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Delay the flash untill a button is pressed, during long exposure

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Offline bongo_bingo

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Delay the flash untill a button is pressed, during long exposure
« on: 21 / November / 2008, 09:57:31 »
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Hello all,
I was mind if there's a way, via script or other, to delay the flash untill a button is pressed, during long exposure.

Sorry for bad english explanation :-[

bye
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Offline PhyrePhoX

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #1 on: 25 / November / 2008, 19:00:40 »
well, no.
once the camera is in "exposure mode", you cannot influence the behaviour.
however, there is experimental code somewhere that lets you fire the flash on button press, this might be useful for what you want to do. however, there is no working code in the current trunk that allows such a thing.
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Offline bongo_bingo

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #2 on: 26 / November / 2008, 02:19:58 »
Thanks for the answer PhyrePhoX,
are you talking about Developer-friendly / experimental branch (dataghost) ?
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Offline PhyrePhoX

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #3 on: 26 / November / 2008, 04:14:41 »
yes, exactly. though i am not sure that he implemented it in there, we only talked about that in irc.
it definitly is possible firing the flash via a function call in asm.
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Offline bongo_bingo

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #4 on: 27 / November / 2008, 07:24:06 »
this ability would have a very creative use.
I'll try to resume dataghost thread, maybe we'll have some chance to have a "strobist branch".
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Offline PhyrePhoX

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #5 on: 27 / November / 2008, 07:55:10 »
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Offline bongo_bingo

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #6 on: 27 / November / 2008, 13:38:19 »
Reading s-series - enable flash during video recording for still images seems that you and fudgey have already
had some results in video mode.
What is missing to adapt it to photo mode?
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Offline PhyrePhoX

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #7 on: 27 / November / 2008, 13:55:50 »
no, unfortunately we didnt have any results in video mode, just theory spoken off of our minds. assembler is way to complicated for me to understand, so i guess without a genius asm guy who also is interested in this field this will be very hard to accomplish :)
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Offline ewavr

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #8 on: 27 / November / 2008, 14:58:20 »
Hey, no problem here!

In camera firmaware we have a lot of functions to control the flash:

EF.StartEFCharge(some address) - starts flash charge (works fine with NULL argument)
EF.StopEFCharge(void) - stops flash charge
int IsStrobeChargeCompleted(void) - verify full charge of flash - already in CHDK
EF.StartInternalPreFlash(some_struct *) - starts the flash in different modes (described here)

Example of such video - http://ewavr.nm.ru/chdk/1.avi (flash power is 10 units). Maybe power consumption in this mode is indescribable (huge).
« Last Edit: 27 / November / 2008, 14:59:53 by ewavr »
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Offline PhyrePhoX

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Re: Delay the flash untill a button is pressed, during long exposure
« Reply #9 on: 27 / November / 2008, 15:22:38 »
wow, nice, thanks for the summary.
so this could end up in trunk. but i think these functions should only be enabled for example with an extra submenu, like "unlock potentially harming functions". if the checkbox is enabled, you can use these functions from ubasic/lua.
do you think you can also help here: s-series - enable flash during video recording for still images ?
i want to enable the flash while it is normally not able to being used, somewhere in the firmware of the s-series cameras has got to be some check if video running -> disable flash.
i will try if i can charge and fire the flash using the commands you posted while in video mode, perhaps i can sync it with pressing of the shutter button (but i guess it will not be fast enough) (i guess i just need to grab the adresses of these functions from IDA).
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