Hvx Processing/ccd Error.

J

janusz

Well-known member
On the weekend, I was ACing a show being shot with the HVX, shooting SD to Panasonic's HDV/DV 63min tapes.

There was a considerable amount of smoke/efx fog/dry ice on set for atmosphere.

The camera was sending the video signal via the video-out input to a typical field monitor via BNC and BNC adapter.

On dolly shots ONLY, there were what I called 'Green Strikes' occuring 5 or so seconds apart on the images.

These 'green strikes' looked like pixel lines, horizontally stretching anywhere from half way to 3/4 of width of the image, very thin (About the thickness of the white 90% action safe lines on the LCD) and were bright green, like 'Return of the Jedi' opening credits' font green. They did not appear while shooting, but they did show in playback and ONLY during dolly shots, nowhere else, ever.

Any idea what caused this?

Thanks guys.
 
I had the same type of green plasma colored lines on a shoot this August. The camera was shooting a Foreigner Concert at the New York State Fair. The camera was a handheld in the front of the stage looking up at the lighting grid. The effect you described happened on that camera as well. I remember looking at the concert footage and what happened in my case was whenever this handheld camera would pan the stage I would see a "Green Plasma" vertical line in exactly the same dimensions as you described. after further viewing I determined it was a chrome leg on the drum kit that was reflecting in at a perfect angle combined with the FX/Fog-Haze to create a perfect condition for the dreaded but possible vertical streak. I was just thinking of the possibility that the same thing might be happening on your set. Is there something that might be reflecting only at the "perfect" angle when the dolly is getting positioned to a specific position on your set. Just a thought
 
on one of the dolly moves, there were lights hitting the lens, straight at it, but the intensity of the light was hugely cut down as it was coming through fog/smoke, which was so thick that not even a lens flare was possible.

maybe it was the light hitting the lens. but the second dolly move, there wo no lights hitting the lens at all.
 
the hvx does have vertical straking. its hard to get it ot oocur but it does happen.
 
Vertical streaking is something that happens on CCDs when a very bright light overloads a CCD pixel. The smaller the pixels, the more likely it is to happen; the JVC HD cameras and the PDX10 are champion "streakers". The HVX can be induced to streak but it's difficult.

Horizontal lines? That's not normal.
 
No one else I've spoken with, even the HD guys at Panavision in Toronto who deal with the HVX's, has seen or heard of such issues.

Some say it may have been the stock's magnetism, as we were shooting tape.
 
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