Rob van Gelder Posted December 1, 2004 Share Posted December 1, 2004 I just did a shooting with a almost brand new (3 months old) Varicam and we had a lot of problems in the beginning because of white pixels that randomly appeared all over the picture. The owner-cameraman (a Thai guy) said he had seen this problem before and to solve it they heated up the camera with tungsten lamps. Being in Thailand I would say the temperature is pretty high already but on this day it was about 22 degrees, still a nice temperature. After a while and countless black balance and black shading procedures the problem disappeared and we could start shooting. Who has seen this before? I find it hard to believe that it was a temperature problem. Link to comment Share on other sites More sharing options...
Premium Member Elhanan Matos Posted December 1, 2004 Premium Member Share Posted December 1, 2004 I have never seen that with a CCD camera before; usually you will get alot of lit pixels if you heat the imager too much. But I have been working with a new camera with a CMOS imager that gets strange artifacting when the imager is too cold. Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted December 2, 2004 Premium Member Share Posted December 2, 2004 Hi, The only thing I know of that causes a random storm of white dots on a CCD is ionising radiation. Usually CCDs have an increasing thermal noise characteristic, so warming it up would make it worse. I suspect instead that this was a processing problem. Computer video boards do this if you try to clock them too fast - random sparkles of white pixels. Within that it could be almost anything - dead or dying ICs, power supply problems, or if the heat issue did seem to solve it, perhaps an interface issue with a connector or socketed IC which was solved by expansion. Conjecture really. Phil Link to comment Share on other sites More sharing options...
Mike Brennan Posted December 4, 2004 Share Posted December 4, 2004 Perhaps ill fitting board. Heating the camera "made" the connection. Similar thing can happen on f900. Did it go to tape? Was it always in the same place on replay? Mike Brennan Link to comment Share on other sites More sharing options...
Rob van Gelder Posted December 5, 2004 Author Share Posted December 5, 2004 (edited) The white pixels flashed randomly, no pattern or fixed places. Probably not longer than one frame. Can´t say if they went to tape too, they didn´t try that, only waited till the problem disappeared. If it was up to me I would have jiggled the cards a bit in their connectors, as that was what I guessed as well. But the people here are very afraid of DIY things, if it doesn´t work as expected out of the box... then just wait till it disappears! A very Thai attitude and it sometimes works. :) Edited December 5, 2004 by RobVanGelder Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted December 5, 2004 Premium Member Share Posted December 5, 2004 Hi, Had any contact with Siam Film Development? Phil Link to comment Share on other sites More sharing options...
Premium Member John Pytlak RIP Posted December 6, 2004 Premium Member Share Posted December 6, 2004 The white pixels flashed randomly, no pattern or fixed places. Probably not longer than one frame. Can´t say if they went to tape too, they didn´t try that, only waited till the problem disappeared. If it was up to me I would have jiggled the cards a bit in their connectors, as that was what I guessed as well. But the people here are very afraid of DIY things, if it doesn´t work as expected out of the box... then just wait till it disappears! A very Thai attitude and it sometimes works. :) <{POST_SNAPBACK}> It does not sound like classic "dead pixels". I'd go with the idea of a poor connection or a digital processing glitch. Heating things makes connections expand and contract, so might have had an effect if that was the cause. Link to comment Share on other sites More sharing options...
Wade Muller HKSC ACS Posted February 6, 2005 Share Posted February 6, 2005 Hi Rob my name is Wade i am also based in Bangkok , just curious where you rented the VariCam from ? , I work out of infocusasia most of the time feel free to drop in and say hi when your free. Link to comment Share on other sites More sharing options...
Mike Brennan Posted February 8, 2005 Share Posted February 8, 2005 Hi Rob my name is Wade i am also based in Bangkok , just curious where you rented the VariCam from ? , I work out of infocusasia most of the time feel free to drop in and say hi when your free. <{POST_SNAPBACK}> On investigation of similar symptoms on a number of SD and HD Sony camcorders Sony Japan say the effect is caused by cosmic radiation 'lighting up' a pixel for a frame. Phil you mentioned ionic radiation, whats that? After worker for 2 0 years with theses cameras and 4 years exclusively with HD why did I only first notice it 6 weeks ago? Mike Brennan Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted February 8, 2005 Premium Member Share Posted February 8, 2005 Hi, Ionising radiation. Given off by radioisotopes - uranium, plutonium, etc. Comprises alpha and beta particles and gamma rays. Latter two particularly dangerous. I saw some terrifying footage interior a rusting Russian naval barge filled with spent nuclear fuel rods, from a small emplaced camera whicih was producing a storm of white noise as the particulate radiation collided with the photosites on the CCD. Phil Link to comment Share on other sites More sharing options...
TJ Williams Posted February 10, 2005 Share Posted February 10, 2005 (edited) We had this same problem last year on a sony HD Cam. Little dancing white pixels all over the screen. Hard to see in the viewfinder but huge on the color monitor and also, sadly, there in playback. We did take of the sides and tried wiggling and tightening everything in site but without avail. Our local tech also tried to wave the magic over it. We rented a backup body and were delayed less than an hour. Kinda wrecks the ole day rate though. After several trips to Sony(US repair facility) and much head shaking. Many different and contradictory explanations, several delays, they finally (appearantly) replaced enough parts to cure this, and this problem has never come back...... Perhaps these things are finally complex enough to produce true "Ghosts in the Machine" it sure makes a little film scratching seem tame.... And OH yes Cosmic Rays..... Which are much heavier in Thailand....I noticed it also when I was there. In fact I got quite burned at the beach.... Our(US) Sony guys had a bunch of explanations but..... even they didn't go there come-on guys equipment failure is just equipment failure.... Edited February 10, 2005 by tjwilliams Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now