Nevertheless I am unsure how to go on with my camera rig.
What would you propose? Should I:
2 - wait a little because the things you discuss here will maybe provide a solution that makes special hardware unnecessary?
Martin,
About Your "50-camera" rig and setup
Camera Alignment.
Do you have a camera alignment procedure, such as calibration target, at the cameras focal point.
i.e. PingPong, Golf or Tenis balls mounted on a fishing line.
Do you have a camera software calibration procedure.
i.e. Hugin's latest "Align Image Stack" or some thing similar, that provides for sub-pixel image alignments.
Rig & Setup
1/ A Multi-Camera sync cable has no length limits, but a longer sync cable is more likley
to have RF and Noise pickup problems that will affect the camera sync. (i.e. use RF supression Ferrites)
2/ If the Multi-Camera sync cable is a also a "USB" cable there is a, USB, length limit of about 5 meters.
There is also a limit of about three USB-Hubs in series.
3/ So if you are using 10 port USB-Hubs you would need 5 NoteBooks. And if you look at photos of other Multi-Cam rigs they usualy have quite a few notebooks as part of the rigs.
4/ Some Multi-Port Hubs are easy to modify in regard to switching the 5 volt power supply (syncing) and then fully "Discharge" the 5 volt supply via a suitable termination resistor.
5/ However you have to be aware of a another potential problem, that in a "Standard" Sync USB cable there is no "Discharge" path, except for the camera's internal non linear circuits.
This has been a subject in several previous posts and dosn't appear to be a problem with twined cameras but could be major problem with your rig that has a combination of long USB cables and 50 cameras.
6/ An Idea I am currently working on (for a Multi-Cam rig) is boot the NoteBooks, or Oblsete computers, from a CdRom all the windows software then runs in RAM. This has been tested on, and works relaibly with, Xp and windows-Blue.
7/ While this may, at first, seem complicated in practice its not as there are various example projects which you can download and easily customise to your needs.
8/ There are several advantages to this aproach with multi-cam rigs such as reliability, repeatability, and dependability, as each NoteBook is runing the same software so project management, software modification and up-grades are all very easy.
9/ Also it is posible to have an absolute software path to each camera (via "Merging") where by each camera is customised and allocaded it's own ID which also makes camera management and image downloading much easier.
10/ Normaly the Canon cameras are "Installed" which is a "Random" process which is then combined with many other "Random" windows processes. Also windows allocates a "Weight" to the "Instalation" of the cameras so this mess/combination can easily become un-stable and un-reliable.
11/ Another Idea I am working on is a new faster (x10,000) and more flexible method for syncing a Multi-Cam rig. It is interesting to note that windows-Blue, a "Preview" is free to download, and has built-in support for this concept.
12/ A customised CHDK build can improve the overall performance of both PtpCamGui and ChdkPtp so this is a option to save image procesing time.
H-H
Happy Hacking
Continued ...
