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Sync Multi Cameras - 3d Modeling

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Sync Multi Cameras - 3d Modeling
« on: 13 / October / 2012, 13:27:19 »
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I'm setting up a 24 - 30 camera rig for 3d modeling.  I'm using either 123d catch, or PhotoScan to stitch and scan the pictures.  I'm pretty familiar with both apps.  I have a couple questions before I go into full production of building the camera rig:

1. I'm using SDM currently, and was wondering if the new USB Remote code http://chdk.wikia.com/wiki/USB_Shutter_Remote makes CHDK sync as good or better then SDM, in regards to accuracy, easy of use, and or functionality?

2. I bought three SD800 IS cameras and have been testing on them before buying more.  Does anyone have a preference between SD800 IS and the SD1300 IS ?

3. Can you use an IS camera even if the CHDK supported camera is a non IS?  For example: SD800 supported, but can I use SD800IS?

4. I have found a couple good threads and site about sync, but nothing with detailed info about set up and process.  Does any one have a great tutorial or similar site or thread about multi camera sync (more then 2 camera)?

Thanks in advance.

-David

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Offline nafraf

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Re: Sync Multi Cameras - 3d Modeling
« Reply #1 on: 13 / October / 2012, 13:56:15 »
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3. Can you use an IS camera even if the CHDK supported camera is a non IS?  For example: SD800 supported, but can I use SD800IS?
Both models are the same camera: http://chdk.wikia.com/wiki/SD800
In CHDK wikia page, some times it is referenced as SD800, sometimes as SD8100

Re: Sync Multi Cameras - 3d Modeling
« Reply #2 on: 13 / October / 2012, 14:05:44 »
wondering if the new USB Remote code http://chdk.wikia.com/wiki/USB_Shutter_Remote makes CHDK sync as good or better then SDM

It is impossible to be better.

In addition, with SDM a synch error of just 1/2500 sec after 50 minutes of continuous shooting can be achieved.

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2. I bought three SD800 IS cameras and have been testing on them before buying more.  Does anyone have a preference between SD800 IS and the SD1300 IS ?


Just one hour ago we tested the inexpensive A810.

The median synch error is just 1/8400 sec !

That is extremely good.


David

Re: Sync Multi Cameras - 3d Modeling
« Reply #3 on: 13 / October / 2012, 14:06:17 »
1. I'm using SDM currently, and was wondering if the new USB Remote code http://chdk.wikia.com/wiki/USB_Shutter_Remote makes CHDK sync as good or better then SDM, in regards to accuracy, easy of use, and or functionality?
AFAIK,  SDM uses a slightly modified version of the old USB remote code from the obsolete CHDK 1.0 trunk.   That old CHDK version mostly worked but was very hard to configure.    The new CHDK USB remote code was made modular to allow easy extensions and a easier to understand UI.

The actual "sync" mechanism in SDM and CHDK is the same - they both cause the camera to wait just before the shutter is released for the USB remote voltage to go away.  Sync performance will be identical.

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4. I have found a couple good threads and site about sync, but nothing with detailed info about set up and process.  Does any one have a great tutorial or similar site or thread about multi camera sync (more then 2 camera)?
The only real difference when you go beyond two cameras is the electrical requirements for the sync circuit.  I believe the folks at gentles.com have worked that out for you if you purchase their kit.

The other difference is the amount of work it takes to setup all those cameras.  There have been threads about using a common cchdk.cfg (of cchdk2.cfg) file and about using a script to setup the Canon features.   Nothing perfect unfortunately.
Ported :   A1200    SD940   G10    Powershot N    G16


Re: Sync Multi Cameras - 3d Modeling
« Reply #4 on: 13 / October / 2012, 14:15:46 »
The actual "sync" mechanism in SDM and CHDK is the same

The latest version, 1.86, has not yet been released.
We are trying to get it finished.
Lack of interest in doing tests by selfish users does not help.


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Sync performance will be identical.


I am not aware of any CHDK users doing the proper, scientific  test with a CRT to measure synch.

Re: Sync Multi Cameras - 3d Modeling
« Reply #5 on: 13 / October / 2012, 14:24:17 »
The latest version, 1.86, has not yet been released.
I'll eagerly await version 1.86 to see if you have found a way to improve on the identical 

"BL wait_until_remote_button_is_released"

mechanism used in all existing CHDK and SDM releases to date.
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline nafraf

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Re: Sync Multi Cameras - 3d Modeling
« Reply #6 on: 13 / October / 2012, 14:28:25 »
I am not aware of any CHDK users doing the proper, scientific  test with a CRT to measure synch.
How should be done the proper test?
Thanks

Re: Sync Multi Cameras - 3d Modeling
« Reply #7 on: 13 / October / 2012, 14:34:44 »
How should be done the proper test?
Thanks
Take a look at this :
http://stereo.jpn.org/eng/sdm/crt_synch.htm

video for the ADD generation :P
SDM Fast Time-laps synch test
Ported :   A1200    SD940   G10    Powershot N    G16


Re: Sync Multi Cameras - 3d Modeling
« Reply #8 on: 13 / October / 2012, 16:51:19 »
Thanks for all the great info! 

I forgot to mention that CHDK and SDM are both very cool.  Thanks devs, you guys rock!

Nafraf - good to know. :)

Microfunguy - those sync times are amazing.  I look forward to 1.86.  I'm happy to try it out on my SD800s

waterwingz - great info, thanks for the details.  Also, nice movie.

Here's another question:

5. I ordered the gentles system last week.  It should arrive in a couple days.  In the mean time I'm trying the method of plugging and unpluggin the USB cable to trigger the shutter.  It's not working with CHDK, do you have any suggestions?

6. should I be using CHDK 1.1 or 1.2? 

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Offline reyalp

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Re: Sync Multi Cameras - 3d Modeling
« Reply #9 on: 13 / October / 2012, 17:13:00 »
6. should I be using CHDK 1.1 or 1.2? 
If you don't need any new features introduced in 1.2, I'd suggest sticking with 1.1 for now. 1.1 does include the new remote code.
Don't forget what the H stands for.

 

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