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-   -   Equipment for mult-camera shooting??? (https://www.dvinfo.net/forum/open-dv-discussion/8560-equipment-mult-camera-shooting.html)

Wil Spencer April 11th, 2003 10:01 AM

Equipment for mult-camera shooting???
 
What equipment are you using to shoot with multiple cameras in the field? (Or in a low-budget studio) Six years ago I purchased several analog genlockable cameras and cabled them up to an analog video mixer. But lately, I don't see the genlock capability on any digital video cameras in the $2K-$4K range. Several digital switches have appeared but, the cameras in the $2k-$4K range don't have cables for driving video over 20- 40- or 60- feet.

Several of the newest switches accept IEEE 1394. But, I think the spec on 1394 calls for maximum cable length of 10 feet or so (I may be wrong on that???).

I have seen several posts for editing independent camera video in post-production. Is that the best way to go?

Thanks,
Wil

Wil Spencer April 11th, 2003 04:22 PM

Points not address in other threads
 
Many of you have seen some discussion on multi-camera shooting on other threads. But, I could not find answers to the following specific questions:
(1) If you use an analog switch, how do you genlock the multiple cameras?
(2) How do you send video (from a camera like the XL1s or GL2) over a 60ft cable back to the switch?
(3) If you use independent cameras (not connected to a switch during the shoot) how do you coordinate camera operators so that you always have good video on at least one camera and so that pans or zooms are going in the same direction for consistent cut-overs in post-production.

Thanks,
Wil

Garret Ambrosio April 11th, 2003 04:38 PM

I can probably answer number two, they have 1394 repeaters that can relay the signal to an additonal 100' . I only been able to find these however on the net. Compusa have reapeaters but I don't thinkt hey will give you the range you want.

Jeff Donald April 11th, 2003 07:40 PM

Most people mix it in post in their NLE. The few people (I know) who switch it live are using older configurations. New mini DV cameras just don't have provisions for coax cables and long runs, etc.

James Emory April 11th, 2003 10:46 PM

Multi-camera DV projects
 
Will,
Howdy. Well, I have done just what your describing quite a few times for live broadcast, IMAG and live to tape projects. I have gone the route of using Y/C to 2 BNC Y-splitters that seperate the Y and C carriers into two BNC cables. I then connect these to 200 ft a/v snakes that have two true 75 ohm broadcast BNC returns back to the truck. Then, at the truck I rejoin them with another splitter directly into the switcher's Y/C connections. I have to say that I also use Kramer 401c DAs that happen to maintain signal strength but is only used to split the signal again to provide feeds for the source monitors for each camera. The DAs are not necessary but sure don't hurt. I have gotten nothing less than crisp, clean results every time. I think the furthest you might want to go before experiencing signal loss would be 300 ft. I always ISO each camera for backup and of course record the mix in the truck. I also always get a head and tail slate in case one or more cameras temporarily stop recording and break sync. I think gen locking cameras is a time saver but not really necessary if you get a good visual sync reference. It's really easy to slip the tracks in post if you have to manually do it without a good sync reference.

Scroll down on this link to view the cables
http://community.webtv.net/JEFProduc...PRODUCTIONUNIT

If you use multiple off-line cameras for later cutting together make sure to get a head and tail slate reference. The only way to get great unduplicated shots is to have some damn good operators that shoot certain zones and try to have a wide locked down shot to go to if there are duplicated shots. In short they will be improvising!!

Check out this software for off-line multi-cam cutting

www.unitedmediainc.com

Jeff Donald April 12th, 2003 02:17 PM

James, are you switching live or recording the feeds to separate tapes?

James Emory April 12th, 2003 03:02 PM

On & Off-line switching
 
I was describing two different scenerios for Will. I switch the cameras live to tape and ISO (in camera) each camera for backup and/or fixes in post. The other was for off-line multi-camera where it's a free for all. This is a pay now or pay later situation. Pay more up front for live mixing, quicker turnaround and minor fixes OR pay (sometimes much more) later for hours if not days cutting it all together and hoping the camera ops got adequate coverage.

Jeff Donald April 12th, 2003 03:10 PM

If Will has an analog mixer, he would not be able to switch live without genlockable cameras. If he had a switcher/digital frame sync he could switch live.

James Emory April 12th, 2003 03:17 PM

Switcher
 
Ok. I think I see what you're asking now. If the switcher does not have internal sync ability, then he will have to have external TBCs maintaining sync to switch them.

Wil Spencer April 12th, 2003 03:34 PM

Looking at two variations of switches
 
Thanks James for your valuable advice. I own an old analog video switch that works with my (now outdated) genlockable cameras. But, I've been looking at two versions of the new digital switches. One, as you described, digitizes the analog inputs for mixing (and video synchronization) so no genlock in needed. That one should work well with the setup you explained. The other accepts IEEE 1394 inputs. For that one I could use the line drivers suggested by Garret. In a quick search I found several that will drive up to 32ft and can be used in series up to several hundred feet. I'd like to find one that can drive 100ft by itself.

I agree with James if you decide to mix several independently operated cameras during NLE you may get to places where you don't have anything really good on any camera (e.g. all cameras on the move to new positions at the same time!).

Thanks to all!
Wil

Ron Johnson April 12th, 2003 05:57 PM

http://www.hosatech.com/digital_products_index.html#FXT-401

Above is a link for a 50 meter (165 foot) firewire extension product.


RJ

Rick Pearson April 8th, 2005 07:59 AM

Genlock
 
I own a km-1200 analogue mixer and recently took it to one of my station's engineers this is what he had to say:

"This mixer accepts 5 cameras, but only four of them need to be genlockable. You can use any non-genlockable camera at input #5 which is also your genlock reference. So by placing a non genlockable camera such as a XL1s, or PD150 as your genlock reference you can tell the other cameras to sync to the XL1s/PD150."

Obviously this applies to any analogue mixer that doesn't generate it's own frame sync/genlock. You can use any camera as a source for genlock that your other genlockable cameras will sync to.

Once all of the cameras are cabled into the switcher, you will also have to manually adjust each of the cameras to match color tint, as well as vertical and horizontal alignment so that there are no misaligned shots between cameras. Once this is done; start shooting.

Bobby Abernathy April 8th, 2005 01:52 PM

Not sure if you've ever checked out Newtek's Video Toaster, but it's a great digital switcher. No need for genlockable cameras or external TBCs, it syncs all inputs automatically. Its input interface, the SX-8, will accept composite, Y/C and component inputs, plus you can have firewire devices on the switcher using regular PCI firewire cards, or SDI inputs using an additional daughter card.

Glenn Chan April 9th, 2005 12:08 AM

Quote:

(1) If you use an analog switch, how do you genlock the multiple cameras?
There are some mixers with two TBCs built-in. An example would be the discontinued Videonics MX-1, which retailed for $1000. A better similar mixer would be a modified Panasonic MX-50 (no lag on cuts).

The Video Toaster is also apparently very good, but more expensive of course.

Quote:

(2) How do you send video (from a camera like the XL1s or GL2) over a 60ft cable back to the switch?
As James points out you can get an adapter to two BNC cables. Some companies do sell S-video cables but they are just expensive and not any better than the adapter/2BNC method. You may also be able to use co-axial cable, which I think is 75ohm too?

What you don't want the cable to do is to attenuate/weaken high frequencies. Cables at a certain capacitance (which is what 75 ohms refers to; not the actual resistance in the cable) will attenuate the wrong high frequencies.

That's as far as I know.

Quote:

(3) If you use independent cameras (not connected to a switch during the shoot) how do you coordinate camera operators so that you always have good video on at least one camera and so that pans or zooms are going in the same direction for consistent cut-overs in post-production.
A- Have a good plan and camerapeople who know the plan.
B- Have good camerapeople with good tripods and know how to use them, as well as a decent sense of composition and know about over/underscan. They should know not to get shots that are similar to others. Angles cut together better when they are not too similar or extremely different (this avoids jump cuts).
C- You need an intercom or walkie talkies (more or less 1-way communication while shooting). Get isolating headphones... i.e. full size closed headphones.
The director should should be heard clearly.
D- Hook up all the cameras to monitors and have a director direct them so you get stuff that cuts well in post.


4- Last time I tried editing something in post it was painful. But it will go easier if you have:
-A camera on stage shot... which you can always safely cut to (as long as heads/people don't block it; get a tall tripod).
-Cutaways. Shots of the audience and stuff like that. You can edit these in out of context and they will work.
-If the camerapeople shoot with slow and smooth camera movements all the time, it should be easy to cut in and out of their shots without much problem. You absolutely need a good tripod head for this (i.e. fluid head that supports the right weight). You also need good zoom controls.
-Panning shots that go in opposite directions don't cut well.
-In post production, do not look at every camera angle and carefully analyze which is best. Just go through and make semi-arbitrary cuts. Then go through, see what doesn't work, and fine tune.
-Have each camera shoot certain types of shots (i.e. one cam shoots close-ups). So in post, when you think you would like that kind of shot, you can just cut to that shot and it should be there most of the time.

Vegas with the Excalibur tool seems like a great way of editing multicam.

5- Editing live versus editing in post:

Live:
-fastest
-if your team is inexperienced, editing live isn't that great because you will have mistakes.
-Needs a little more setup during production day and a video mixer + record deck.

Edit in post:
-Can take a long time.
-May not have the shots you need?

Ed Liew April 9th, 2005 12:04 PM

this is what i use... panasonic mx70 and also the panasonic ave-5 for mcp work. edirol v1 is a good unit which i'm thinking of getting. you can find one in ebay for less then 700.00.

as for cabling, my exprience is, quality cable does help. i'm using the belden 6c cable. 100meter, no problem. i have tested the canari 2a1v cable of 100 meter length, no problem with picture quality - result from my old hitachi vector and waveform monitor. canari cable is only 3c, much lighter and i can use the audio cable for intercom. i will be getting the cable middle of this month. con, very pricey.

also, i would agree with glenn, editing a not well plan multi camera work is tough. for professional camera and deck, we use the timecode free run setting and sync the timecode of all the recording equipments. with this, you'll less problem during post. for me i would prefer to mixing the shot then to record individually. but sometime thing just don't come our way. i'm in the mist of planning a six cameras work in june. its going to be in a water theme park with events happening in different location. so, lots of pre work before the real thing.

good luck.

ed


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