Starting and landing zoom jitter problem

J

jjordache

New member
Hi all,
I got my shinny new DVX100B a few days ago and I noticed a problem wile zooming in and out of the telephoto end. The camera was on a locked and sturdy tripod and while zooming with the VZ StealthPZFI remote control, I can see a very obvious shake or jitter when the servo starts moving the lens.
In a fast zoom it gets covered, but on a slow creep the jitter becomes quite obvious.
I tried all the zoom controls, including the remote control and I got the same result!
I’ve uploaded some test footage here: http://jjordache.googlepages.com/DVX100B_zoom_jitter.wmv if you’re willing to see the problem.
Is this something normal? Has anyone else experienced this issue ?

Thanks much,
Johnny Jordache
 
Your video compression is pretty nasty, but if you are really getting that "stop 'n' start" effect, that's a problem. However, I get this occasionally trying to hold a slow zoom, just because it's hard to find and hold the right pressure. On my spring-loaded remotes and on the camerapressure-sensitive rocker, this happens occasionally; but using my DIY non-spring-loaded remote, it doesn't. So I see it as a pressure regulation issue. You seem to be getting it every time, though, which doesn't seem right.

If you set the camera to zoom only on slow speed, do you get the same thing?

Have you tried flipping the servo/manual switch a few times?
 
Thank you both for your quick replies!
Yes, I tried with both OIS on and off and didn’t see much difference. And flipping the servo/manual switch didn’t improve things either – but good tip anyways, the problem is obviously caused by the DVX’s servo mechanism.

OK, since last night’s panic I searched a little bit more on the forums and found out this is quite a common problem! It happens only when the servo changes direction and is more pronounced at the telephoto end. Putting some light pressure with the index and thumb fingers on the zoom ring helps a bit. On manual I can get pretty smooth zooms, but I’m certain I’m not going to use it that way a lot.

I’m still shocked that I wasn’t aware of this issue, given that A) I worked before with a DVX100A, B) I know several ppl that own the DVX100B and C) I’ve been lurking on these forums for quite a while now…

So, as I understand it we just have to live with it and hopefully with enough practice I can get use to this quirk …

But now I’m wondering if I just happen to have got a worse than average unit?
Any ideas on how I might go about further testing this ? Also, have any of you discussed this issue with the Panasonic support people?

Thanks again!
 
Hey, so just so I understand... if you want to do a zoom, you should first do a quick tick of the zoom in the right direction before rolling, to get the servo going the right way, then you can execute your move? You'll get a better result? Is that right?
 
Joshua Provost said:
Hey, so just so I understand... if you want to do a zoom, you should first do a quick tick of the zoom in the right direction before rolling, to get the servo going the right way, then you can execute your move? You'll get a better result? Is that right?
Click to expand...

Yes, indeed. I nudge the zoom a bit and subsequent zooms in the same direction are significantly smoother at both starting and stopping.
A clean slow zoom is a lot more achievable that way.
But still there's a problem - while I will remember to do this on a controlled shoot, it is more problematic to deal with in the case of a documentary
or live event.
 
Jjordache - I have a DVX100P, so can't, I guess, fully address the 100B, but based on your video you do seem to have an extreme problem if it really does that every time!
 
This is an old issue with the DVX. Pana chose a mechanical zoom with a limited (3) speed servo. A pretty funky design compared to the DVC30, which is butter smooth. You have to "pre-load" the zoom: bump it just a tad in the direction you're zooming prior to the actual move. This can help to minimize the problem, but, as you have discovered, does not eliminate it.
Hope this helps.
Ken
the Screen Skins guy
 
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