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-   -   Tracers? (https://www.dvinfo.net/forum/sony-trv950-pdx10-companion/19085-tracers.html)

Shawn Mielke January 1st, 2004 05:19 AM

Tracers?
 
Played back on tv some footage from a stage performance I shot last Saturday. It begins with a shot up at and from the side, a man in a spot light, talking and gesturing. Beyond him, only darkness. I shot him a bit hot, unfortunately.

The issue is this: often when he gesticulates with his white hand, some faint but apparent tracers are seen coming off it. Anyone else have this experience? Boyd? I know you shoot in stage lighting.......
Is it because of overexposure, partly? This is somewhat hot white against pitch black......
Is it because of the PDX10's small chips, one of those high contrast smear things? Is it just plain normal?
It's a marvelous shot otherwise!
Thanks,
regards,
Happy '04, friends!
Shawn

Frank Granovski January 1st, 2004 05:57 AM

Shawn, it could be smearing or perhaps flaring/reflection. Perhaps Boyd has experienced this with his PDX.

Boyd Ostroff January 1st, 2004 08:57 AM

When you say "tracers" does that mean a ghost image of the hand follows while it moves? Or is it just a streak? If it's a streak then I suppose it could be another manifestation of the infamous CCD smear. Otherwise???

Nope, sorry, never saw anything like this. Were you shooting at 1/60 sec? It could be overexposure like you say. I expose all my stage shows rather "dense", and almost never burn in a highlight.

Shawn Mielke January 1st, 2004 03:04 PM

Yeah, I had been shooting at the top of the house, but this final performance I decided to shoot from the pit, thought it would make for more engaging video, which it does. But, i didn't have a thorough understanding of the difference in exposure in full wide (in the pit) and mostly telephoto (up top), and, well, it looked ok on the LCD at the time! That's the thing: I'm still new enough to my camera, and dv in general, that I need playback on tv and notetaking to get settings mastered for each particular situation, which I didn't get for this pit shoot.
Anyways, that's my story and I'm sticking to it!

It's not smear as we know it, it's ghostly, well, you know, tracers!
Not horrible, but present.

Would my tv be possibly participating in this phenomenon? I'm going to say it has mostly to do with overexposure/high contrast and try to recreate the setup.........

Boyd Ostroff January 1st, 2004 03:49 PM

Shawn:

Were you shooting in manual mode? If not then I wonder if the camera decided to choose a very slow shutter speed for you. That could create this effect I think. What does the tape data code say for this section?

As far as the TV, the easy answer to this question is to look at individual frames in your editor and see what's really there.

Shawn Mielke January 1st, 2004 04:13 PM

Nope, I'm almost totally in manual, with a shutter speed of 60. It isn't so obviously coming off the moving hand as it is a leftover ghost. I've seen white objects outside that, when too hot, leave a very slight "tail" of motion behind when the cam is moved swiftly (this is on the LCD screen only; haven't actually recorded anything like this before), which is what makes me think it has something to do with overexposure. Again, these things aren't ultra pronounced or obvious. Hope I didn't confuse things with that last bit of commentary.

I don't know much about cam science, but isn't it possible that this is related to the whole vertical smear thing, ie light not succinctly being dealt with by the chips? Is that an inaccurate stretch?

Will check this out in FCE, thanks Boyd. (thanks Frank).

Shawn

Tom Hardwick January 2nd, 2004 09:50 AM

It certainly sounds to me like CCD smear, though you're using pretty slow shutter speeds and the smear is much less noticeable under those conditions. But the CCDs smear under any high contrast lighting - you don't have to be filming fireworks or car headlights to get it.

There is an 'intelligent' spotlight button. When the scene is very evenly lit then the exposure will be the same as 'normal', but if there's a very brightly lit face in a sea of black for instance, then the spotlight mode can make an incredible 4.5 stops correction - and all smoothly and automatically. Have you tried using this feature? It works very well indeed on this camera.

tom.

Shawn Mielke January 2nd, 2004 12:19 PM

Huh! No, I haven't used it, Tom, thanks!

Chris Mueller January 2nd, 2004 05:05 PM

Would you say the tracers are similar to the ghosting effect (I'm assuming because of the tube based imaging devices) in the Queen videos?

Shawn Mielke January 3rd, 2004 02:27 AM

Don't know the Queen videos, sorry.

Today, I was putting around the house, messing with levels etc., and came across this hanging, light, wooden, 3d geometrical piece my girlfriend did. As I was checking it out with the camera, I noticed the same tracer effect when it was somewhat hotly exposed, against a rather shaded wall, as I made little jarring motions with the camera. I toned the exp. down, and no more tracer. More incentive to watch my highlights! Zebras are man's new best friend :-) .

Shawn

Mike Sanchez January 4th, 2004 07:53 PM

Shawn,

I have had one instance, mentioned in another thread, where everything seemed to go awry.

1. Everything was blurry (I don't mean mildly I mean way, way out of focus, even when movement stopped) even though autofocus was on.
2. All white objects suffered blooming, almost as if shooting in light fog.

The incident has not repeated itself but has left me somewhat befuddled. I have an old Canon ES-970 that I've beat on for 5 years and never saw anything like it on that old tech camera.

Shawn Mielke January 4th, 2004 10:41 PM

Hmmm, I've never had autofocus randomly go awry, nor even reasonable moments of auto confusion that lasted more than 2 seconds (it was dark). It's been mentioned elsewhere that OISes can be thrown for a loop by RF, cop radios, that sort of thing. Maybe something related for you? I know it's scary to think that something is wrong with a new cam, even though it's happened only once, but maybe wait and see how it goes?

Shawn


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