Hi Speed sync vs Leaf shutter sync at any speed.

Discussion in '35mm Cameras' started by Patrick L., Nov 16, 2003.

  1. Patrick L.

    Patrick L. Guest

    What are the pros and cons of each?

    Patrick L., Nov 16, 2003
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  2. Patrick L.

    George Guest

    Not trying to be facetious, but with high speed focal plane shutter sync you
    actually have to think which DOES leave room for error should you forget or
    come to the wrong conclusion.
    George, Nov 16, 2003
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  3. Patrick L.

    Alan Browne Guest

    Leaf shutters (1/500 max speed typical) operate close to the slowest
    speed of a studio flash (eg: total or near total discharge of a large
    flash is nearly 2 ms.) The open/close pattern of a leaf shutter does
    not give a 100% even time of exposure to the entire surface of the film,
    but the difference is so small as to be completely negligeable. Others
    might comment with more detail than I can on the fact that some (many?)
    MF cameras have two shutters, one in the body that is slow, and the leaf
    shutter for the actual exposure. Leaf shutters are part of the lens, so
    every lens for the camera has a shutter mechanism. A seeming
    unneccesary duplication v. focal plane. OTOH, a focal plane shutter in
    a MF camera would need to be larger than that of a 35mm SLR, so the
    small leaf shutter in the lens makes more sense for the engineers as
    speed requirements go up. Several MF cameras emply focal plane
    shutters. (Mamiya and others).

    Focal plane shutters in the higher end SLR's such as the EOS-1v, Maxxum
    9 and the F5 (and few others) operate flash-sync as fast as 1/300 ... a
    mere 2/3 stop slower than a 1/500 leaf shutter.

    [[ A comment: In a studio with moderate ambient lighting, that ambient
    lighting is usually not even a small fraction of the exposure on film.
    So whether the shutter duration is 1/125, 1/250 or 1/500 does not matter
    much to the exposure. Consideration for hotlights that are in the
    scene, is another matter, of course. The real advantage of a high
    shutter speed is the exclusion of minor 'ghosting' effects from the
    subjects movement, and this only occurs in very high ambient lighting
    and/or with faster film and fat apertures.]]

    As you surely know, a focal plane shutter has two curtains, one that
    opens to expose the film and a second that closes to end the exposure.
    The speed of travel of the curtains is always the same regardless of the
    selected "shutter speed". What changes is the interval between the
    first and second shutter movement. (Why Canon has "T" settings instead
    of "S" settings, but I digress).

    The movement of the 2nd curtain begins at the interval indicated by the
    shutter speed and travels at the same speed as the 1st curtain. Max
    sync, as I'm sure you know, is the speed at which the 1st curatin has
    completely opened, but the 2nd curtain hasn't yet begun travel and there
    is time to start the flash, let it finish and then start the 2nd
    curtain. Altogether an elegant system. As the sync speed of cameras
    rises (from the old fashioned 1/60 to 1/125 to 1/200 and now 1/300) the
    actual travel velocity of the curtains has had to increase.

    1/8,000 as a top shutter speed is present in high end SLR's, and the
    Maxxum 9 sports a 1/12,000 top shutter speed. those curtains are moving
    right quick!

    (Some people have even raised the issue that at very high speeds, the
    slit must be so narrow as to introduce interference fringes. I've never
    seen this substantiated).

    High Speed Sync /High Speed Flash (HSS)
    HSS works by controlling the ouput of the flash such that it's power
    function over time is very nearly flat (as opposed to the "normal" flash
    function which peaks very rapidly and then decays quickly according to
    the capacitor discharge.) The HSS flash controls this by turning the
    flash on and off at a high pulse rate, never allowing it anywhere near
    peak. So the first thing with HSS is that less than full punch will be
    available...IN ALL CASES... because the 'tail' of the discharge curve
    cannot be used, it is not powerful enough to maintain the flat part of
    an HSS discharge.

    In the interest of having the flash "on" at the time the first curtain
    is opening, the flash begins a bit early. So return light from the
    flash is lost and can't help the exposure, at all. Then it gets worse....

    ...imagine that the slit between 1st and 2nd curtain is 1/4 the height
    (or witdth) of the frame. That means that 75% of the current flash
    output (already much less than full power) is being wasted during the
    exposure. (Light from the flash hits the entire scene, but only 1/4 of
    that is being used)

    It is no surprise at all to see that a GN 56 flash (Minolta 5600HS) is
    only a GN 3 flash at 1/8,000 (50mm). Even at 1/1,000 and 50mm it is a
    measley GN of 9. At 1/500, it is GN 12... same as the tiny built in
    flash on most Minolta SLR's.

    HSS, is plain inefficient. But is it useful?

    HSS *is* useful in some situations, like fill flash for a backlit scene
    for which high speed and a shallow DOF is desired.

    I've had HSS flashes for 3 years. I have used them as HSS flashes less
    than 5 times. ND filters can get your aperture opened up in bright
    lighting while maintaining relatively high shutter speeds. If you need
    to do precision high speed flash photography (relatively high power and
    flash durations of less than 1 ms down to around 100 usec) then you
    should look at either more powerful studio strobes, or scientific strobes.

    A point worth noting is that the focal plane shutter design lends itself
    to the HSS method as it is a two curtain system; HSS would not be
    possible with a leaf shutter.

    Conclusion: Fastest sync photography is with leaf-shutters; fastest
    flash photography is with HSS, but the exposure GN drops dramatically
    with shutter speed above sync.

    Systems like the Maxxum 7 with 5600HS allows multiple flash heads in HSS
    mode to be controlled by the camera (and I believe the Canon 550EX does
    too, not sure about Nikon HSS).

    I hope that was just enough and not too much.

    Alan Browne, Nov 17, 2003
  4. Patrick L.

    Patrick L. Guest

    Very informative, Alan, thank you.

    Patrick L., Nov 17, 2003
  5. Patrick L.

    Gordon Moat Guest

    Leaf shutter lenses (mostly medium format and large format in newer
    gear) can often be more expensive. A backup for a leaf shutter lens
    system could be another lens, instead of another body, since the body
    could be a much simpler device, and theoretically less prone to
    breakdowns. Obviously, this is not always true in practice.

    If you want to do fill flash quite often, being able to sync at any
    shutter speed is nice. With focal plane systems, some will reliably do
    1/250 without much trouble, though slower can be more reliable for
    results (a few do faster). High speed sync tries to get around that by
    pulsing the flash, though the results are not necessarily better than
    using the fastest normal sync setting. Many leaf shutter systems will
    easily do 1/500 sync, a few slightly faster in some settings, and
    several choices in the Rollei 6000 series do 1/1000. Getting the full
    flash power at those settings is easier with the leaf shutter system
    than the focal plane system

    If your subject moves at slow sync speeds, you can get a blur of them on
    the image. While this can be nice for creative effects, or to show
    motion, it can be a distraction in more static shots. With high speed
    sync, a similar blur distraction can occur with subject motion, and can
    look similar to a repeating flash image. There are ways to adjust for
    this, depending upon your camera system and lighting gear.

    Old style bulb flashes sometimes had a long enough burn time to be
    useful at faster shutter setting, without having diminished power.
    Unfortunately, the less convenient availability of bulb flash systems
    limits this for modern photographic uses.

    I think some of the other posters covered some other issues quite well.
    If possible to have both system types, one could exploit the advantages
    of each. I think it is a good idea to have at least one leaf shutter
    system dedicated to fill flash imagery. A really low cost way to do that
    would be to acquire one of the early 1970s Japanese 35 mm rangefinder
    cameras, even though the fixed lens might seem to be a limitation.


    Gordon Moat
    Alliance Graphique Studio
    Gordon Moat, Nov 17, 2003
  6. Patrick L.

    Patrick L. Guest

    My Oly E-10 syncs at any shutter speed, up to 1/640. Once, on a yacht, I
    had the occasion where teh interior was 3 stops darker than the exterior,
    and I was shootiong a F/5.6 at 1/500 with flash. Comes in handy, that E-10.

    Patrick L., Nov 18, 2003
  7. Patrick L.

    Alan Browne Guest

    Ahem. The E-10 has a beamsplitter, no mirror, so not really "sync",
    just the light that happens to be there after the shutter is depressed.
    .... if flash, so much more.

    Your 'shot' would harldy look different at 1/60, as the duration of the
    flash is on the order of 1 ms (1/1000). Ambient light ("fill") would
    have been a bit better, that is all.

    Think of flash shots as double exposures. One ambient, one flash. And
    the flash portion is independant of shutter speed as long as the flash
    starts when the entire film (or CCD) is ready to receive it.

    Alan Browne, Nov 18, 2003
  8. Patrick L.

    Gordon Moat Guest

    Not familiar with that camera, but I suppose if it is a leaf shutter design,
    then that is quite within reason. The B&H Digital SourceBook I got today does
    not list your Olympus, so it must be discontinued. There is six pages on the
    new E-1, but no mention of flash sync, other than the HSS of the FL-50 flash
    (good up to 1/4000). No mention of maximum file size either . . . oh well.

    Olympus has been very innovative in the past with flash control in their film
    SLRs, so it would make sense to build some nice features into their direct
    digital cameras. 1/640 is a really odd speed, and definitely not a normal stop,
    nor setting. This is only 1/3 stop faster than 1/500, so not a great stretch
    over many older medium format leaf shutter systems.
    Definitely there are times when 1/500 and flash can be a nice combination.
    Something like the Rollei 6008 could have done f4 at 1/1000 under the same
    conditions, assuming the same flash power. Of course, the flash unit is a
    bigger issue, and the settings could vary quite a bit more with a powerful
    enough unit.

    The Metz 54 or Sunpak 120J, and some of the larger Quantum flash units are
    quite powerful. If you think you will be needed to do lots of fill flash, or
    unusual lighting situations, get a really good and powerful flash system.
    Quantum also make battery boosters for lots of other companies flash units.


    Gordon Moat
    Alliance Graphique Studio
    Gordon Moat, Nov 18, 2003
  9. Patrick L.

    deathwalker Guest

    Thats a point how do digital cameras operate a shutter? Is it softwaresimply
    saying i will take this continious stream from and capture this moment now
    or is there still a shutter in front of the sensor? If the former then
    theoretically flash sync is no longer a problem.
    deathwalker, Nov 18, 2003
  10. Patrick L.

    Tom Thackrey Guest

    Both. Some camera's have an 'electronic' shutter (usually those that let you
    use the LCD display to compose the image). Most DSLRs have a mechanical
    shutter. In either case flash sync is a 'problem' in that the shutter needs
    to be 'open' when the flash fires. The exception is high speed sync with
    focal plane shutters where the flash fires repeatedly to extend the flash
    duration to match the time it takes the shutter curtain to travel across the
    film gate.
    Tom Thackrey, Nov 18, 2003
  11. Patrick L.

    Patrick L. Guest

    I did a few shots at 1/60, but After viewing a few images on my LCD,
    showing the washed out light coming through the Yacht's windows (which, are
    all over the place, a huge part of every image), since I was shooting at
    F/5.6, the proper shutter speed was 500 for the blue sky and ocean in the
    background, and it made a big difference. See, on a yacht, the background,
    just outside the windows, is that beautiful blue ocean and sky, which,
    compositionally speaking, given that I'm on yacht, I felt the exterior
    belonged, properly exposed, in the shots. Perhaps, at some other venue, it
    would not have been as important.

    Patrick L., Nov 18, 2003
  12. Patrick L.

    Patrick L. Guest

    I certainly agree, and since I do nothing but fill flash on weddings, I
    really understand the importance of needing more flash power. I'm just a
    toddler with my E-10 and Fl-40, but, then again, they get me for bargain
    rates, since I don't have much experience.

    My dream camera is the Hassy H1 (or Mamiya 645) with two Qflash units and an
    assistant for weddings. But my piggy bank ain't there, yet. Some day....

    Patrick L., Nov 18, 2003
  13. Patrick L.

    Alan Browne Guest

    Fair enough, you achieved what is important, balance. My comment above
    was just on the point that all flash shots are double exposures ... one
    for the ambient and depending on shutter speed, and the other for the
    flash which is typically faster than 1/1000 regardless of shutter speed.
    That is what is key to understand.

    Alan Browne, Nov 19, 2003
  14. Patrick L.

    Alan Browne Guest

    oops: boobed that up didn't I? However I believe the E-10 has an
    electronic "shutter" through the CMOS sensor, so the logic stands.

    Alan Browne, Nov 23, 2003
  15. Patrick L.

    deathwalker Guest

    Thats hardly a problem.
    Focal plane shutter problems are the fact that after a certain speed the 2nd
    curtain follows the first before the first has got to the other side so you
    can't expose the whole frame with a single burst. AFter the mirror has come
    up the shutter may fire at any time seeing as flash durations are 1/10,000 -
    1/50,000 of a second. so 1/250 would seem like an electronic eternity.

    "for an android that seems like a lifetime sir".
    deathwalker, Jan 9, 2005
  16. Patrick L.

    Zico Guest

    Zico, Jan 9, 2005
  17. Patrick L.

    Chris Brown Guest

    DSLRs have similar shutter lag to their 35mm counterparts.
    Similar to their equivalent 35mm models. My EOS 10D, for example, syncs at
    Chris Brown, Jan 9, 2005
  18. Patrick L.

    Zico Guest

    Zico, Jan 9, 2005
  19. Patrick L.

    Chris Brown Guest

    The technology exists. Some professional model DSLRs have higher speed sync,
    but you have to pay for it. If you want better than that, you might want to
    investigate medium format digital + leaf shutters, which will sync at any
    speed (although leaf shutters can't do the really high speeds at all).

    And if you want to minimise shutter lag, you might want to look into
    something without a moving mirror, such as an Epson RD-1, or the digital
    Leica M when they eventually get round to releasing it.
    Chris Brown, Jan 9, 2005
  20. Patrick L.

    Matt Clara Guest

    The D70 has a 1/500th sync speed. As I recall, it does use an electronic
    shutter for those speeds over 1/250th. I could be wrong on that, though!
    (Not the sync speed, just the way it operates.)
    Matt Clara, Jan 9, 2005
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