Building a mult-camera rig - page 18 - Hotwire! Hardware Mods, Accessories and Insights - CHDK Forum

Building a mult-camera rig

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Thank you, reyalp  ;)

Hi All

Today we took the rig outside in order to test it with people on the street.

Basically the system works, few modification was needed

1. Remove AC power next to USB cables (we put 220v cable around the rig to power the usb hubs & 4.3 volt power supplies for dummy batteries)

2. Turn on cameras before powering up the USB hubs

3. Adding external lighting - but seems to be not enough (still long shutter)

one important conclusion - we must control on camera setting ,  AUTO Mode isnt good enough

How can we control on camera setting from PC ? or via script ?

  • Shutter speed
  • ISO
  • Aperture


I would appreciate your assistance




 

The photography basics don't change when you use a multi camera setup. You do not need extra light for extra cameras. Try setting the ISO in the Canon menu to at least 400 for example. Or put the cameras into "sports" mode to get the fastest shutter speed.   

Otherwise, you can use a script to read the scene illumination and set as high an ISO value as necessary to keep the shutter speed above your desired minimum value.
Ported :   A1200    SD940   G10    Powershot N    G16

Thanks for the quick reply


Will try to find the sweet point for shooting.

Which command to use for setting shutter speed / iso / aperture ? I prefer to control it from remote


regards



Which command to use for setting shutter speed / iso / aperture ? I prefer to control it from remote
The "sweet point" will change with scene illumination

I believe reyalp set the shoot() command in his multicam script to accept exposure parameters.  Take a look at his source / docs ?   I'm travelling now and can't do so easily from my POS mobile phone
Ported :   A1200    SD940   G10    Powershot N    G16

*

Offline reyalp

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  • 11992
Which command to use for setting shutter speed / iso / aperture ? I prefer to control it from remote
The "sweet point" will change with scene illumination

I believe reyalp set the shoot() command in his multicam script to accept exposure parameters.  Take a look at his source / docs ?   I'm travelling now and can't do so easily from my POS mobile phone
The multicam 'shoot' function does not, but testshots does. Assuming you are using a script like multicam or bcam, you just need to send the 'call' command with lua script to set the desired parameters. See http://chdk.wikia.com/wiki/CHDK_Scripting_Cross_Reference_Page

If you want to be able to enter more friendly units, you can refer to the code for the shoot cli command

edit:
One important thing to remember if you are setting exposure parameters using lua functions is that in general, script overrides are only applied while the script that set them is running. So if you are working with a single camera and do something like this:
Code: [Select]
=set_tv96_direct(1024)
=shoot()
The exposure will not actually be set, because each = command runs as a new script and overrides are cleared in between. Instead, you should use something like:
Code: [Select]
=set_tv96_direct(1024) shoot()


In multicam, the script is started when you use mc:start() and runs until you send the exit command, so you can use
Code: [Select]
!mc:cmdwait('call set_tv96_direct(1024)')
followed by the calls to shoot.

edit:
Corrected typo
« Last Edit: 03 / September / 2014, 16:20:25 by reyalp »
Don't forget what the H stands for.

thx.

When I run BcamRem.lua script on camera, is it still possible to use  >
Code: [Select]
!mc:cmdwait('call set_tv96_direct(1024)')

*

Offline reyalp

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  • 11992
It doesn't appear to be present in the last copy of bcam I download. You can probably just copy the cmds.call code from chdkptp multicam after the other cmds.* lines in bcam.

cmds.pcall in multicam.lua does the same thing, except that if there are errors in the lua code, they will be caught instead of ending the script. However, you don't use some functions like sleep and keyboard related calls inside pcall.
Don't forget what the H stands for.


Shall I copy it to bcamhost (running on camera ) or to bcamRmote(running on PC)


*

Offline reyalp

  • ******
  • 11992
Shall I copy it to bcamhost (running on camera ) or to bcamRmote(running on PC)
I think you have that backwards, in the zip I have bcamRem.lua is camera side code.

The cmds.call etc are camera side code, so they would go in that file. You should see cmds.rec, cmds.play etc in the file. Paste the code for cmds.call below the end of one of those.
Don't forget what the H stands for.

 

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