Re: High-Speed Sync for Speed Graphic
I tried 2K's a while ago, no thank you!
Quote:
Originally Posted by
LabRat
The ez, old school way is to use bright hot lights, and use any speeds you can meter...
Steve K
Re: High-Speed Sync for Speed Graphic
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Originally Posted by
Tin Can
I tried 2K's a while ago, no thank you!
Hey, Hurrell did it all the time!!!
But the poor subject might be scared of the "interrogation", or be cooked like BBQ...
Steve K
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
Oren Grad
...if the HSS setting is made on the flash rather than from the camera's menu, and the exposure mode is set for manual or for AE controlled via on-flash sensor rather than camera-controlled TTL AE, there might not be anything that needs to be communicated between camera and flash other than sync closing. In theory the duration of the HSS pulse sequence might be customized to different camera bodies via some signal through the dedicated flash contacts, but in practice I suspect that it's a fixed parameter.
Just a guess, but I would think the manufacturer would design a system in which the strobe was aware of the shutter speed so it didn't have to keep flashing once the shutter was fully closed. Big difference between asking the strobe to cover 1/500 seconds versus 1/8000.
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
AeroK
Just a guess, but I would think the manufacturer would design a system in which the strobe was aware of the shutter speed so it didn't have to keep flashing once the shutter was fully closed. Big difference between asking the strobe to cover 1/500 seconds versus 1/8000.
I don't think that is what happens. The shutter always takes the maximum sync speed (say 1/250th) to open then fully close at high speeds. The slit between the shutters (the shutter is never fully open at higher speeds) creates the higher shutter speeds. So the burn of the HSS flash is always 1/250th or whatever but at higher speeds the maximum power is cut as the gap between the shutters narrows. The shutter curtains themselves always travel at the same speed it's the timing of the second curtains release that controls shutter speed. So what you would need to look for is a flash that burns for the amount of time it takes for the the speed graphic shutter to fully open and fully close. I don't know how long that takes with a speed graphic but if it takes 1/30 with a Pentax 67 I would guess it would take a 1/15 or an 1/8 second with a Speed. I don't know where you would find a flash that burns for that long.
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
AeroK
Just a guess, but I would think the manufacturer would design a system in which the strobe was aware of the shutter speed so it didn't have to keep flashing once the shutter was fully closed. Big difference between asking the strobe to cover 1/500 seconds versus 1/8000.
Quote:
Originally Posted by
Tobias Key
So what you would need to look for is a flash that burns for the amount of time it takes for the the speed graphic shutter to fully open and fully close. I don't know how long that takes with a speed graphic but if it takes 1/30 with a Pentax 67 I would guess it would take a 1/15 or an 1/8 second with a Speed. I don't know where you would find a flash that burns for that long.
What Tobias said. The relevant parameter isn't the marked shutter speed, it's the curtain travel time, because that's the duration during which some part of the sensor or film is being exposed.
Re: High-Speed Sync for Speed Graphic
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
Tobias Key
...the shutter always takes the maximum sync speed (say 1/250th) to open then fully close at high speeds. The slit between the shutters (the shutter is never fully open at higher speeds) creates the higher shutter speeds.
That makes sense Tobias. I think you're probably right. Thanks.
...doug
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
Tobias Key
...the shutter always takes the maximum sync speed (say 1/250th) to open then fully close at high speeds...So what you would need to look for is a flash that burns for the amount of time it takes for the the speed graphic shutter to fully open and fully close.
I'm still on my first cup of coffee for the day, but how about this: Assuming Tobias is correct and that the total duration of the HSS flashes are within a 1/250-second window, then I should be able to use the Speed Graphic's focal-plan shutter at 1/250 or faster. I just need to figure out how to trigger the flash. Might start experimenting today. ...doug
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
Oren Grad
In theory the duration of the HSS pulse sequence might be customized to different camera bodies via some signal through the dedicated flash contacts, but in practice I suspect that it's a fixed parameter.
Thinking about this some more, the frequency and magnitude of the pulses might be tailored to the shutter speed, though any of the sequences should work for a much slower curtain shutter - *if* the overall duration of the pulse sequence is long enough, which it probably isn't. Oh, well.
Re: High-Speed Sync for Speed Graphic
Quote:
Originally Posted by
AeroK
I'm still on my first cup of coffee for the day, but how about this: Assuming Tobias is correct and that the total duration of the HSS flashes are within a 1/250-second window, then I should be able to use the Speed Graphic's focal-plan shutter at 1/250 or faster.
Again, it's the curtain travel time that matters. This is the HSS total duration you'd need:
Quote:
Originally Posted by
Tobias Key
...I would guess it would take a 1/15 or an 1/8 second with a Speed.