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Thanks, and G9 motion detection with flash

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Offline mgxxx

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Thanks, and G9 motion detection with flash
« on: 30 / January / 2009, 07:46:07 »
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I still find this whole CHDK/SDM business extraordinarily rich with generousity, thanks all for sharing.

 Could I ask about Motion detection and flashes. I am using the latest SDM download and on Microfunguy's suggestion got fast md working fine( Fudgey's I presume) .  My use is for nocturnal monitoring of  small mammals.  Unfortunately the internal cut-off filter inhibits using IR LEDs for light sources so I will try using the more visible LEDS (eg brake lights in cars) for motion detection. But it would be very useful if I could use flash as well ( perhaps with a red filter over the flash).

Is it possible to  synch the fast motion detection capture with the camera's flash?

with thanks

Terry
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Offline barret

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Re: Thanks, and G9 motion detection with flash
« Reply #1 on: 30 / January / 2009, 09:42:55 »
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Unfortunately the internal cut-off filter inhibits using IR LEDs for light sources
Is that for sure? I've heard that despite the existence of IR cut-off filter, you can still record IR light, with an R72 filter for example. I'm not sure about G9, but I've done it with S3. Have you tried using IR filters?
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Offline Microfunguy

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Re: Thanks, and G9 motion detection with flash
« Reply #2 on: 30 / January / 2009, 09:54:01 »
Quote from: mgxxx on 30 / January / 2009, 07:46:07
the internal cut-off filter inhibits using IR LEDs for light sources

I have just plugged the A/V output of my A620 into the TV and pointed the IR remote at the camera.
I see the very bright pulses whenever I press a button.

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it would be very useful if I could use flash

No problem.
Fit a IR filter over the camera flash (and the external flash if you wish) and use Firefly 3 http://www.fireflyelectronics.co.uk/pages/info.htm

It ignores the preflash, works well.

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Is it possible to  synch the fast motion detection capture with the camera's flash?

Not sure what you mean, is there a synch problem  ?

To detect nocturnal animals, surely you will need a continuous IR light source ?

In SDM 1.76, you will be able to turn-off the header at the top of the screen if you are using camera for ordinary 2D photography.


David
« Last Edit: 30 / January / 2009, 10:13:56 by Microfunguy »
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Offline mgxxx

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Re: Thanks, and G9 motion detection with flash
« Reply #3 on: 30 / January / 2009, 18:48:59 »
IR cut-off.  I haven't been able to track down the  wavelength that the Canon IR cut-off filter works at.  People have used R72 filters but with long exposure times.   I have used a bank of IR LEDs  (I think the wavelength is ~850nm) for video monitoring but this bank simply doesn't throw enough light for the G9 ( even at max iso). Sure if I point the camera at the LEDs they can be seen but pretty weakly. I see that you can get dig cameras converted ( the cut-off filter window changed) so that there is no filtering of IR.

So, for motion detection I need some sort of low level continous light ( I wanted to use the IR LEDs) then use the flash to get good exposure of the animals.  I accept now I might have to go to a lower wavelength red light source for the continuous light source but there will be a balance between what th e camera the animals are sensitive to.

But the main issue is the flash and this where my newbieness comes in to play. Thus far on fast motion detection, the flash fires well after the image has been captured. On the G9 with all the settings in place, the detection and capture is very fast, but I don't know whether its possible to have the flash fire immediately the motion is detected.
Terry

Thanks for your responses thus far.
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Offline Microfunguy

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Re: Thanks, and G9 motion detection with flash
« Reply #4 on: 31 / January / 2009, 05:34:35 »
Quote from: mgxxx on 30 / January / 2009, 18:48:59
on fast motion detection, the flash fires well after the image has been captured. ...I don't know whether its possible to have the flash fire immediately the motion is detected.

Do you really mean after the image has been captured or after the movement has been detected ?

The flash MUST  fire when the photo is taken, we have no control over that.

Might be better to post this 'problem' as a new topic that includes the words 'motion detection'.

MX3 and/or fudgey may then see it before it gets 'buried'.


David
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Offline fudgey

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Re: Thanks, and G9 motion detection with flash
« Reply #5 on: 31 / January / 2009, 06:02:49 »
Quote from: Microfunguy on 31 / January / 2009, 05:34:35
MX3 and/or fudgey may then see it before it gets 'buried'.

Can't help really, sorry. My cam usually crashes if I enable flash with MD (for what I can remember it crashes after the flash fires, which is when all them reload procedures with display&sensor OFF happen). Other cameras have been reported to have better success.

I really don't see a reason why MD would be able to delay the flash, but then again I have no clue why my cam crashes while at it it either.
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Offline mgxxx

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Re: Thanks, and G9 motion detection with flash
« Reply #6 on: 31 / January / 2009, 06:31:56 »
Thanks fudgey, I wasn't sure if I just didn't understand the settings for MD  but if you can't help then I am satisfied its not simply a matter of my ignorance.

In fact it does work somewhat  - eg on slow shutter speed the flash fires but a little late. and the script continues. But if I use a slower shutter speed then the script gives an error message and it all crashes.

Perhaps have to go back to a remote MD detector ( PIR or beam) and fire the cam via a relay and shutter release - bummer!
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Offline mgxxx

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Re: Thanks, and G9 motion detection with flash
« Reply #7 on: 31 / January / 2009, 06:36:35 »
sorry, read that as
"In fact it does work somewhat  - eg on slow shutter speed the flash fires but a little late. and the script continues. But if I use a FASTER shutter speed then the script gives an error message and it all crashes."
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Offline whim

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Re: Thanks, and G9 motion detection with flash
« Reply #8 on: 31 / January / 2009, 06:47:38 »
Not sure if fast MD script checks for this internally, but are you positive that the flash is ready/recharged when
it needs to function ?


wim
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Offline Microfunguy

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Re: Thanks, and G9 motion detection with flash
« Reply #9 on: 31 / January / 2009, 07:05:46 »
Quote from: mgxxx on 31 / January / 2009, 06:36:35
on slow shutter speed the flash fires but a little late

I do not believe this  ...... unless you have set flash to second curtain.
See page 151 of the manual.

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fire the cam via a relay and shutter release

You can of course use the USB input to trigger the camera.
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