I am producing a "live" concert using 3 Sony Z7 cameras. I am renting an Edirol V8 mixer to record it to a VTR Sony M15. Do I need to get some kind of external TBC? or the 3 Sonys Z7 are going to work well?

They will work perfectly, but the Z7 does not allow any form of time based synching, so you'll need to use a clapper or some other means to get a common 'in-point' for the three camera's. In Final Cut Por, theres multicam editing, so if you use that, it should be a piece of cake.
My advice: let the audio on all the camera's record also, just as a reference. You never know... and don't forget to set the image format and size to he same size on the three camera's, otherwise multicam editing won't work.

Pablo,
For switching live, The Editrol mixer should work as it has built in frame synchronizers so you don't need any TBCs. The mixer will sync your cameras for you. It only allows composite or S-Video inputs, no firewire. From Editrol's website it looks as if the V8 is really intended for presentation switching in churches, clubs etc. The live switch may not be as clean as you expect. In the specs they list "seemless switching" available in "presentation mode" The more professional LVS400 lists "yes" in that category. I would test it prior to the event.
The other option is to tape iso as Luc suggests, using a clapper to sync the cameras or use the Z7's timecode sync function to match TC on all cameras. Finally you could do both, recording iso in camera and live switching. The iso tapes could save a bad switch. Best of luck.

Lee

Thank you Luc and Lee
I will follow the advice. I will also check the other mixer Lee suggests. Thank you very much for your input. Regards from Poland

Are you aware that you can jam sync the camera's together via the firewire ports.
This is in the manual and will set the timecode clocks identical on all three cameras.
I have used this for several conferences and it will make multicamera editing easy if you also set the timecode to free run (we used time of day as reference)

Or you could sync using PluralEyes: PluralEyes (http://www.singularsoftware.com/autosync/)

It doesn't need timecode, clappers, etc.

Bruce

Thank you for the advice. I'll check the manual once again to try to understand exactly what you mean. When you write about "easier editing", it means that you edit your material after the shooting, am I right?. I am trying to avoid that step and mix the three cameras as if I were shooting live. That's why I am renting the Edirol V8 and recording the mixed video straight to a VTR Sony M15. All I want to do after is to add a few titles titles. I use Premier Pro on a PC.
Thank you.

Thanks for your help. Is PluralEyes for PremierPro as well?
What is the cost?
I just checked the link you sent me and watched the clip, it doesn't make me feel very confident. I guess there is no use for it if I want to do a live show, is there?
Thanks.

I would do this job as you say by mixing the three camera sources together to a master via the vision mixer.

I would also record each camera to its own tape deck or CF unit as isolated sources so you have cover for any mistakes in the live mix.

If you jam sync all three timecode readers as mentioned via firewire and run the timecode as time of day free run you will then have the same reference on each camera, if you can also feed each camera or at least have the cam mic recorded you will also have a sound sync reference point.

Most of the modern mixers will allow re-syncing of any composite source so you should not need a video reference to each camera.

If you need HD it will get a bit more complicated but I am sure it will not be a huge problem, just bear in mind that the Z7's have HDMI and the S270 has SDI output so composite will be the easiest way to get all three to the mixer.

If your master record deck is similar to the Z7/S270's you should be able to jam sync it too so if you need to edit you will end up with a master mix track and three iso cameras all with the same timecode reference points regardless of when the go into record.

P.S dont know how much you are renting the edirol for but I have a panasonic W30 mixer for sale at £350 if you are interested, it will allow you to re-sync all three cameras and do the mixing part for you, it also has basic effects and is a well known live mixer.

Pablo, how is the V8 to work with?

Does it have fast response when pushing the buttons from one cam to the next, and can you switch back and forth multiple times within one second?

How is the image quality? Can it even remotelly produce a picture resembling a SDI signal?

I had the "pleasure" of handling a DataVideo 500 yesterday. And plain out it was probably the worst piece of electronic I've ever put my hands on. The response was so slow that I could only switch once a second. Image quality looked as if we were shoting with webcams.