Shooting with multiple EX Cams

[Tony LeHoven]

Had the opportunity to run a 5 camera shoot. 4 EX1s and an EX3. Set everything to fire off of one remote . . .the fact that when you power cameras down remote functionality goes away was a pain in the ass. Had all the clocks set to 00:00:00, started them with one remote. Used the remote to start record simultaneously. Shot sync marks with all the cameras.

Conclusion: It doesn't work. At the sync mark all the timecodes are different. Close but different. The start times are varied in code also as well as the physical time. Sounded like a good idea that should work but it doesn't. Luckily I had BB ref going into EX3 and was synced with the audio guy pulling a 12 channel mix for edit. AND shot the sync markers.

-Tony

[Khoi Pham]

Are they all on the same type of timecode? free run df or ndf?

[Tony LeHoven]

I set the time code based on the camera clock, which is drop frame.
-T

[Ted OMalley]

I thought camera clock meant the camera's internal clock - as in 17:11:08 (5:11:08pm)

[Tony LeHoven]

The camera clock writes what looks like drop frame free run time code.
-Tony

[Jason Davenport]

You will never have true locked time code, unless they are all genlocked to a source. Even TC to TC via BNC will miss eventually, unless genlocked.

[Peter Kraft]

Correct. I doubt that the EX1 has a Genlock In and can be slaved to a TC source.

[Jason Davenport]

Yep, EX-3. Not 1

[Peter Kraft]

Originally Posted by Tony LeHoven

The camera clock writes what looks like drop frame free run time code.

And that TC is as precise as it is generated by a xtal driven electronic circuit.
The better (more precise) the xtal, the more precise the TC. Deviation from
ideal output is measured in ppm (parts per million) and shows the quality of
the xtal.
I doubt if Sony would publish the specs of its TC generator.

[Tony LeHoven]

Yeah, yeah the EX3 was totally genlocked. I just thought that firing everything from the remote would give me 5 cameras with the same timecode. I mean it seems like it should work . . . push the button and everything starts at the same time, clocks and roll. My point is that it doesn't. Maybe it shouldn't work but with today's new technology, it doesn't hurt to try.

Thanks for your input,
Tony

[Peter Kraft]

What is the moral of Tony's story?

Take only EX3s and genlock them ;-)


My poor man's solution: I distribute the same sound to each and every camera so that it can
record picture and that sync sound, preferrably the out signal from the PA's mixing console -
and I edit according to the sound. Every cheap camera can contribute to that scheme.

P.

[Marc Myers]

An alternative is to use a switcher. I have four EX1s purchased for use in a camera chain before there was an EX3. I'm getting very decent results. I try to keep one camera wide all the time and I record to the SxS card on that camera just in case there's a mistake that needs covering later. Most difficult for me is painting the cameras. I use auto-white and then have to tweak.

[Ted OMalley]

Originally Posted by Marc Myers

An alternative is to use a switcher. I have four EX1s purchased for use in a camera chain before there was an EX3. I'm getting very decent results. I try to keep one camera wide all the time and I record to the SxS card on that camera just in case there's a mistake that needs covering later. Most difficult for me is painting the cameras. I use auto-white and then have to tweak.

Marc,

Why would that be preferable to trying to pull a good white balance with each camera on a common subject prior to the shoot and keeping it all manual?

I ask this because I recently did a shoot where I pulled a good white balance in a low-light environment and without thinking set the camera to Auto WB. Over a few seconds (without me noticing), everything slid away from white and all my whites ended up cream-colored.

I intend to use Auto WB exremely selectively, if at all.

[Marc Myers]

In practice, that's what I do. The similarity among whites with EX1s is VERY good when you white balance manually. That said, if you have one or more cameras with different circumstances, a camera shooting near a window you can't shutter for example, tweaking is still required. And when I have to tweak I really wish I had a CCU.

[David Heath]

Originally Posted by Peter Kraft

And that TC is as precise as it is generated by a xtal driven electronic circuit.
The better (more precise) the xtal, the more precise the TC.

It's important to realise that the crystal primarily controls the frame rate of the camera, and the TC is directly derived from that - one frame = one TC reference.

Which is why you can't simply feed one cameras TC into another camera without genlock, the TC frames would "slip" relative to the actual video frames.

Even if the absolute TC figures were different, genlocking cameras will ensure that the offset remains constant throughout any recording.