Flash sync - followup question

I did find out that the Kiev 60 will not fire the "X" sync at speeds
above 1/30. I assume this is true of other MF FP SLRs as well. But as
I was thinking about how to (or who to go to) modify a Kiev 60 to fire
the flash at higher speeds, I realized that the timing would have to
change as well. Today, I assume the Kiev 60 fires the flash after the
first shutter curtain has completely opened. If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?
Thanks

In message , writes
I did find out that the Kiev 60 will not fire the "X" sync at speeds
above 1/30. I assume this is true of other MF FP SLRs as well. But as
I was thinking about how to (or who to go to) modify a Kiev 60 to fire
the flash at higher speeds, I realized that the timing would have to
change as well. Today, I assume the Kiev 60 fires the flash after the
first shutter curtain has completely opened. If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?
Thanks


X sync on a focal plane shutter fires the flash when the first shutter
curtain is open, but the second has not yet moved. At higher speeds you
will need the output of the flash to remain constant for the time it
takes the gap between the shutter curtains to cross the film. This makes
it a (very) bright torch.
--
----------------------------
Paul Friday

In message , writes
I did find out that the Kiev 60 will not fire the "X" sync at speeds
above 1/30. I assume this is true of other MF FP SLRs as well. But as
I was thinking about how to (or who to go to) modify a Kiev 60 to fire
the flash at higher speeds, I realized that the timing would have to
change as well. Today, I assume the Kiev 60 fires the flash after the
first shutter curtain has completely opened. If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?
Thanks


X sync on a focal plane shutter fires the flash when the first shutter
curtain is open, but the second has not yet moved. At higher speeds you
will need the output of the flash to remain constant for the time it
takes the gap between the shutter curtains to cross the film. This makes
it a (very) bright torch.
--
----------------------------
Paul Friday

The 'best' time to fire the flash is when the entire negative area is
uncovered by the focal plan shutter. That is when the first curtain has
completed its travel, and before the second curtain has begun to move. The
flash duration is very short. Anything else and the negative area will not
be fully uncovered to benefit from the effects of the momentary pulse of
light from the electronic flash unit. A faster synch time means the
curtains would have to move very much faster which is an expensive
engineering problem.

wrote in message
...
I did find out that the Kiev 60 will not fire the "X" sync at speeds
above 1/30. I assume this is true of other MF FP SLRs as well. But as
I was thinking about how to (or who to go to) modify a Kiev 60 to fire
the flash at higher speeds, I realized that the timing would have to
change as well. Today, I assume the Kiev 60 fires the flash after the
first shutter curtain has completely opened. If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?
Thanks

The 'best' time to fire the flash is when the entire negative area is
uncovered by the focal plan shutter. That is when the first curtain has
completed its travel, and before the second curtain has begun to move. The
flash duration is very short. Anything else and the negative area will not
be fully uncovered to benefit from the effects of the momentary pulse of
light from the electronic flash unit. A faster synch time means the
curtains would have to move very much faster which is an expensive
engineering problem.

wrote in message
...
I did find out that the Kiev 60 will not fire the "X" sync at speeds
above 1/30. I assume this is true of other MF FP SLRs as well. But as
I was thinking about how to (or who to go to) modify a Kiev 60 to fire
the flash at higher speeds, I realized that the timing would have to
change as well. Today, I assume the Kiev 60 fires the flash after the
first shutter curtain has completely opened. If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?
Thanks

"Fred Leif" wrote in message
...
The 'best' time to fire the flash is when the entire negative area is
uncovered by the focal plan shutter. That is when the first curtain has
completed its travel, and before the second curtain has begun to move.

*sigh*, I'm so glad I still use flashbulbs.

"Fred Leif" wrote in message
...
The 'best' time to fire the flash is when the entire negative area is
uncovered by the focal plan shutter. That is when the first curtain has
completed its travel, and before the second curtain has begun to move.

*sigh*, I'm so glad I still use flashbulbs.

wrote:

[...] If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?

Yes. The flash should be ignited the moment the first curtain starts to
travel.

It should have reached full level the moment the first bit of film is
uncovered. Which was a problem using flash bulbs, but should not be a
problem with electronic flash units.
It will have to keep output at a constant level during the entire burn
time/travel time to get even exposure.
And of course using shorter times/narrower slits will result in less
exposure.

wrote:

[...] If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?

Yes. The flash should be ignited the moment the first curtain starts to
travel.

It should have reached full level the moment the first bit of film is
uncovered. Which was a problem using flash bulbs, but should not be a
problem with electronic flash units.
It will have to keep output at a constant level during the entire burn
time/travel time to get even exposure.
And of course using shorter times/narrower slits will result in less
exposure.

Sort of like 'reinventing' the flash bulb ??

"Q.G. de Bakker" wrote in message
...
wrote:

[...] If you had a flash unit
that could deliver say 1/25 sec of light, then the best time to fire the
flash would be at the start of the first shutter curtain's travel. Am I
correct?

Yes. The flash should be ignited the moment the first curtain starts to
travel.

It should have reached full level the moment the first bit of film is
uncovered. Which was a problem using flash bulbs, but should not be a
problem with electronic flash units.
It will have to keep output at a constant level during the entire burn
time/travel time to get even exposure.
And of course using shorter times/narrower slits will result in less
exposure.