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Multicam Rig for Events - Step By Step Help Please!!

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Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #40 on: 05 / September / 2017, 18:49:39 »
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Will it affect my synch accuracy if I have USB cables of varying lengths?
AKA, if I use eight 5' cables and eight 3' cables, will my synch time be any less accurate than if I use all 5' cables?
Cable length difference like this will make not affect sync.  Even if you had 2' and 20' cables you would not see a difference.  The extra capacitance might lower the rise time slightly but it would be in the order of a few microseconds.  And of course the extra length will not make much difference to speed of electron flow, which will continue to be pretty close to the speed of light.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #41 on: 05 / September / 2017, 19:06:38 »
Wonderful, thank you :-) That means I'll be able to make a nice clean rig, instead of bundling up feet and feet of cables

Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #42 on: 05 / September / 2017, 20:50:52 »
Wonderful, thank you :-) That means I'll be able to make a nice clean rig, instead of bundling up feet and feet of cables
Using Cat-5/6 (pairs), for multiple-USB's and a separate Cat-5/6 pair for common camera sync, is another option.
Any spare Cat-5/6 (pairs), can also be used/reserved for control functions via the DMX512 standard.
i.e. LED Lighting, Flash, and even Composite Video, HDMI (is best done via a separate cat5/6 cable) etc.
Then use Break-out Boxes at the Main Computer end and the Camera's ends to then connect to the USB Hubs.
I.e. USB-to-Cat5/6 then Cat5/6-to-USB, "to make a nice clean rig", also it makes the multi-cam rig easier to modify/expand,
if necessary at some future time. i.e. adding, if necessary, additional Ferrites, Distributed Filtering etc.
There is a Cat5/6 connecter available for the shield connection or just use a banana style plug/socket for the shield.

Note #1. The USB-1, USB-2 and USB-3 standards do have limits on the USB cable length and the number of downstream HUBs.
Note #2. USB-to-Cat5/6 converters/extenders are a further option to overcome the above limits.
Note #3. USB-to-Cat5/6 converters/extenders will start in USB-1 mode , then change to USB-2 and then USB-3, if available.

H-H
« Last Edit: 06 / September / 2017, 20:43:19 by Hardware_Hacker »

Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #43 on: 05 / September / 2017, 21:00:42 »
That all sounds awesome, and I'll keep a note for future use, but that is waaaay more complicated than I am getting on this first build :-)

Being able to control so much sounds awesome though! :-)


Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #44 on: 06 / September / 2017, 03:05:29 »
And of course the extra length will not make much difference to speed of electron flow, which will continue to be pretty close to the speed of light.

It's a lifetime, for some, since looking at this stuff & this is purely for information and interest only:
https://en.wikipedia.org/wiki/Speed_of_electricity

Quote
The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic wave, not the movement of electrons. Electromagnetic wave propagation is fast and depends on both the permeability and the permittivity of the material. In a vacuum the wave travels at the speed of light and almost that fast in air.

This http://amasci.com/miscon/speed.html has some interesting current flow calculations.


Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #45 on: 06 / September / 2017, 07:54:49 »
And of course the extra length will not make much difference to speed of electron flow, which will continue to be pretty close to the speed of light.

It's a lifetime, for some, since looking at this stuff & this is purely for information and interest only:
https://en.wikipedia.org/wiki/Speed_of_electricity
A life time or not,  I figured somebody would be pedantic about this so I picked my words careful and said "electron flow" and not "speed of an electron".  I'm well aware of the differerence but did not want to complicate the conversation.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #46 on: 06 / September / 2017, 08:23:18 »
A life time or not,  I figured somebody would be pedantic about this so I picked my words careful and said "electron flow" and not "speed of an electron".  I'm well aware of the differerence but did not want to complicate the conversation.

http://www.qrg.northwestern.edu/projects/vss/docs/power/2-whats-electron-flow.html

Quote
Electron flow is what we think of as electrical current.

I figured somebody would be pedantic.

I said:
this is purely for information and interest only

One definition of pedantic is:
excessively concerned with minor details or rules; overscrupulous.

Since my comment was purely for information and interest only your attribution has no basis in my reality.

In any case, electron flow, in a copper cable, is not pretty close to the speed of light.

Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #47 on: 06 / September / 2017, 09:30:03 »
Wonderful, thank you :-) That means I'll be able to make a nice clean rig, instead of bundling up feet and feet of cables
Correct.  The length of any USB compliant cable that you can buy will make no difference in sync precision.
Ported :   A1200    SD940   G10    Powershot N    G16


Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #48 on: 06 / September / 2017, 16:29:49 »
OK, starting to delve into Hugin, as some have suggested. But wow is this a complicated program! I think what I am looking to do is:

1- Take 1 photo each with 13 cameras (I downsized from 16 cameras) of a 3 point reference (such as 3 ping pong balls on a pole).

2- Import photos into a program such as Hugin, and alighn the images (including x-y axis, pitch, yaw, perspective, whatever is needed)

3- Record the previously mentioned alignment actions so that it can be redone on the next set of photos when the reference points are removed and a subject is set in place.

4- Export aligned images as an animated GIF (or just crop and export all photos, and I can make an animated GIF in photoshop)

Any help or hints would be appreciated, and yes I know there are tutorials on their website, but I don't even know what any of this would be called, so I don't know where to start. :-)

Re: Multicam Rig for Events - Step By Step Help Please!!
« Reply #49 on: 06 / September / 2017, 21:16:01 »
OK, starting to delve into Hugin, as some have suggested. But wow is this a complicated program! I think what I am looking to do is:
...........
Any help or hints would be appreciated, and yes I know there are tutorials on their website, but I don't even know what any of this would be called, so I don't know where to start. :-)
A few un-documented things about Hugin, or similar software.
Hugin's main use is for Panorama Photography, so as downloaded that's what Hugin's default settings are optimized for Align_Image_Stack (part of Hugin) can be used as a separate, command line, utility.
And sometimes is used as part of other software such as "Luminance HDR" software.
So as you are attempting to align a series still frames into a mini video, Hugin's settings/defaults then need to be re-optimized for MAXIMIUM OVERLAP of the pairs of cameras.
Starting with the series of common photos of the Ball Target, these settings are reused when attempting to create the final video/Gif file. (Example:- the *.pto file.)
This is "VERY DIFFERENT" to attempting to align a single row or multiple rows of 10%-20% overlapping "Panoramic" photos.
So Align_Image_Stack (A_I_S) now need's to be the primary, fine alignment option, followed by none or some of the other "Optional" CL-programs.
Also Hugins default (course) rotate is +/- 30 degrees, BUT the (course) rotate is achieved, by eye, when setting-up the multi-camera rig array. I use 100 steps of +/- 3 degrees as the new default, or finer, i.e +/- 1 degree, if you use a Canon/CHDK grid as the course in camera alignment option.

An "EYE-Candy" Example.        Edit #1:-
A, commercial, State of the Art "Multi-Cam Rig for Events" by Mark Ruff of Time-Slice-au and "How it Works" here;
http://www.timesplice.com.au/camera-array.html

His "NEW" Multi-Cam Rig  example is here;  http://www.timesplice.com.au/360-camera-array.html

Of some interest; "...The 60 frames are then positionally stabilised, aperture corrected and then turned into 1080 frames.
Next, it is combined with a 2D background and the scene is temporally ramped to provide a smooth and non linear playback..."

"..Some other 360 degree shots..." here;    http://www.timesplice.com.au/360gallery/360blkdress.html
and here;       http://www.timesplice.com.au/3D-camera-array-fashion.html

The video lead in/out effect, can be achieved, with additional Chdk-Movie-Mode Cameras synced/delayed via the
well known/documented "Stills-in Video" method.

The 2d Panoramic background created (separately) with, AutoStich-Demo, Hugin, and lot's more similar types of programs.

The "...turned into 1080 frames..." is a bit more of a chalange, might be able to be done with Pt-Interpolate
which was part of the original version (2000) of Pt-Tools. Or by using the PhotoScan Demo.

"...The camera array is also 3D ready!...60 cameras is equivalent to 59 stereo pairs..."
A_I_S, Hugin and PhotoScan all have options for the "Paring" of cameras.

PT Tools (2000) is Here;       PanoTools.org Wiki,
Pt-Interpolate;    Download example project http://www.panotools.org/dersch/examplesWin.zip

H-H

Edit #2 Added the Attachments.
« Last Edit: 11 / September / 2017, 05:38:51 by Hardware_Hacker »

 

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