DVX200 Visual Echo

M

michaelaranda

New member
Hello! I've rented a DVX200 to try out for the next few weeks. With the footage I shot this evening, I've noticed it has some kind of visual echo, with highlights persisting for a few frames. You can see it along the girl's forehead in this clip:


I'm curious if anyone else has experienced a similar issue; I'm sort of at a loss about how to fix it. I've been tweaking settings for a couple hours, but nothing seems to make it go away. I'll keep fiddling, and report back if I figure anything out. In the meantime, if you have any suggestions, I'd be grateful.
 
michaelaranda said:
Hello! I've rented a DVX200 to try out for the next few weeks. With the footage I shot this evening, I've noticed it has some kind of visual echo, with highlights persisting for a few frames. You can see it along the girl's forehead in this clip:


I'm curious if anyone else has experienced a similar issue; I'm sort of at a loss about how to fix it. I've been tweaking settings for a couple hours, but nothing seems to make it go away. I'll keep fiddling, and report back if I figure anything out. In the meantime, if you have any suggestions, I'd be grateful.
Click to expand...

Looks like Noise Reduction/NR Control when set too high. It looks similar to what I've experienced with my HC-X1000 when I had the NR setting on a high setting.
 
michaelaranda said:
Hello! I've rented a DVX200 to try out for the next few weeks. With the footage I shot this evening, I've noticed it has some kind of visual echo, with highlights persisting for a few frames. You can see it along the girl's forehead in this clip:


I'm curious if anyone else has experienced a similar issue; I'm sort of at a loss about how to fix it. I've been tweaking settings for a couple hours, but nothing seems to make it go away. I'll keep fiddling, and report back if I figure anything out. In the meantime, if you have any suggestions, I'd be grateful.
Click to expand...


Looks like the ghosting I get when I don't disable auto resample in Sony Vegas. I also have experienced this shooting interlaced 60i
 
Just to ask more clearly, you're not in auto-shutter? You need to see the shutter speed displayed on the display.
 
Speedster159 said:
Looks like Noise Reduction/NR Control when set too high. It looks similar to what I've experienced with my HC-X1000 when I had the NR setting on a high setting.
Click to expand...

I was shooting in V-LOG at the time, so the camera shouldn't have been doing any noise reduction. I don't think I even have access to those settings when in V-LOG mode.
 
michaelaranda said:
I was shooting in V-LOG at the time, so the camera shouldn't have been doing any noise reduction. I don't think I even have access to those settings when in V-LOG mode.
Click to expand...
On the HPX370 there was something called "PAP" which caused quite a few headaches when the camera first came out. It did exactly as Speedster159 said - noise reduction which gave a less noisy output by working across a number of frames.

The trouble came when there was movement in the shot, and a moving object could leave behind a "ghost trail". Much of the time may not be noticeable, but could be a problem if brought out by post work. (I saw a chroma key sequence rendered effectively unusable by the effect.)

Eventually, Panasonic enabled it to be switchable (and I'd recommend it normally to be left out). From memory, I think the options were "PAP Type 1" and "PAP Type 2" and (I think) Type 1 enables it, Type 2 disables it. So if you found a menu with PAP enabled (or just set to "Type 1") you could have quite aggressive inter-frame noise reduction without being aware of it.

Only other thing I can think of to check is the camera is set to "true" progressive, and not psf - outputting 24p via interlace. (The psf then being incorrectly interpreted.)
 
Two thoughts -- no answers:

1) Did you have the High Sensitivity mode engaged? As I understand it, this is the successor to the PAP mode that harddrive mentioned. I don't know if it works exactly the same way, but should probably be turned off for critical work.

2) Any chance this is something optical? Reflections from a poorly coated protective filter or some such? Make sure the lens hood is on and there's nothing screwed into the front of the lens.

- Greg
 
Greg Smith said:
2) Any chance this is something optical? Reflections from a poorly coated protective filter or some such? Make sure the lens hood is on and there's nothing screwed into the front of the lens.

- Greg
Click to expand...
That seems unlikely, as looking at the original clip the problem is very movement related, and the faster the movement, the greater the separation between "echoes". Which seems to imply it's due to previous frames registering as the "ghosts" - which is why it sounds so similar to me as the original problem with the HPX370, and noise reduction related.

Further to Greg's remark about High Sensitivity mode, what about differing gain settings? Does that make any difference? I'm just wondering if engaging more gain may automatically mean more noise reduction, and hence more "echoing".....? (Even if the operator is not aware it's being switched in.)
 
This is exactly the problem I'm having!

https://youtu.be/AAvAaTXgL10

It's occurring in v-log, the scene file settings and noise reduction settings are all disabled, shutter is constantly manual at 1/50 (PAL) and high sens mode is off. I haven't noticed this in any other footage online, aside from here. Is it a faulty unit? A mystery that has yet to be solved. Barry Green?
 
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I've seen this same problem with my Panasonic AC90. I don't remember getting much help here on the forums about it. It was most noticeable on movement in front of a high contrast background like your example. I seem to remember it being worse with the gain boosted up and slower shutter speeds. Really surprised it to be an issue with the DVX200 which is an expensive camera compared to the AC90.
 
I returned my DVX-200 rental earlier this month, and since then I've been picking through the footage little by little. I've uploaded a couple examples of image-quality issues I've discovered:


I had the camera for about three weeks, and I tried flipping every setting every which-way, but I wasn't ever able to get rid of the weird ghosting thing. I've also experienced some color banding, which I've so far only noticed it in footage that I shot in V-Log mode.

Overall, I think I've gotta say I'm a little disappointed in the DVX-200. For five-grand, I was expecting fewer (or none) of these kinds of image-quality issues. I acknowledge that maybe I just had some settings wrong somewhere, so it might be my own fault, but I feel like I did a pretty thorough test of every setting available to me.

Unrelatedly, the camera is pretty big. Much bigger than I expected. I own an HPX-170, which is already big enough to draw attention when I take it out in public, and the DVX-200 makes the HPX look quite small. I usually try to stay at least SORT OF inconspicuous when filming out in public, but bringing the DVX up to my eye to film felt like I was shouldering a rocket launcher. The DVX200 seems well-suited for studio work where there's plenty of light, or in public settings where you don't mind your camera broadcasting to everyone nearby "I AM A CAMERAMAN AND I AM FILMING RIGHT NOW WITH MY BIG CAMERA".
 
Hi Speedster - the functions on the DVX200 are not exactly the same as the HC-X1000. The NR function doesn't exist in the same capacity. If a firmware update is introduced that more clearly addresses that (ie, an actual NR setting in the menu) that might clear up the problem, but it still wouldn't explain the fact that in V-Log mode, all such functions are disabled and yet it still happens and in the worst way. In V-Log, there is no coring, master detail etc, and high sens mode is off, which is why I have posted ungraded V-Log footage, to illustrate my point. I still haven't come up with a solution to the problem. I'm still using the camera on shoots and it's ok, even great at times, but this is still highly frustrating.
 
Hi Michael,

The ghosting is ugly and I'm still keeping my fingers crossed for an update.
The banding is new to me, but I would say that shooting V-Log internally is not ideal. You're grading 4:2:0 8 bit footage, so it's bound to do that. Eve the FS5 will do it. It's an irritating side effect of the price.
 
OK, as no one asked --

Is that in the original footage (does it look like that if you play it back in the camera), or is that what you see on the timeline?

Because it looks like frame-blending ghosting to me.
 
I believe from my experience with the camera and with the AC90 that this is a motion artifact exacerbated in low-light high-gain situations.
 
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