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Old March 1st, 2008, 07:17 PM   #1
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aCk ... wobbly vid

Just got my brand spankin new Sachtler and took it out to the driveway to play with it. Looking at the footage I was pretty taken aback to saw this wobbly, swishy, watery, effect. Not sure what I was doing, I assume adjusting the tripod or something, the moment it happened but nothing even remotely "violent". While I love the camera this little tidbit has me a bit horrified, just thinking if this had been a real shoot. Would love any insight. It happens at around 9 seconds in.

Image stabilizer was off btw, another afterthought after rereading my post.

http://www.vimeo.com/743587

- Ray

Edit : If you're having problems seeing it try downloading it. There's a link on the bottom right "Download Quicktime version"
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Old March 1st, 2008, 08:52 PM   #2
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That's the rolling shutter - in fact I think this type of thing is much more of an issue than the examples people usually cite (trees/lamp posts leaning during pans). It mostly shows up with high frequency, short-travel movement like you've got there.

It's certainly an issue to be aware of, but I think it has to be taken in context - with your shot, for instance, even without the wobble effect I would consider the shot ruined if it shook like that because I bumped the tripod or made a camera adjustment. You say it has you horrified thinking 'what if it had been a real shoot' - well, what if it had been? The main problem isn't the wobble, it's that you did something to cause your camera to shake in the middle of the shot and you either need to avoid that or try a different tripod (maybe the vinten fibertec?)
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Old March 1st, 2008, 09:01 PM   #3
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It's the Sachtler FSB-6 Carbon Tripod System with FSB-6 Fluid Head, 2-Stage Tripod, Mid-Level Spreader ... great tripod.

I understand your point in theory but there's a huge difference, to me at least, between a bounce in the camera and this swishy imaging. As I said, I think I was adjusting the tripod but nothing that I would consider this kind of behavior from the camera to be acceptable.

- Ray
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Old March 1st, 2008, 09:39 PM   #4
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Hi Raymond..........

BTW, thanks for the plug, Evan!

Well, I've given that bit of video a seriously intense scrute, and, apart from the jello camera support (that tripod/ head system has serious issues!) the only thing that stands out is the fairly serious focus hunting going on between the cars in the background and those branches/ twigs in the forground.

Considering the EX1 has only a 14 (is that correct?) X zoom (assuming that clip was taken at max zoom in) then the amount of support wobble indicated is trully frightening. I couldn't induce that in my FiberTecs (even @ 20 X zoom) if I threw a flying drop kick at them.

There's either sommat broke or I think it's back to the drawing board on the support front. Fix that and turn off Auto Focus with that type of framing and I think you'll probably have cracked it.


CS

PS. B&H still do have FiberTecs in stock despite them being discontinued.
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Old March 1st, 2008, 10:31 PM   #5
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I guess you guys aren't seeing what I'm seeing or it's just not coming through in the version I posted as clear as it does in its source. The "obvious" tripod movements have nothing to do with the what I'm talking about and are irrelevant aside from that it was in moving and adjusting the tripod that the "wobbly, swishy, watery" anomaly became present and visible. Not sure what other adjective to use. The focus is also irrelevant. These weren't supposed to be keeper shots, I just didn't hit pause because, well, I didn't need to. I wasn't doing any serious shooting, just wanted to take out the new tripod. It was only in playing back that I saw what I'm seeing by happenstance. And my point is that a little wobble should not cause the "wobbly, swishy, watery" effect in camera that I'm seeing. These were minor movements, and hence my concern. I personally have never had seen this in any camera previous and I put them through their paces much more than this.

- Ray
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Old March 1st, 2008, 10:58 PM   #6
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Quote:
Originally Posted by Raymond Schlogel View Post
I personally have never had seen this in any camera previous and I put them through their paces much more than this.

- Ray

Apparently you're not talking about a CMOS camera here. CMOS camera's with their rolling shutter have this issue.

This is normal for the EX1 under these conditions. I have no issue. Just as Red users are dealing with these "possible" issues, I knew about it when I bought it.

I would not of kept this shot wobble or not. If you're looking for a camera that can take this movement, you may want to sell the EX1 quick.
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Old March 1st, 2008, 11:58 PM   #7
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Any piece of equipment has to be used with its capabilities and shortcomings in mind.

If I wanted to provide daylight fill in an outdoor scene, for example, I'd use a reflector or an HMI. I wouldn't try to fill a table-sized scene with a VidLED.

If I'm shooting in low light conditions I wouldn't use an HVX.

And if I expected a lot of vibration, I'd find a way to ensure a stable mount or avoid using a CMOS camera.

The effect you're seeing is real, but to the average viewer is it significant enough to be objectionable? To my eyes, camera shake and focus problems are serious issues. The slight "jello" wobble is brief and inconsequential by comparison. And the wobble shows up only when there's an objectionable shake. So for me it's not a problem I'd worry about.
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Old March 2nd, 2008, 12:53 AM   #8
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Hi Ray.................

Ok, well, after your last post I had yet another serious scrute, discarded the support issues and hunting focus and, yes, I can see what you mean.

The "wave" that runs through those few frames is quite nauseating.

Not something I've ever seen with my Canon A1 (thank God) but guess that's what happens when you buy a CMOS camera.

(I'm taking everyones word for it, still don't have a clue what this "rolling shutter" is all about - anybody like to point me to a decent explanation?).

Suggestions?

Hah!

Get a better tripod system so it can't "wobble"?

Turn off Auto Focus?

Don't do stuff that CMOS cameras can't do?

(Does anyone have a definative list of what CMOS cameras can't do?).

Quite frankly, I'm exceedingly glad that when I was asked some time ago whether I'd upgraded from my Canon A1 to an EX1, my response was: Why? (and felt no remorse whatsoever).

HDV has it's problems, but the EX1 seems to be a case of "Out of the frying pan, into the fire".

Not that this is helping you any Ray. Work on fixing the support problem and maybe there's a work around possible for this "wave".


CS
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Old March 2nd, 2008, 01:10 AM   #9
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Looks like auto focus hunting to me and a shaky cameraman with a unbalanced camera. Try locking it off, and setting focus... just my 2 cents before panicking....
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Old March 2nd, 2008, 01:20 AM   #10
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I was aware that this could happen under extreme circumstance. As I recall in the video that had been posted here some time ago that exhibited this behavior, the camera was being fairly violently shaken. This was far from that nature and I am fairly shocked that it showed up in mine with just a fairly subtle adjustment of the tripod. Keep in mind it was fully zoomed so it doesn't take much movement for the zoomed in image to move like it did. Much less vibration than I would expect for this issue to be triggered.

And auto focus was not on.

- Ray
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Old March 2nd, 2008, 01:43 AM   #11
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Here's an example of shooting from a boat. Some of you might have seen this already.

http://www.hawaiigoesfishing.com/videos/pwc_test.mov

You may have to download before viewing for best results. It's 720p30 compressed with the h.264 codec.

The boat's moving, the jet skis are moving. I'm moving. I threw up after lunch but that's a different story... :-)

All shots were handheld.

One shot is soft but that's because I made the mistake of shooting at f16. Now I avoid anything below f11.

I think what helps is preventing the camera from making any sudden lateral movements, especially oscillating motions. If I were to shoot aerials from a helicopter with an EX1 I'd make sure the camera is properly isolated from vibrations. Of course I'd do that with any camera but I'd be particularly careful with an EX1.
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Old March 2nd, 2008, 03:24 AM   #12
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Well, Ray............

If autofocus wasn't on, I'd like someone to explain what is happening with the focus on that clip.

The twigs are in focus, then they aren't, then they are. The car (far left background) is in focus, then it isn't, then it is. The "Stop" sign is wandering in an out like a drunk in a boozer.

There is no way on this planet that "Auto" wasn't doing something. Else the EX1 has a mind completely of it's own. Or you were varying the focus manually?

Got to be one of those three.

Rolling shutter (whatever that is) doesn't (surely?) make things go in and out of focus like that.

CS
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Old March 2nd, 2008, 08:42 AM   #13
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I recommend you the following practice, which has give me very good results a lot of times: show your footage to someone who knows nothing (or very little) about video, specifically with zero knowledge about technical stuff. Don't tell him anything, just say: "I'm going to show you something I'm not quite happy with, tell me if you can see something wrong with this video". I do this when I start to be obsessed with something, and it always has showed me if there really was something to worry about, or if I was loosing time (and my temper) with something that nobody could see (except me). The viewer shouldn't know what the problem is, just that maybe there's something wrong, because if you tell them "can you see a wobble effect in that image", everybody will say "yes" even if it was shot with an F-23. If an average viewer can't notice a problem, even if he is hunting an undetermined one, then we can assume that it won't be noticeable for people who is more concerned about what they're seeing than how they see it.

An example: a few weeks ago, I had to digitize an old Betacam master tape. It had been stored on a shelve for almost ten years since the editing was done and never played back again until I had to rescue it. I had a lot of problems to digitize it, the heads of the Beta deck got clogged again and again, even after winding the tape back and forth several times. Then, when I examined the footage closely, I only could see drop outs, everywhere... so I started to clean it, at every frame there was a drop-out, I cleaned it... I was doing that tedious job, when Bo$$ came to see what the h*** I was doing. I showed him the "original" and "restored" version, and he told me: Apart from a few very noticeable ones, I can see no difference. That video looks great (I shoot it myself), so don't loose time with this and go on with your job.

And then I could see a great video about pottery, and not an old Betacam tape full of drop outs.
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Old March 3rd, 2008, 01:11 AM   #14
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Quote:
Originally Posted by Dean Sensui View Post
The effect you're seeing is real, but to the average viewer is it significant enough to be objectionable? To my eyes, camera shake and focus problems are serious issues. The slight "jello" wobble is brief and inconsequential by comparison. And the wobble shows up only when there's an objectionable shake. So for me it's not a problem I'd worry about.
Exactly, that was my point too - before my XH-A1 I had sony's first CMOS HDV camera, the HC1, and in situations like this it exhibited more wobble than the EX1 appears to. I never found it to be a problem though because any situation where the wobble showed up was already a shot I never would have used because of the shake. I actually expected this to show up in the EX and still plan to replace my A1 with it because it's just not much of an issue in real world use.
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