Canan A470 - script for taking pictures at same time as strobe lights - Script Writing - CHDK Forum

Canan A470 - script for taking pictures at same time as strobe lights

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hey....

so basically i need some help with scripts, im doing a project in uni using photogrammetry on a vibrating turbine blade and so am using CHDK to hopefully be able to take pictures at the same frequency as the strobe lights.   

can anyone recommend a script that would so this job? i dont understand computer language much so any help would be very greatly appreciated...

Thanks Rachel
 ???

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Offline reyalp

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Re: Canan A470 - script for taking pictures at same time as strobe lights
« Reply #1 on: 06 / March / 2010, 18:46:35 »
You probably need to give a bit more information about your setup and goals to get useful advice. How is the strobe controlled, how many exposures do you want this to run for, is there other ambient light aside from the strobe, is building hardware to trigger the camera or strobe and option, etc.

In general, in this kind of a setup the strobe is doing the exposure, so you don't really need exact synchronization, you just need to make sure the shutter is open at that time it fires.

The camera can only physically take stills at around 2FPS (at best), so if you are planning on capturing at a higher frequency you'll have to do something else.
Don't forget what the H stands for.

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Offline fudgey

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Re: Canan A470 - script for taking pictures at same time as strobe lights
« Reply #2 on: 07 / March / 2010, 03:33:15 »
The camera can only physically take stills at around 2FPS (at best), so if you are planning on capturing at a higher frequency you'll have to do something else.

...such as an externally triggered array of multiple cameras.

Re: Canan A470 - script for taking pictures at same time as strobe lights
« Reply #3 on: 07 / March / 2010, 07:08:22 »
my goal is to capture the modal frequencies of the turbine blade using strobes and reflective targets so i can reference the photos taken from an array of 4 cameras at different angles around the blade and use photogrammetry to make 3D models...

the strobe is going to be the only light source and i want it to run for around 10 exposures....yes i am building remote triggers using usb a from laptop to mini usb cable into the camera...so i basically want a script that will enable me to press the trigger button or hold it down and the shutter will be triggered to keep on taking photos until i press the trigger again or realease it...  im not using a very high freq, its not specified yet though, but the strobes can be set to any frequency..

the cameras i am using are Canon A470's

how do i make sure the shutter stays open for when the strobes is firing?

thanks 


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Offline fudgey

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Re: Canan A470 - script for taking pictures at same time as strobe lights
« Reply #4 on: 07 / March / 2010, 09:01:17 »
how do i make sure the shutter stays open for when the strobes is firing?

Use external trigger for the strobes instead of a fixed frequency. Then use a secondary external trigger for the cameras, set to fire the cameras slightly before the strobe trigger. Use long enough exposure time on the cameras to reliably catch the strobes. Make sure it's dark enough between strobes so that all you'll see in the photos is the strobe illuminated blade. A strobe period of a few seconds should be doable this way.

You'll want to use the synced remote mode in CHDK.

I didn't know you could control USB supply voltage on any laptop, though (essentially what the CHDK USB remote requires -- it's not really USB, it just uses the USB port on the camera).

Re: Canan A470 - script for taking pictures at same time as strobe lights
« Reply #5 on: 07 / March / 2010, 10:57:20 »
You do not need a script.

Obtain a gentSTEREO Pro remote.
You can control two cameras with this device.

You will also need the gentSTEREO-REPEAT.
The latter will enable you to attach up to a total of twelve cameras.

The flash-synch output will control your strobes and be synchronised with the camera shutters.
The shutters will typically be synchronised to 1/5000 sec.

In SDM SPORTS mode using this controller, you can shoot continuously at 1.3 fps ... assuming that your strobes can recharge fast enough.

Read the manual here.

David

 

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