn't going to be 72 ft, it's going to be less.

And the question is: in what percent of circumstances will it be so much less that the AD600 Pro(s) can properly illuminate the subject when using a leaf-shutter to X-sync at 1/1600 s, but not when using a focal-plane shutter and HSS?

And then it's really a problem when the flash is needed with a smaller aperture: you want to shoot 1/6400 s and f/8. If you were at X-sync of say 1/200 s, then that AD600 Pro would (before modifier-related losses) give you up to 35 ft of subject distance; but if speeding up the shutter by five stops past X-sync reduces power proportionally or more, then you can't maintain the 35 ft, so then it's slower shutter speed or higher gain (ISO 800 or whatever).

So 16 ft light to subject distance is the base line for equalling sunny 16 ambient with an AD600Pro in HSS. Guide number/F18 will be about right for any flash/strobe.

I fail to see how this addresses the question.

 

[BillNi]

At full power flashes convert all the energy stored in their capacitors to light. The difference with HSS is that the conversion is slowed so the flash lasts for about 1/100th of a second.

That is not my understanding of the basic facts, but maybe I'm not understanding what you're saying.

Your understanding of the facts is wrong. HSS flash pulses are about 10ms long which is long enough to cover the transit time of the slowest focal plane shutters and allow a bit of timing slop.

About all the energy in the flash capacitors is converted to light in normal and HSS modes with HSS having some extra switching losses from the high frequency pulsing and probably leaving a bit more residual in the capacitor to avoid the light output tailing off towards the end too much. That's 1/3rd maybe 1/2 stop worth. People who talk about HSS losing 2 or 2.5 or 3 stops don't have a clue. HSS is down because it is used at shutter speeds where the sensor doesn't see all the produced light. How much down depends on the shutter speed used.

Where else do you think the stored energy goes in HSS mode?

Sunny 16 tells you at 100/th and F16 your sensor will receive X photons. Your flash guide number and F16 tells you what subject to flash distance you need to receive the same X photons from the flash. HSS produces the same number of photons (less 1/3rd or maybe 1/2 stop) over a 1/100th second which conveniently matches the sunny 16 1/100th.

The light intensity of an HSS pulse at guide number/F18 distance matches the intensity of sunny 16 sunlight. You were asking about balance and I thought this answers your question pretty well.

 

[NAwlins Contrarian]

At full power flashes convert all the energy stored in their capacitors to light. The difference with HSS is that the conversion is slowed so the flash lasts for about 1/100th of a second.

That is not my understanding of the basic facts, but maybe I'm not understanding what you're saying.

Your understanding of the facts is wrong. HSS flash pulses are about 10ms long which is long enough to cover the transit time of the slowest focal plane shutters and allow a bit of timing slop.

That is simply incorrect, according to Nikon and Fstoppers and everything I've ever read. Obviously if the pulse were about 10 ms long, that would be 1/100 s, which (as you say) would be longer than any of the shutter speeds at issue in HSS mode. But it's not a single, 10 ms pulse; it's a series of much shorter pulses.

Nikon says:

How It Works

In high speed sync mode the flash is not fired in one burst of light; it's emits a series of pulses, an incredibly rapid series that illuminates the scene as the camera's focal plane shutter moves across the sensor. This strobing action takes an enormous amount of flash power, and the flash essentially divides up the amount of light into segments as the shutter travels. The faster the shutter speed, the less flash power is available. Often the reduction in power does not noticeably affect the image, but when it does, photographers often compensate by either moving closer to their subjects or using more than one Speedlight.

Source: https://www.nikonusa.com/en/learn-a...e-to-add-a-pro-touch-to-your-photographs.html (bold in original; italics added)

Likewise, Fstoppers says:

A flash in HSS acts much like a constant light (similar to controlling ambient light: the faster your shutter speed the darker the ambient light gets) and as such you will start to lose flash power at higher shutter speeds. It basically turns your flash into a high-speed strobe light. It pulses light extremely fast and consistent while your shutter curtains are passing in front of your sensor. This pulsing is not noticeable to the human eye.

Source: https://fstoppers.com/lighting/demystifying-high-speed-sync-68527

Let me be clear: I'm not asking about how HSS works. I know how HSS works. I'm asking people who use HSS with monolights and/or shoe-mount flashes how often, if ever, they run into the problem of not having enough light output when in HSS mode, where they would have enough power if they could X-sync.

 

[RL Photography]

Where else do you think the stored energy goes in HSS mode?

It hits the shutter curtain.

 

[BillNi]

nding of the facts is wrong. HSS flash pulses are about 10ms long which is long enough to cover the transit time of the slowest focal plane shutters and allow a bit of timing slop.

That is simply incorrect, according to Nikon and Fstoppers and everything I've ever read. Obviously if the pulse were about 10 ms long, that would be 1/100 s, which (as you say) would be longer than any of the shutter speeds at issue in HSS mode. But it's not a single, 10 ms pulse; it's a series of much shorter pulses.

As I said in the first post the conversion of energy in the flash capacitor to light is slowed in HSS mode. It is usually slowed by rapidly switching on and off the voltage applied to the tube. Rapidly being about 25,000 times a second. The on/off duty cycle is used to control flash power and probably to compensate as the capacitor voltage falls during the flash. Elinchrom have HS strobe heads which slow the conversion by having higher resistance tubes no rapid pulsing involved.

I didn't mention the mechanism by which the conversion is slowed because it is irrelevant. Your eyes and the camera do not see the rapid pulsing they see a single pulse.

The important thing is the single pulse lasts for 1/100th of a second. Knowing how much energy there is to convert during that 1/100th tells us how bright the produced light is and allows us to compare it with other light sources.

 

[BillNi]

Where else do you think the stored energy goes in HSS mode?

It hits the shutter curtain.

........after it has been converted to light.

 

[RL Photography]

nding of the facts is wrong. HSS flash pulses are about 10ms long which is long enough to cover the transit time of the slowest focal plane shutters and allow a bit of timing slop.

That is simply incorrect, according to Nikon and Fstoppers and everything I've ever read. Obviously if the pulse were about 10 ms long, that would be 1/100 s, which (as you say) would be longer than any of the shutter speeds at issue in HSS mode. But it's not a single, 10 ms pulse; it's a series of much shorter pulses.

As I said in the first post the conversion of energy in the flash capacitor to light is slowed in HSS mode. It is usually slowed by rapidly switching on and off the voltage applied to the tube. Rapidly being about 25,000 times a second. The on/off duty cycle is used to control flash power and probably to compensate as the capacitor voltage falls during the flash. Elinchrom have HS strobe heads which slow the conversion by having higher resistance tubes no rapid pulsing involved.

I didn't mention the mechanism by which the conversion is slowed because it is irrelevant. Your eyes and the camera do not see the rapid pulsing they see a single pulse.

The important thing is the single pulse lasts for 1/100th of a second. Knowing how much energy there is to convert during that 1/100th tells us how bright the produced light is and allows us to compare it with other light sources.

You are confusing High Speed Sync with HyperSync, which Elinchrom refers to as Hi-Sync. They are different things.

 

[BillNi]

You are confusing High Speed Sync with HyperSync, which Elinchrom refers to as Hi-Sync. They are different things.

Other than name and mechanism used to increase the flash pulse duration in what way are they different?

 

[Ellis Vener]

Like a way to demonstrate the difference in exposure between a flash in standard and HSS mode, because we changed the shutter speed of a camera with a focal plane shutter from its X-sync speed to 1/3rd of a stop shorter (I.e., from 1/200th to 1/250th)…

if only we had the tools available to stage a demonstration and share the methodology so anyone can repeat it…

If only…

 

[NAwlins Contrarian]

To try to be clear, I was not and am not asking about how HSS works. That's not even relevant to what prompted me to start the topic.

I'm asking people who actually use HSS with monolights and/or shoe-mount flashes how often, if ever, they run into the problem of not having enough light output when in HSS mode, where they would have enough light output if they could X-sync. Obviously if you run out of light output in HSS mode, but you would have enough light output if you could X-sync, then a leaf shutter would benefit you--which was my original point of interest.

Thanks!

 

[BillNi]

Like a way to demonstrate the difference in exposure between a flash in standard and HSS mode, because we changed the shutter speed of a camera with a focal plane shutter from its X-sync speed to 1/3rd of a stop shorter (I.e., from 1/200th to 1/250th)…

if only we had the tools available to stage a demonstration and share the methodology so anyone can repeat it…

If only…

Serious or ironic?

I just repeated a test I did a while ago. Camera on tripod, darkened room, Godox V860II in the hot shoe bounced from the ceiling. Shutter below sync speed, flash non-HSS set to full power, and F8 gave a reasonable exposure.

Then switched to HSS and 1/400th shutter. I predict it will need 2 1/3s stops more exposure to produce the same image brightness. 2 stops because the sensor only sees 1/4 of the 1/100th second HSS pulse and 1/3 for HSS losses. As predicted F3.5 gave an image with the same brightness.