Multi-Flash over distance

[Yossa]

Hi,
Not really a photography question, but more a question on the limits of multi-flash systems.

As a background to this, I'm trying to set off a 5 seperate flash bulbs in the field of view of 5 seperate cameras (CCTV cameras) so that I can synch the footage up at a later date (a cheap version of a digital clapper board). None of the cameras fields of view overlap, and they can be up to 200ft away from each other.

I'm assuming I can just short out a synch cable and they'll all go off?
What are the maximum lengths of synch cable available?
What type of cost would I be looking at for long lengths of synch cable and 5 flash bulbs?
Any other ideas (wireless?)?

As you can probably tell, I'm pretty new to this.
Thanks in advance for any help,

Yossa

 

[Hacker]

I'm not really sure why you would want to do this. If I'm reading this correctly you need the flashguns for CCTV usage but it is unlikely that you would get usable images due to the brief flash duration times and the fact that the CCTV camera is unlikely to be quick enough to adjust it's aperture to take into account the flash.

If you wish to light subjects for this why not use continuous lighting (floods, spots etc) maybe coupled to an IR or MD sensor.

However, back to your original question. I have no idea what the maximum lengths of synch cable effectiveness are but I doubt it will be 1000 feet. I have no idea what the cost of this cable would be.

With regard to wireless, yes there are are a few products on the market which will fire a flash this way, I think they usually cost around the £200 - £300 per unit.

Hope this helps and I'm fascinated as to what you want this set up for!

 

[Yossa]

Hi,
Cheers for the reply. I was a bit vague with what I'm doing.
The flash isn't for illumination of a subject, it's for synchronisation of footage.
We'll have 5 CCTV cameras pointing at different areas. We'll be capturing the footage onto recorders and using a timecode generator to make sure that the footage can all be synch'd together (they must start and end at the same places). However, if for some reason the timecode becomes corrupt, we've no way of making sure the footage is in sync. Broadcast industry would use a clapper board to sync all the streams together, but our footage is not overlapping (i.e. the cameras are looking at different areas), therefore I need a visual point across all 5 cameras that shows me a sync point (small flash of light). I was thinking of using a string of camera flashes (1 bulb per camera field of view) and setting them off at the same time so I have a fall back point if I need to re-synch the footage later.
The other option is to walk to each camera with a digital clapperboard (timecode display), but they cost about £1,500 each and it takes time.

Hope this clears up what I'm trying to do and thanks for any advice.

 

[Hacker]

I think I know what you're talking about.

Will this be at night time or during daylight hours? I'm just trying to think of other ways you can synch them together, if you have sound on your cameras you could use a firework or speak to a friendly farmer and borrow a crop scarer. If you don't have sound using flash guns will work out expensive, particularly if start adding on wireless. Nikon flash guns have a built in wireless functionality for their Creative Lighting System but I am not sure if they will extend to that range and you would need a Nikon Camera or controller to act as the master and the others would be slaves.

If you are shooting at night time again you could use a firework as visual reference but it might scare off any subjects you are trying to shoot.

Interesting challenge though, must get my thinking cap on.

 

[Yossa]

Cheers for the reply.
All internal, all CCTV (i.e. no sound). Also, the flash must be bright enough to pick up on the CCTV, but not bright enough to cause distruption to the surrounding area (that's why I was looking at camera flashes). I suppose another option would be to use simple LED lighting linked to 12V and a switch. Turning on the switch turns on the lights. The only problem would be the speed of response of the lights. I'm swaying towards a digital clapper board at the moment as this method looks like it might be too difficult to implement.
Cheers.