Numerous dead pixels appear...then disappear? at DVinfo.net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XH Series HDV Camcorders

Canon XH Series HDV Camcorders
Canon XH G1S / G1 (with SDI), Canon XH A1S / A1 (without SDI).


Reply
 
Thread Tools Search this Thread
Old January 7th, 2011, 09:26 PM   #1
Regular Crew
 
Join Date: Mar 2007
Location: Canton, NC
Posts: 48
Numerous dead pixels appear...then disappear?

I was shooting some family video on Christmas day with my XH-A1 which is now going on 4 years old (purchased March 2007). I transferred that footage to DVD today and noticed that from one shot to the next, about 7 dead pixels suddenly appeared scattered across the screen. There may be more, because at first I only saw 3, but on different shots, with more dark areas, I was able to count at least 7. Anyway, they're all there for a couple minutes worth of footage and then they vanish between shots. Not a single one anywhere on the image after that. Nothing changed as far as settings go. Gain was on +12 dB (dimly lit house) the whole time, shooting 24F, with shutter speed at 1/24. Those settings were left alone and as far as I can remember, the camera was not even turned off before the point the dead pixels vanished. Fortunately, they haven't reappeared in any footage shot since then.

This is the first time I've noticed anything like this on this camera. What would cause that many dead pixels (if you can call them that, since they are not permanently "dead"...yet) to suddenly appear and then just as suddenly disappear? Hopefully this is not a warning sign that something's about to go wrong with the camera.
Doug Chambers is offline   Reply With Quote
Old January 8th, 2011, 12:29 PM   #2
Major Player
 
Join Date: Mar 2010
Location: Red Lodge, Montana
Posts: 889
I've run into a couple of things that have caused this.

Assuming that you were recording to tape, have you tried playing the actual tape with the camera hooked to a large screen tv?

If you do not see dead spots during playback, you had a problem with tape capture. Try recapturing the segment where you saw the problems.

If you see the same dead spots at the same places during playback from the camera, the problem is most likely some bad spots on the tape. If one tape is bad, the batch of them will be bad, too. There was a thread last summer about a batch of problem tapes from, I think, Sony. As I recall, specific batch numbers were identified.

If dead spots occur in different places, then you've got most likely got a problem with the recording heads. They may be worn, dirty or possibly a bit out of alignment. You can try a cleaning tape or send the camera in for service to a Canon Service Center. When I sent my XH in for service last summer, there was a flat rate charge of $325 plus shipping.
Jay West is offline   Reply With Quote
Old January 9th, 2011, 02:07 PM   #3
Major Player
 
Join Date: Mar 2010
Location: Red Lodge, Montana
Posts: 889
One additional thought. If you had not checked your footage on your computer before conversion to DVD, and there aren't bad pixels in the captured clips, then you've got an issue with the encoding or DVD authoring software.
Jay West is offline   Reply With Quote
Old January 10th, 2011, 05:02 AM   #4
Major Player
 
Join Date: Apr 2006
Location: Sweden
Posts: 244
Hi

I've also seen a few white pixels from time to time, especially using high gain and in dark areas of the picture. It's a long time since I saw them now so they seems to vave disappeared in som magic way.
If they appear, it might be possible to mask in them some way during post.

Regards,

/Bo
Bo Sundvall is offline   Reply With Quote
Old January 10th, 2011, 09:11 AM   #5
Regular Crew
 
Join Date: Feb 2010
Location: S. Ozone Park
Posts: 25
This is normal..

This phenomena is know as "hot pixels". It occurs when the CCD gets too hot, causing a few pixels to get "stuck".

If you place your camera in "night mode", you will notice many "hot/stuck" pixels appear on the screen. Turn your camera off for a few minutes, and then back on into "manual" mode, you'll notice the hot pixels are gone.

It's normal behaviour, every camera does this. To avoid this problem, do not film at high gains, or slow shutter speeds.
Alex Lafkovici is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XH Series HDV Camcorders

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 06:07 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network