Hi speed sync Pentax *ist and AF 360FGZ

I recently bought a Pentax *ist and AF360FGZ flash and am
impressed by the flash in combination with the *ist. Hi speed
flash sync is available at any shutter speed. Can anybody
explain how on earth this is achieved as I can not find an
explanation of the actual workings of the process in any
Pentax manual (camera or flash) or any of the photography
manuals (even checked Michael Freeman's "Light") but to
no avail.

I think there are some clues in the two manuals. What seems to happen is that the flash fires several times, exposing strips of the negative, as the shutter apperture traverses the negative. The total power available from the flash decreases as the shutter speed is raised, so it fires smaller flashes more frequently, as it hasn't the inverter power to give full power flashes in quick sequence. I'm not sure how it ensures that the flash exposure is constant across the whole negative, as I would have thought that there would be some overlap between the strips.

Don't know if anyone has any better ideas?

Cheers

Taliety

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Cheers

Malcolm

Life? Don't talk to me about life!