Flash Sync Speed w/Hassy & Rollei

Discussion in 'Medium Format' started by tim_carroll, Nov 15, 2010.

  1. Having a brain dead moment here. Got a studio shoot on Wednesday and for the first time I'm gonna use my old Rolleiflex 2.8D and Hasselblad 500CM, neither of which I've ever used with strobe before.
    Unfortunately I don't have manuals for either camera as I picked them both up used. Since they both have shutters in the lenses, as opposed to focal plane shutters, what shutter speeds will work for flash sync. IIRC the Rolleiflex will sync at all shutter speeds. And there's something you need to do with the Hassy to make it sync at all shutter speeds, because there is that shutter curtain at the focal plane.
    Am I completely off base with this?
    Any and all information will be greatly appreciated.
    Thanks,
    -Tim
     
  2. Just make sure they are set on X flash, and they sync at all speeds. You can fire the camera with the film back off to test this. You will see the flash thought the lens...if not you have a problem.
    I always tested my Hasselblads before a shoot or wedding by pulling the film back and firing the camera. That way you know the flash contacts and shutter id okay.
     
  3. The Hasselblad 500-series lenses will sync with strobes at any shutter speed.
    If you have the C-series lenses with the Compur shutter, make sure the V/M/X lever on the shutter is in the X position. The newer CF-series lenses with the Prontor shutter have no such lever; X-sync is the only option.
    Use the method Russ described to confirm operation.
    - Leigh
     
  4. Sync will be at all speeds if you are tethered by a PC cord, some of the wireless systems do have a very small delay and those will cause you to move to slower shutter speeds, but you will have to test this or find out the manufacturer's specs. The other consideration is going to be your flash units. Not so much the sync speed, but most studio flash units will not produce the same amount of light at 1/500 of a second as you will get from say a 1/60 shutter speed. The flash duration of your units will be a factor in flash output at different shutter speeds. If you have a good flash meter, you will actually be able to measure the output at different shutter speeds.
    Good luck.
     
  5. Good points, John. I hadn't considered the wireless trigger delay.
    I normally run my lenses at 1/125 for strobe work, unless the ambient light level dictates a faster speed.
    Most modern strobes will have durations of <1/1000 second, but that should be confirmed for the specific units in use if fast shutter speed is needed.
    - Leigh
     
  6. Any speed will do, but I find the Compur shutters to be finicky sometimes, so definitely test the lens before you go out and shoot anything important.
     
  7. Thanks for all the input.
    I will be using a Dyna-Lite unit and be attached by a sync cord, no wireless. I do have a Sekonic Flash Meter, so as long as I meter for the shutter speed I am using, I should be fine?
    Also, it's in a studio with negligible ambient light, so I'll set things for the strobes.
    Best,
    -Tim
     
  8. You should be fine, but like Leigh said, I also used about 1/125 as a normal shutter speed. I do realize that many flashes are higher speed, but there is a difference in flash duration specs, depends on the basis with the t.1 being the one to pay attention to. None of my studio strobes had a t.1 as fast as Leigh suggests, but the meter should tell you that.
    t.5 duration is very misleading and significantly shorter on most flashes. If you care to know, I found this link just now, but haven't read it all, just has a nice graph and the first paragraph seemed sound.
    http://jerrycentral.com/2008/12/18/flash-duration/
     
  9. t.5 duration is very misleading and significantly shorter on most flashes.​
    While the information on the website is correct regarding power distribution, I believe his interpretation thereof is way off base.
    The t.5 duration is a very good average. That's why the flash manufacturers use it.
    The t.1 duration is 1/32 power, which is 5 STOPS down. Who cares how long it is?
    And in the example given, the t.1 duration is 1/150, which is still faster than a 1/125 shutter.
    - Leigh
     
  10. Leigh, I just know from experience that you have to pay attention to the t.1 or you get movement when you think things should be frozen--I didn't read this article, as I said, but from pretty broad experience shooting professionally, and a lot for the big sports shoe companies (My studio was in Portland for years--coincidentally, in the 3 stripe companies former headquarters) that this is the case. I have a Broncolor color meter than reads both of these values and tested several "fast" lights because tests against the t.5 values did have some movement where I didn't expect it. There is enough light, cumulative, below the t.5 that you can get into these sorts of problems. Although I have never tested them, I don't think this is an issue with most on camera type strobes, which seem to have much faster flash durations.
    As long as you meter your lights at the shutter speed you are expecting to use, it doesn't matter what the t.1 or t.5 actually is. In my case, I didn't generally see the light fall off until 1/250th with most of my lights. On one that was a 4800ws light, it was after 1/60th, but as I said, it doesn't matter if you meter your lights at the intended, and used, shutter speed.
     
  11. Hi John,
    I don't doubt that you can define certain scenarios under which the t.1 value would be of significance.
    As with anything else in this world, there are no universal truths (save this one ;-).
    - Leigh
     
  12. I do have a Sekonic Flash Meter, so as long as I meter for the shutter speed I am using, I should be fine?​
    The shutter speed does not affect the flash part of the exposure, only the part provided by the ambient light. However:
    Also, it's in a studio with negligible ambient light​
    So the shutter speed will have negligible effect.
     
  13. Steve, as I mentioned above, the shutter speed can have a much larger effect than one might think, depending on the flash duration. It can actually be fairly significant.
    Leigh, I have been shooting with studio flash for over 20 years and have shot a significant amount of motion work. Flash duration, t.1 matters, t.5 is a very misleading number and is used by the mfg's because it makes their flash units look better--again, we are talking studio flash systems here, not Canon or Nikon camera flashes.
     
  14. That's fine, John. I've been doing studio work for over 50 years. And yes I'm talking about studio strobes, not on-camera units or Vivitars.
    I was also a warranty service station for Novatron for several years, so I'm reasonably knowledgeable in the operation of "real" strobe equipment and systems.
    I strongly disagree with your assertion that t.5 is used as a marketing gimmick. If you'll take a look at the charts on the website, you'll see that the t.1 duration is exactly twice the t.5 duration in every case. Flash decay characteristics are pretty uniform. So specifying either t.1 or t.5 implies the other with a high degree of accuracy.
    There are few instances where the duration of output 5 stops down matters. Some occasions... yes; the majority of applications... no.
    - Leigh
     
  15. Correction...
    The t.1 is three times the t.5 duration, not twice.
    - Leigh
     
  16. Leigh, "real"? Not sure what that means-- should I be insulted (do you know something about my equipment)? Anyway, flash duration is not always specified, or hasn't been over time, as either t.5 or t.1, although if it was t.1 they usually did say so. The important point here is that you need to know your lights in this regard especially if sync is capable up to speeds of 1/500th to 1/800th of a second. Just assuming you are getting the same amount of light to your film, because it is flash, at 1/60th or at 1/500th will set you up for some disappointment with many systems out there. Maybe we can agree on that at least.
     
  17. Hi John,
    By "real" I just meant AC-powered studio power packs and heads, or monolights, as opposed to battery-powered units. No offense intended.
    I certainly agree that you must evaluate all your equipment in the context of the requirements of the application. It's important to identify systemic sensitivities and ensure that the selected equipment will meet those with a comfortable safety margin.
    - Leigh
     
  18. Can anybody tell, if i have Hassy with CF lense, will it works fine on all shutter speeds if i'd use cheap wireless sync for studio strobes (for example something from aliexpress)?
     
  19. Not necessarily.
    All radio triggers introduce a short delay, due to encoding/decoding times. This has nothing to do with radio propagation delay, which is practically instantaneous. It doesn't matter if you use cheap Chinese-made triggers or overpriced American-made ones (naming no names). They're all much the same.

    The short version is that you'll lose a bit of light at higher shutter speeds < 1/125th s. This will only amount to 1/3rd to half-a-stop, but it still needs to be taken into account for critical work.

    In fact a shutter speed of 1/500th s will likely lose you a small amount of flash exposure, even using a direct cable connection to the strobe. Because the total decay time of electronic flash at full power is several milliseconds, and a lot longer than popular myth would have you believe.

    The flash time also depends on the circuitry of the flash, with some models giving longer flash times at lower 'power', and others giving much shorter times as the light output is reduced. RTFM is always a good plan!
     
    Last edited: Jan 12, 2020
  20. Shutter speed settings on a Sekonic flash meter have no effect on the flash reading.
     

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