does High Speed Sync diminish the life of a speedlight

Discussion in 'Lighting Equipment' started by bob_estremera, May 15, 2015.

  1. I'm looking to do an outdoor portrait project with the new Godox/Neewer 850 speedlights using their HSS function with my Canon 60D and/or EOS M.
    I need to kill lots of ambient light with high shutter speeds.
    It seems that the continuous pulsing used by the flash to achieve HSS would prematurely shorten the life of the speedlight compared to just regular single pops.
    Does anybody have any input on this?
    Thanks,
     
  2. Don't know the answer but another way of looking
    at it is, what is more important to you: getting the
    shots you want or making the gear last as long as
    possible?
     
  3. Thanks Brian,
    It's a budgeting issue. If I'm going to wear out the units faster than usual, I want to know that beforehand so I can purchase accordingly.
     
  4. I have no idea but the flash will turn off when it overheats. If that happens often it's a sign you're putting too much stress on it.
    BTW, I have never heard that HSS can shorten the flash's life.
     
  5. Hi Bob,
    HSS is actually not the full power flash but longer bursts. It will damage the flash in the long run, but how often are you going to be using the HSS function? Go for it.
     
  6. I think it may shorten the life of the flash tube, but not the flash itself. Can the flash tube be replaced on the flash you are looking at?
    I know that they can be replaced on Canon and Nikon speedlights and are also available for those that can do it themselves at low cost, $10 or so.
     
  7. That's a great question Pete. I'll have to Google around and see if the tubes are replaceable.The speedlight itself is pretty cheap, around $107 US so it's not the biggest calamity if I have to replace it sooner than I'd like but replacing tubes would be great.
    And Starvy, for this project, I would be using HSS exclusively on any given day.
    Thanks,
     
  8. How close will the lights be to the subject? Unless you are working with the speedlights close to the subject you might find
    yourself needing multiple speedlights to overcome "lots of ambient light" if by that you mean daylight.
     
  9. The quick succession of
    flashes produced in FP flash
    mode probably puts no more
    strain on the tube or
    circuitry than the multiple
    pre-flashes used for TTL
    exposure control and slaving
    other flashes.

    And if you're worried you can
    use almost any old flash for
    FP exposure. Just as long as
    you have an FP/HSS compatible
    flash fitted to the camera's
    hotshoe. Search for FP or HSS
    threads in this forum to see
    how it's done.
     
  10. BTW. Using FP synch and a
    high shutter speed gains you
    nothing in terms of ambient
    to flash ratio. The flash
    either has enough power to
    compete with the ambient
    light, or it doesn't. Using
    FP synch won't increase the
    power of your flash.
     
  11. "BTW. Using FP synch and a high shutter speed gains you nothing in terms of ambient to flash ratio. The flash either has
    enough power to compete with the ambient light, or it doesn't. Using FP synch won't increase the power of your flash."

    No it won't . But if it is either powerful enough in FP /HSS /Hypersync mode and if it is close enough to the subject if
    definitely can overpower daylight.
     
  12. I don't know, but would doubt HSS has much effect on the flash tube life.
    It does have to fire for the full shutter speed duration instead of a much shorter brief pulse, but it operates at most at about 20% power level to be able to do that.
     
  13. I'm going to be very close. Close enough to hand-hold the speedlight with my subject only a few fee away. I would be shooting at very low power levels (if shooting regular, without the HSS). I've seen the effect accomplished with leaf shutter cameras where a shutter speed of 1/1000 or so is used to drop the ambient around three stops, maybe more, and the flash is used just for the subject. And I won't be trying to kill bright sunlight, more like open shade.
     
  14. I'm speaking Nikon, and assuming most is the same.
    I think you will be towards higher power (higher for HSS, which is low). A few feet is fairly far for HSS. :) Fill flash only needs about 1/4 the power of a main flash (to be one stop down), and in bright sun, HSS has about ten feet range (as fill). Joe McNally has promoted HSS for fill in sunlight, but he uses about four larger flashes ganged in tandem. :)
    HSS is continuous light, like sunlight is continuous light. HSS acts more like a desk lamp, it does not act like flash. The thing to know about continuous is that Equivalent Exposure works again, both for ambient light and for HSS flash. The manual probably gives Guide Number for 1/500 second HSS, but again, the thing to know is that (for HSS) the same GN is good for any equivalent exposure. High shutter speed greatly reduces both ambient and HSS exposure, but for both, we open aperture to compensate (equivalent exposures).
    But I doubt long life of flashtube will be a concern.
     
  15. "I've seen the effect accomplished with leaf shutter cameras where a shutter speed of 1/1000 or so is used to drop the ambient around three stops, maybe more, and the flash is used just for the subject."​
    The point is, unless you need a high shutter speed to get a wide aperture, that the ambient light isn't actually "dropped" by using FP synch. Say your flash exposure at normal X-synch (~1/250th) needs an aperture of f/11, and the open shade needs f/5.6. This puts your flash two stops above the ambient. Now you increase your shutter speed to 1/500th and go into the realm of FP synch. You'll now find that the flash needs an aperture of f/8, because it outputs the same total amount of light, and the ambient needs f/4 - same two stop difference. Increasing the shutter speed to 1/1000th still gets you nowhere, because now the flash needs an aperture of f/5.6 and the ambient needs f/2.8. Hummm, that's still two stops difference!
    It doesn't matter how you juggle the ratio between flash and ambient, using FP synch won't change it. The limit will still be how powerful your flash is and how far distant it is from the subject.
     
  16. I hope I'm allowed to link to a post on another webite.
    Maybe I'm just confused but look at this photo: http://www.fredmiranda.com/forum/topic/1209248
    From what I THOUGHT I understood, the high shutter speed allowed the overall scene to be underexposed while the flash can light the subject as desired. That is why I thought there were two separate exposures to be made - one for the overall scene (underexposed to the desired degree with a higher shutter speed) and the other by adjusting the power of the speedlight. I see these examples often when photogs describe how the X100's allow this because they can sync at very high speeds. So for instance, I have my subject in the open shade. But I want to lower the overall light values of the scene. I want to leave my aperture around f2.8 or f4 for depth of field reasons. If shorten the shutter duration to, say 1/1000 of a second, I get a nice dark overall scene, underexposed from a normal exposure. Now I light my subject with the flash adjusting the power until I get the value on the subject that is 'normal', exposed correctly. Given my example, isn't that the correct evaluation of the process to get the look I want?
     
  17. I think you're generally correct, but are overlooking that the Fuji 100s is a big difference. It's special shutter can sync regular flash at (I think) 1/4000 second. The DSLR cannot.

    So that Fuji is not doing HSS at all, it is using regular flash mode. DSLR cannot.

    Regular speedlight flash - amazingly fast duration at lower power levels (called speedlights), and so flash exposure is not affected by shutter speed (flash is faster than the shutter). And full power is available.

    HSS flash - runs about 20% power anyway, and is continuous light (like the sun), so fast shutter speeds simply decimate its exposure (like the sun). You can open the aperture (equivalent exposure), but that helps the ambient just as much.

    You want to use fast shutter to reduce the ambient, but fast shutter also reduces the continuous HSS flash BY THE SAME AMOUNT. No gain for your purpose, unless you can turn the HSS power up (get a few HSS flashes ganged together (8 equal flashes is 3 stops more). HSS is NOT at all like regular flash. Continuous light is continuous light.

    The plan could work with regular flash (except for fastest shutter speed) because shutter speed does NOT reduce the regular flash exposure - because the speedlight flash is typically faster than the shutter.
     
  18. Good explanation Wayne.
    I think you're generally correct, but are overlooking that the Fuji 100s is a big difference. It's special shutter can sync regular flash at (I think) 1/4000 second. The DSLR cannot.​
    That "special shutter" is a Leaf Shutter. It can sync up to 1/4000 using the built-in flash or an on-camera speed-light.

    http://www.fujix-forum.com/index.php/topic/8857-flash-sync-speed-for-x-100-s/
    It doesn't matter how you juggle the ratio between flash and ambient, using FP synch won't change it. The limit will still be how powerful your flash is and how far distant it is from the subject.​
    There in lies the rub. Generally, built-ins and on-camera speed lights are pretty weak for out-door work (depending on the ambient conditions and distance to subject).

    When you move to more powerful lighting solutions, the flash duration at various power levels has to be taken into consideration … and if you then use a radio trigger, the max sync speed of the trigger device has to be understood … typically, many are 1/500 for leaf-shutter cameras, or in the case of Profoto AIR 1/1000 in speed mode.
    DSLR cannot.​
    That may be changing … TTL off-camera strobes with HSS are the next wave … the difference being that the HSS output from a 500 W/s strobe is a lot more than HSS with a 70 W/s speed-light.

    - Marc
     
  19. Here is a post from another blog about using the Godox 850 speedlight that has caught my eye because of its HSS capabilities - http://michaelmowbray.com/2014/05/09/godoxneewer-850-the-perfect-studio-speedlight/
    In the photo of the young woman he's using a fill light that I would do without. I want a more dramatic lighting and I'll take the shadows.
    The photog was able to sync at 1/1,600 of a sec. with the flash at 1/2 power.
    Anyway, this was the flash and style of street portrait that made me raise the question in the first place.
    And again, distance of the flash to the subject is going to be VERY close.
     
  20. 1/1600 at 1/2 power, but at f/1.8, and ISO or distance was not mentioned. So we don't know a lot.

    Not sure what you are expecting, but I think the flash is special only because of the battery... its type and capacity and recycle speed. Sounds good, but that in itself will not affect HSS exposure.
    Guide Number 58 (meters) is surely at maximum zoom, and so it is a large speedlight (like many others are large... Nikon SB-800 is same GN, they just don't advertise it only at the 105mm zoom maximum value). And the price is right, but these are regular flash GN, not about HSS.
    We need a user manual with a GN chart, but ..
    Other HSS units typically (roughly) have a HSS GN about 1/3 of regular mode GN, specified at 1/500 second.
    For HSS, any equivalent exposure would have the same GN.
    Zoom 24mm GN is generally about half of 105mm zoom GN.
    With these very vague generalizations, 58/2 = GN 29/95 (meters/feet) at 24mm.
    1/3 of that for HSS is about GN 10/32 (meters/feet).
    So GN 32 at 6 feet is f/5.3 at 1/500 second, ISO 100, 24mm, direct flash.
    Or one equivalent exposure is f/2.6 at 1/2000 second (two stops is fstop / 2, shutter denominator x 4)
    Would not bet on my precision, but possibly halfway ballpark, and it sounds doable if close.
    But aperture, shutter speed, or ISO will all affect ambient the same as HSS flash. In camera P mode in sunlight, we can spin the equivalent combinations up or down without affecting either ambient or HSS flash exposure.
    This is because both are continuous light. As far as the shutter is concerned, the HSS light was there when it opened, and was there when it closed. To the shutter, it is same as daylight was always there...continuous. HSS reacts very differently than regular speedlight mode.
     
  21. Even using a leaf shutter doesn't buy you much extra flash-to-ambient ratio. Below is a graph of light output over time for a typical hotshoe style flash (i.e. speedlite or speedlight). You'll see that it takes a short but finite time for the flash to reach its maximum output, after which it decays relatively slowly.
    A leaf shutter at 1/1000th of a second will capture around 50% of the useful light output, so you're already down a stop on the exposure required at 1/250th second (4 ms). At 1/4000th of a second the flash hardly has time to reach its peak output, and even if it did, the shutter would only allow a small slice of the useable light output through.
    All-in-all, the advantages of using flash with a high shutter speed are grossly overrated and overstated.
    BTW. In those shots by Michael Mobray, he's using FP synch to enable a wide aperture to be used, and not to overpower the daylight. If you notice, the daylight is sunset/twilight in two examples and dull/overcast in the other. None of them would look much different - apart from the depth-of-field - if normal X-synch and a smaller aperture had been used.
    I also don't see any reason why the (frankly ugly) lighting of the woman and dog shot couldn't have been duplicated at a slower shutter speed. An ND filter would knock the daylight exposure down just as effectively as using a high shutter speed.
    00dIa9-556835784.jpg
     
  22. "I also don't see any reason why the (frankly ugly) lighting of the woman and dog shot couldn't have been duplicated at a
    slower shutter speed. An ND filter would knock the daylight exposure down just as effectively as using a high shutter
    speed."

    That's why people have opinions: so they can find things to disagree about. (-;

    For fashion light I think it's perfectly fine, if you like that raw look. The background however is crap. Why is it crap (imo of course)? Because it's distracting and doesn't a single thing to the photograph. It's just visual garbage.
     
  23. I also don't see any reason why the (frankly ugly) lighting of the woman and dog shot couldn't have been duplicated at a slower shutter speed. An ND filter would knock the daylight exposure down just as effectively as using a high shutter speed.​
    Regardless of your opinion of the shot, wouldn't a ND filter also effect the flash exposure requiring more light on the subject? (which is okay IF you have more light).
    Even using a leaf shutter doesn't buy you much extra flash-to-ambient ratio.​
    That depends on what leaf-shutter camera you are using. Focal Plane Medium Format cameras are typically 1/125 sync … where a leaf shutter MF camera can be 1/500 or 1/1000 sync (and in one case 1/1600).

    Despite charts to the contrary, practically speaking that can be the difference between a white blown sky or blue sky and clouds.

    In the example below, where I knew I would be force into a difficult lighting situation before hand, I brought a 600 W/s pack set to full power with a magnum modifier, and combined it with an on-camera speed-light set to max zoom and manual full power aimed straight at the distant back-lit subjects. In reality, I needed at least 1200 W/s, but made due. Back-up shots with a focal plane camera set to 1/200 max sync resulted in a blown sky except in the far left side. This was printed 12" X 18" in a wedding album, and each face was clear and identifiable.

    IMO, and direct experience, Leaf Shutters work better than you "grossly" dismiss and "understate" … they have saved me in many cases where the time of day and place the client wants to shoot is out of my control.
    00dId1-556839884.jpg
     
  24. In this case, I used on-camera HSS because I was close enough to fill the back-lit subject while knocking down the background 2 stops and avoiding blown highlight areas from a hot sun high camera left.
    00dId2-556840084.jpg
     
  25. One other aspect of using a Leaf Shutter camera is that IF there is a trail off of lighting as shown in the chart above, the effect is one of vignetting because of the way a leaf-shutter works.
    Vignetting of that uniform type is often either pleasant looking pictorially, or exceedingly easy to adjust in post using well developed lens vignetting tools found in virtually every photo editing program available.
    In this case there was some minor Leaf-Shutter vignetting @ 1/1000, which I then enhanced even more …
    00dIdF-556840384.jpg
     
  26. Very nice shots Marc. Your wedding examples are the exactly what I want I hope to achieve with the HSS sync function. And I don't expect to have to knock down that intense outdoor sun, rather open shade for an even darker background. Can I ask which leaf shutter camera or lens combo you used?
     
  27. A quick, down and dirty test of the Canon HSS E-TTL metering from this morning. The camera used is a Canon EOS 7D mark II and the flash is a Phottix Mitros. Seethe caption for the rest f the information. The subject (me) was standing in the shade of a large tree.
    00dIej-556843884.jpg
     
  28. You handsome devil Ellis.
    Your test illustrates what had been my assumption, the subject illumination is staying more or less the same (the last lighting on you seems to be a bit darker though) while the overall scene is darkening with increasing shutter speeds. And my plan is to have the light even closer.
    Thanks Ellis.
     
  29. I believe the fall off in brightness has two causes:
    1) in HSS mode the speed light is producing a stream of discrete low power pulses of light (not the smooth curve RJ
    published earlier . That curve represents the light production on non-IGBT flashes while all HSS/FP capable flashes
    whether it's a monolight like the Profoto B1 and B2 or the Phottix Indra500 and Indra320, and all HSS capable hot shoe
    mount flashes use IGBT gates to control output duration) and as you go up there he shutter speed scale the pulses
    increase in frequency and reduce the energy of each pulse.

    2) Even though I was shaded from direct illumination by the sun, the sky above me was contributing some light, and
    obviously shortening the shutterspeed reduced that ambient light as well.

    I suspect the reduced level of exposure on me is about 2/3rds due to how HSS works (1) and 1/3 reason#2
     
  30. Further thoughts. HSS/FP flash acts like a virtual constant light - as the length of the exposure is decreased in full stop
    ncrements , in my example going from 1/200 to 1/400 to 1/800 - the exposure will decreased by half as you'd expect
    with a true constant light.
    However, when the flash and camera are in FP (Nikon) or HSS (Canon) mode the camera directs the flash to put out
    more light to compensate, but of course how much light it puts out is limited by the maximum capacity of the flash.

    If you are not illuminating a wide area you can increase the efficiency of the flash by zooming its internal reflector to a
    narrower beam angle.
     
  31. TTL (HSS or speedlight mode) will meter and adapt to changes in settings (put out more power) to keep metered exposure constant, but HSS can be manual flash too (which won't). But being continuous, the big difference of HSS from speedlights is that TTL or manual, "equivalent exposures" are equivalent, for both continuous ambient or continuous HSS flash. This is what easily allows HSS to do like 1/6400 second at f/2.8 in sunlight. Any equivalent is equivalent.
     
  32. Hi Bob, to answer your question … I use a Leica S2, and now S(006), with a range of CS (Central Shutter) lenses. I also have used Hasselblad HC & HCD lenses on the S camera using Leica's fully functional H to S adapter. Commercial work primarily paid for such expensive gear, so I was able to also use it for portraits and weddings. The Leica S camera syncs up to 1/1000 with CS lenses, and 1/800 with Hasselblad H lenses.
    I use Profoto AIR equipped lighting which allows wireless sync speeds to 1/1000 with the S leaf-shutter lenses. Currently that includes B1s, B2, and my older Acute B2-600 AIR Lithium. It doesn't provide Off-Camera TTL for my Leica or Sony cameras. Only for Canon and Nikon.
    Here's an example of placing a Bat-Mitzvah subject in shade with a bright late spring morning sun background. I wanted a fresh faced, shadowless look, with a pastel out-of-focus background.
    Leica S2 @ ISO 320 CS-120/2.5 @ f/3.4 (Similar to a 100/2 in 35mm) … using 1/350 shutter to just record the background (but not to deep of an exposure to keep it light and airy). The lighting was set just camera left using a 27" deep octabox with dual diffusers. As the eye spectral highlights show, even the 27" box was a smallish light source.
    In retrospect, I probably should have used 1/500 to decrease the background exposure a tad then placed a bit more light on the subject … because when the subject is in shade, skin tone can go a bit bluish (see her shoulders) … or, IF shooting where there is a lot of foliage, the subject shadows tend to go greenish (which isn't easy to fix in PS).
    - Marc
     
  33. OOPS!
    Here's the above mentioned shot : -)
    00dIkN-556853984.jpg
     
  34. To be fair Ellis, you also needed to include a 1/200th shot with the same settings you used for the FP mode shot(s) - i.e. camera minus exposure and no flash compensation. That's why the background in your "HSS" shots is darker, not much to do with the shutter speed at all.
    It's still all down to having sufficient flash power to overcome the ambient lighting. Using an ND filter or lowering the ISO will certainly lower both the daylight and flash exposure, but as long as you can increase the flash exposure to compensate, the method of changing the exposure doesn't matter. The same applies equally to raising the shutter speed with an FP/HSS mode flash.
    A leaf shutter does indeed show better use of electronic flash at speeds between 1/500th and 1/1000th, but the efficiency increase amounts to a stop at most. That wasn't being argued. But comparing a 600 W-s strobe with a comparatively feeble 75 W-s speedlight (or lite) is totally irrelevant to the discussion of how effective FP/HSS mode is on a DSLR versus X-synch. Nobody is going to argue with the fact that more flash joules can compete with daylight better than a lower amount of energy.
    BTW, a leaf shutter acts in the same way as a fast opening aperture iris, so it won't produce vignetting, even if the exposure changes during the shutter time. There's no "IF" about the electronic flash discharge curve. It's been measured and recorded on numerous occasions, and most decent strobe manufacturers will supply a graph, or at least give the t-0.5 or t-0.1 times. A few milliseconds is typical.
     
  35. "To be fair Ellis, you also needed to include a 1/200th shot with the same settings you used for the FP mode shot(s) - i.e.
    camera minus exposure and no flash compensation. That's why the background in your "HSS" shots is darker, not much
    to do with the shutter speed at all."

    Nonsense. The effect of biasing the exposure serves only one purpose: changing the shutterspeed. That changes the
    ratio of the ambient light to flash.
     
  36. "Nonsense. The effect of biasing the exposure serves only one purpose: changing the shutterspeed. That changes the ratio of the ambient light to flash."
    But there is more to it than that. Are you evaluating TTL or HSS?
    Your words are terse, and it's difficult to be sure I grasp all the implied meaning, but the words that describe the situation are not said...

    I think you overlook that changing shutter speed affects both HSS and ambient in the same degree. I think you may try to show it does not, but that would be wrong. There is no difference. Because both are continuous. To the shutter, HSS is pretty much like a desk lamp. But TTL is the complication that desk lamps don't have.
    I think you are saying you are changing Exposure Compensation, but Not Flash Compensation. FWIW, on Canons, Exposure Comp only affects ambient (but on Nikons, it affects both ambient and flash, but latest models have a choice switch now).
    And the cameras have two metering systems, for ambient and for TTL flash. Ambient is metered to establish missing factors of shutter, aperture and Auto ISO, and flash preflash is metered to establish flash power level for the situation it finds itself in.

    So EC of -1 or -2 EV instructed to knock the ambient metering goal down, and it did it. Ambient got darker.
    But the TTL flash metering goal was Not changed (no compensation), so it continued as before, maintaining same goal as before. And it did that too. However now the shutter speed was faster (set by ambient EC), so it had to use more power to do the same exposure goal as before, because HSS is affected by shutter speed exactly like continuous ambient. Bless its little heart, it tries to do what is requested.
    HSS varies with shutter speed too, but your TTL is what is telling the flash to compensate itself, to not vary. You are testing TTL, not HSS. TTL is why the regular flash came out same exposure as the much weaker HSS, and also why the shutter speed did not change HSS either. But due to faster shutter speed, HSS has to work a lot harder to do what TTL asks of it.
    TTL maintaining its goals is a confusion factor for inspecting how HSS works. You could try same thing at maybe 20 feet, and get very different results (because HSS could not comply with the greater TTL requests). Manual flash mode makes it much more obvious to see, no confusion about TTL running the show. But the only answer is about continuous and about equivalent exposures, and that both ambient and HSS are affected in the same degree by shutter speed. Twice as fast is half the light.
     
  37. What Canon has to say about HSS mode. (This is from Canon's guide to the 580EX II):
    "High-Speed Sync
    When this option is selected the flash will flash stroboscopically, in sync with the shutter as it cross the focal plane.
    Although this allows the 580EX II to synchronize with shutter speeds higher than 1/200-second it also reduces light output
    as shutter speeds move progressively past the standard maximum sync speed."

    And that description listed as as being an E-TTL mode. HSS is also mentioned under manual operation but only to refer
    to the above description in the E-TTL section.

    The link to the above is http://learn.usa.canon.com/app/pdfs/quickguides/CDLC_580EXII_QuickGuide.pdf

    At http://pixsylated.com/blog/simple-truths-about-high-speed-sync-2/ Syl Arena, who is to the Canon Speedlite system
    what David Hobby or Joe McNally are to The Nikon Speedlight system, there is this

    "Taming The Sun With High-Speed Sync
    Another benefit of high-speed sync is that you can overpower the sun with a small speedlite or two. In the photo above,
    you’ll note that the sky and background (basically, everything lit by the sun) is underexposed. Why? Two reasons. I
    wanted to make my subject the dominant element (aka: the brightest part of the picture). I also wanted to reduce the
    competition between the geometry of her arms and the geometry of the lattice. How? I set my overall exposure at -2 EV
    and my flash exposure at +2 EV. That’s about all the thought I put into it. I let the digital gnomes in my camera do the
    calculations.

    In the following shot, you’ll see the underexposed daylight at left and the effect of the high-speed sync at right.

    Setting Up High-Speed Sync
    On Canon 580-series or 430-series speedlites, your flash must be set to ETTL mode. Then push the H-button until you
    see the H-icon on the screen. You are now in high-speed sync mode. Frankly, I keep high-speed sync on all the time. I
    shoot in aperture-priority (AV) mode 99% of the time – meaning that I’m almost always more concerned about controlling
    depth-of-field than I am about stopping motion. There’s no harm in leaving high-speed sync on. When I dial to an aperture
    that enables a shutter speed of 1/200 or slower, the camera automatically operates the flash at normal-sync mode –
    meaning that the full power of my speedlite is available."

    So it's impossible with the Canon system (at least, possibly Nikon as well) it is impossible to divorce HSS from E-TTL
    metering, hence my need to dial in exposure compensation to get shorter than standard sync speed if you want to keep
    aperture and ISO constant while working in Aperture Priority mode.
     
  38. "think you overlook that changing shutter speed affects both HSS and ambient in the same degree. I think you may try to
    show it does not, but that would be wrong. There is no difference. Because both are continuous. To the shutter, HSS is
    pretty much like a desk lamp."

    I don't think I am overlooking that at all. But with the Canon system HSS is part of the E-TTL system. THE E-TTL
    computer is controlling how much light the Speedlite is emitting. At a certain point - fairly quickly reached with a Hotshoe
    mount flash it reaches the limit of how much light it can put out in a given period of time. The thinner the slice of time the
    more quickly that maximum per flash is reached.


    Now back to the original question. Does HSS work burn out a flash tube more quickly? That is a trickier question. If you
    are constantly and quickly shooting with the flash system putting out what amounts to a full discharge of the capacitors
    heat and ionized air will build up inside the flash head which is sealed. In the case of the Canon 580 EXII THE design
    puts the mylarized reflector very close to the flash tube's cathodes and a certain point it becomes as easy for the current
    to discharge across the gap between cathode and reflector than through the metallic gas inside the flashtube, and that's
    what kills the flash. (Source http://lpadesign.com/580EXII.pdf)

    This issue has only been reported with the 580 EX II but not with other Canon Speedlites or Nikon Speedlights. With the
    wild and widening world of non-OEM "Smart" hotshot mount flashes your guess is as good as mine.
     
  39. I am thinking that must be a wrong conclusion. I am Nikon, and don't know Canon at all, but your link to the 580 Canon QuickGuide (first page, bottom of left column) says HSS is "only in TTL or Manual mode". I don't know about your other linked article, but Nikon HSS certainly works in TTL or Manual. Why wouldn't it? Manual is just a flash level. But I really don't know what Canon might do.
    The easiest thing is to simply just try it. My bet is it works fine in Manual. Because a flash is just a flash, and TTL or Manual are both just a power level setting, regardless of who set it how. Then in Manual mode, change shutter speed, aperture, and ISO in any Equivalent Exposure way, and you will still have the SAME exposure, from sunlight, and from HSS. You will in TTL too, Equivalent or not, but that's TTL, and not about HSS.

    Bright Sun Equivalents
    Sunny 16, ISO 200
    1/400 second at f/11
    1/800 second at f/8
    1/1600 second at f/5.6
    1/3200 second at f/4
    1/6400 second at f/2.8
    1/200 second at f/16 should be in this list, but was omitted because 1/200 second would not enable FP flash mode (very different modes).
    When changing things in TTL mode, the TTL metering will keep it the same, by metering for different power levels for the same goal, but again, that is not about HSS. But HSS is simply one steady continuous light, so of course Equivalent Exposures work.
    Equivalence is what allows f/2.8 to be used in sunshine. Works for HSS flash too.
    Other than short range, HSS makes fill flash in sunlight easy (and allows f/2.8 if we crave it). Just set the Manual flash level or TTL compensation for ratio (if Balanced flash mode has not already done it), and then any equivalent exposure that exposes the ambient also exposes the flash the same as expected. Just like any two continuous light sources.

    HSS is really one single flash, a long one from many repeating small triggers to keep it alive (flash tube ionized) for shutter duration (like even a few seconds). It is Continuous light for the duration of the shutter, with maximum of about 20% power to be able to stay alive. It is NOT many small flashes, it's one flash with many triggers. The trigger repeat rate is in the order of 70,000 Hz, last I heard. That is rather continuous, and they all run together with hardly a ripple. :) The eye will not detect any problem. :)
    Experiment a bit, using it a little will make it come clear. No one explains it like it should be explained. It is Continuous light for the shutter duration, so it acts like continuous light, and all that implies (primarily equivalent exposures). As far as the shutter can see and know or care, the flash might have been on for hours or days. In the early days, all we heard about it was that faster shutter speed drastically reduced its light, like that was a terrible thing, unheard of in flashes. :) We heard some stupid theories, but which of course is exactly how sunlight or incandescent light works too. We ought to be used to it. :) Because it is simple Continuous light, and it acts like Continuous light (one characteristic is no sync concerns). I have a HSS page at http://www.scantips.com/lights/flashbasics2b.html if interested.
    So with no sync requirement for continuous light, then we merely open aperture to compensate shutter speed, which is called Equivalent Exposure (same as for sunshine). Speaking Nikon, but the flash manual quotes one Guide Number for HSS, probably at 1/500 second (which is Manual flash of course). Nikon never mentions this, but the point that we should know is that the same Guide number then works for any Equivalent Exposure (any shutter speed at corresponding aperture, same as like sunshine). The big deal is that Continuous light offers Equivalent Exposures (and no sync). Faster shutter speeds simply compensate by opening the aperture, same as we learned back on Day One. Just try it, it becomes very clear then.
    Try running shutter speed or aperture or ISO up and down, and TTL handles it. It will affect Manual HSS flash, UNLESS they are Equivalent Exposure changes, in which case, then no exposure change in HSS.
     
  40. Per your second article, the camera does have to talk to the flash, so HSS mode cannot be set if on a manual radio or optical trigger, but manual flash works fine remotely via the Nikon Commander, and of course, if on the hot shoe.
     
  41. "THE E-TTL computer is controlling how much light the Speedlite is emitting."​
    Exactly the point Ellis. You can't tell that the power of the flash is being increased when you go into HSS, because the speedlite does it automatically. To test the limit of HSS you'd have to put the subject at the maximum guide-number distance - then you'd see how much "better" HSS is than standard X-synch.
    The clues are all in the quotes from Canon that you've given in your own post Ellis. The flash works stroboscopically in HSS mode, i.e. it outputs a series of short pulses of light. That means that it cannot give the same peak quantity of light as it can in X-synch mode, because the capacitor only stores a fixed amount of energy and the recharging circuit can't supply it with power fast enough to significantly top up that energy during the HSS discharge time. The net result is that HSS is actually weaker in output than standard X-synch mode.
    What I was suggesting as a fair test, was to set the camera manually to 1/200th of a second, or whatever the max X-synch speed is, and close the aperture to reduce the ambient. So from your example pictures above, you'd be working at 1/200th and f/14 to give the same ambient exposure as your fastest HSS example. Then the flash TTL takes care of increasing the flash exposure (exactly as it does in HSS mode), with the end result that the flash exposure stays the same while the ambient is reduced. Using a 2 stop ND filter to maintain the f/7.1 aperture would achieve exactly the same end - as long as the subject distance remains within the "powerband" of the flash.
    Ellis, I credit you with a better technical understanding of the HSS flash system than what you're arguing. You know all too well that there's no real ambient-to-flash ratio advantage to be had from HSS.
    HSS may be more convenient than adding an ND filter or having to actually think (heaven forbid!) about what the flash is doing, but that's it's only advantage.
     
  42. >>HSS may be more convenient than adding an ND filter or having to actually think (heaven forbid!) about what the flash is doing, but that's it's only advantage.
    The only advantage of HSS is that it bypasses sync speed requirements, to allow fill flash in bright son at equivalent exposures like 1/6400 second at f/2.8.
    The disadvantage of HSS is that the power is low (maybe 20% at most) and the range is short. And it is no longer a speedlight. HSS flash is continuous light, with no motion stopping capability. Use of HSS would seem ridiculous indoors.
     
  43. Seems to be lots of confusion in this thread about HSS.
    On Canon, HSS works with manual flash mode. It says so clearly in Canon Quick Guides for the 580EX II and 430EX II.
    I know the answer but it's exteremly easy to test if using HSS and a higher shutter speed will provide the same, more or less flash power than regular flash at max sync speed and a ND filter. You don't even need an ND filter.
    1. Go inside into a dimly lit room. Set the camera on a tripod, camera in manual mode. Flash on manual mode, full power. Shutter speed is set to max sync speed, for instance 1/250s. ISO is set to ISO 100.
    2. Take a test shot of something and adjust aperture until the exposure is good. Now take test shot A.
    3. Enable HSS on the flash. Increase shutter speed say 3 stops, for instance from 1/250s to 1/2000s. Increase ISO also 3 stops, for example from ISO 100 to ISO 800. Take test shot B.
    Compare shot A with shot B.
    We shot in a dimly lit room just to see the effect of the flash more clearly.
    Flash was at full power and the ambient exposure the same.
    Are the exposure of test shot A & B, the same or is one brighter than the other?
     
  44. Regarding "life of the flash" question … Profoto mentions it in the instructions for their OCF products (now capable of HSS with specific Canon and Nikon cameras) …
    Repeated use of HSS will result in a shorter flash tube life.
     
  45. Ah-HA! Thanks for that note abuot shorter flash tube life from Profoto.
    This has been a very informative thread for me and I really appreciate all the knowledgeable feedback and discussion. I sure know a lot more about HSS and flash in general than when I first posted.
    Thanks everybody, Bob
     

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