Anybody ever encountered a problem like this? I know that Panasonic camcorders like the DVX and HVX are cursed with unreliable gain controls, but crimany, I just finished a shoot with a DVX100b that was just terrible. Gain settings would shift as much as 10dB, mostly down fortunately, but not always. These cameras usually need to warm up, but this one could never be counted on to hold a setting all day long.

Never heard of this! Did you put gaffer tape over the gain pots so the camera operator wouldn't move them?

It has nothing to do with the gain knobs. This is some kind of internal problem with the DVX and HVX cameras. The HVX is usually worse.

I've never really found this an issue with the HVX's.. I find the ones I've worked on pretty solid.

I worked on a DVX100a a few weeks ago and when I put tone through, it took about about 2 minutes for tone to reach its proper level with AGC and all that stuff off. That drove me nuts, but at the same time I was doing double system. No worries!

I've only encountered the problem with the HVX when recording to MiniDV tapes. It's odd.

Yes, but did you put gaffer tape over the gain posts so the cam op doesn't move them???
And how much level variation are you discovering between 20 seconds and 2 minutes?

In this instance, no, I didn't put tape on the controls. I have experienced the same problem on other cameras that I have taped the controls on though. In this case I sent tone to the camera (after making sure the limiter was turned off), and you could see the levels shifting around by themselves over the course of 30 seconds or so. That's why I didn't tape them, because I had to make almost continual adjustments on the damn things. It was really weird. I'd send tone, calibrate. Switch tone off and send it again and bam, it would be way, way off. There were also instances where I would turn up the gain and the levels would move up some and then wouldn't budge no matter how high up I turned the knob. I was just talking to the camera's owner about it yesterday (I told him he really needs to send this thing in, as it's nearly unusable), and he seemed skeptical about it. All told, I'd say I was seeing a variation of 10 dB or so. Scary.