disappearing hot pixels

Henrik Joensen · February 18th, 2008, 12:52 PM

marty,

Would be interesting to see your shots of it. Maybe your LIT pixels
will become less noticable if you play with the iris ring.

Marty Hudzik · February 18th, 2008, 01:10 PM

I have my camera and will try to capture a few frames here shortly. On another weird note, I had to adjust my backfocus on the manual lens at lunch, so I had the camera hooked to a 42" LCD while performing this. When I was done, I put the lens cap on and checked for the lit pixels. None. I cranked the gain to +12. Nothing. I changed the shutter to 1/6 sec.....nothing. Okay, maybe at 1/6 I could see a spec....a teeny tiny spec in one of the areas. I was straining to see it. It would not have been visible under normal shooting conditions.

Putting it back to 3db and normal shutter speed and it is clean as....well...something that is very clean!

So I struggle with the intermittent nature of this. I will still try to grab a few frames for you.

Floris van Eck · February 20th, 2008, 07:31 AM

I dropped my camera off at Canon's European repair centre today. It will take 2 to 3 weeks for them to fix this (estimation).

We'll wait and see what happens. One thing that I know for sure is that I am going to do check for this issue weekly once I get it back and while it is still under warranty. It appears that this is a common issue.

Henrik Joensen · February 20th, 2008, 08:57 AM

Floris,

Your camera will sit next to mine as I dropped it off on monday here
in Antwerpen. They told me that Canon here use a Company called
ETB which is Canon's repair technicians, and yes they are in Holland.

Do you know if it is the same repair center your go to?

Floris van Eck · February 20th, 2008, 08:59 AM

Yes, it is ETB in Roosendaal, The Netherlands. It is like a one-hour drive from Antwerpen I think. You could pick it up there if you wanted.

Henrik Joensen · February 20th, 2008, 09:34 AM

Thanks Floris, I'll find them and give them a call if it takes too long.

Floris van Eck · February 25th, 2008, 04:27 PM

The long wait has begun. I can check the status of my repair and it says the camera shipped to repair location and it took two days. I wonder if they shipped my camera to Canon's Repair Center in Irvin, USA. Looks like they did.

Floris van Eck · March 5th, 2008, 07:57 AM

My camera was opened by a technician yesterday, closed on the same day, checked today and the case was closed as well. So I think it will be a few days until I have it back and then I will also learn what they repaired/fixed.

I am very happy that I will soon be reunited with my camera.

Marty Hudzik · March 5th, 2008, 08:35 AM

Good Luck Florence. Canon has always been quick to turn around cameras when I send them in. However, they are often very vague on what they actually do to the camera. I have sent 3 different cameras to them for specific problems and the paperwork returned always says something like "camera checked and returned to manufacturer specifications". Huh?

I had to call and talk to a few people and insist they get me some info before they finally told me they replaced a bad circuit board that was causing noise in the original XL1.

Did you send a detailed description of the issue and some frame grabs to guide them to the bad pixels? I would be concerned because the issue can be intermittent and the day they put it on the test bench may be a "good day" and the tech might not see anything wrong.....hope this is not the case for you.

Thanks,
Marty

Floris van Eck · March 5th, 2008, 09:23 AM

Marty, I shot a reference tape while the problem was imminent and included that in the box which shipped to Canon. So they have a tape, as well as a link to a reference movie I posted on my server, which showed multiple hotpixels around my screen and I also wrote down "my CCD is infested with hot pixels. They are all over the place. Please check thoroughly." I will check the camera straight after I pick it up. If the problem is still there, the camera goes back to Canon but in that scenario I will demand a replacement camera. It takes around 2 - 3 weeks each time and it has been long enough.

Floris van Eck · March 9th, 2008, 06:21 AM

I am picking up my camera tomorrow. I already got a letter from ETB (repair partner) which states: housing cleaned, videoheads cleaned and pixels reconfigured (sounds like pixel mapping).

Marty Hudzik · March 9th, 2008, 10:52 AM

Great to hear! I hope it all works out great for you. I can't remember if you were able to reproduce this at will or not.....were you? If so, it will be great to get it back and change your camera to the exact settings and situation that caused the hot pixels to appear and then know 100% for certain that it is resolved. Personally, I have had experiences where the few hot pixels I have seen have disappeared for a while only to return later....so for me it would be hard to 100% verify immediately if it was fixed.

Thanks.

Floris van Eck · March 9th, 2008, 12:14 PM

I think they will have ways to test this. For example, when you set gain to -18db you have the highest chance of seeing those pixels. But of course they can never be completely sure. We'll just wait and see.

Lou Bruno · March 9th, 2008, 05:20 PM

That is the correct reason due to the increase in (micro) voltage to the pixels in the higher DB range. To see the dead pixels, wrap the camera up in a blanket for an hour and place at the highest DB gain....they will be present.

Quote:

Originally Posted by Marty Hudzik

Off the top of my head I would say that I have seen it 3-4 times in the last year. I was testing a LetusXL the other day and it this adapter eats light for lunch. I was indoors so I stepped up the gain to +6 and I didn't see it. But when I pushed it to +12 they showed up. Then I stepped back down to +6 and they were visible still. All the way down to zero and I could barely make them out.

Later, when I started at 0 they were gone. Is is possible these things actually "heat" up when set to higher gain and then cool down? I wouldn't think so but I guess it is possible cause they aren't there, appear after gaining up and then linger.....hmmmm....

Marty Hudzik · March 9th, 2008, 05:44 PM

That may be true but I recently shot an event in Ohio in February, it was 30 degrees outside and probably not all that warm inside either. I was at +3 gain and the hot pixels were there immediately. I had to go to 0db and use a 1/30th shutter to make up some light. Still, I could see one of these bad boys in several shots.....despite the camera having been "cold". So I think we can rule out that heating up is the only cause of this issue.

This is not a scientific theory, but it seems to occur more often than not with the 20x lens. I can't recall a single time that I have seen these with the 16x manual lens. Just a thought.

Quote:

Originally Posted by Lou Bruno

That is the correct reason due to the increase in (micro) voltage to the pixels in the higher DB range. To see the dead pixels, wrap the camera up in a blanket for an hour and place at the highest DB gain....they will be present.

February 18th, 2008, 12:52 PM	#31
Henrik Joensen Regular Crew Join Date: Dec 2007 Location: Antwerpen - Belgium Posts: 54	marty, Would be interesting to see your shots of it. Maybe your LIT pixels will become less noticable if you play with the iris ring.

February 18th, 2008, 01:10 PM	#32
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	I have my camera and will try to capture a few frames here shortly. On another weird note, I had to adjust my backfocus on the manual lens at lunch, so I had the camera hooked to a 42" LCD while performing this. When I was done, I put the lens cap on and checked for the lit pixels. None. I cranked the gain to +12. Nothing. I changed the shutter to 1/6 sec.....nothing. Okay, maybe at 1/6 I could see a spec....a teeny tiny spec in one of the areas. I was straining to see it. It would not have been visible under normal shooting conditions. Putting it back to 3db and normal shutter speed and it is clean as....well...something that is very clean! So I struggle with the intermittent nature of this. I will still try to grab a few frames for you.

February 20th, 2008, 07:31 AM	#33
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	I dropped my camera off at Canon's European repair centre today. It will take 2 to 3 weeks for them to fix this (estimation). We'll wait and see what happens. One thing that I know for sure is that I am going to do check for this issue weekly once I get it back and while it is still under warranty. It appears that this is a common issue.

February 20th, 2008, 08:57 AM	#34
Henrik Joensen Regular Crew Join Date: Dec 2007 Location: Antwerpen - Belgium Posts: 54	Floris, Your camera will sit next to mine as I dropped it off on monday here in Antwerpen. They told me that Canon here use a Company called ETB which is Canon's repair technicians, and yes they are in Holland. Do you know if it is the same repair center your go to?

February 20th, 2008, 08:59 AM	#35
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	Yes, it is ETB in Roosendaal, The Netherlands. It is like a one-hour drive from Antwerpen I think. You could pick it up there if you wanted.

February 20th, 2008, 09:34 AM	#36
Henrik Joensen Regular Crew Join Date: Dec 2007 Location: Antwerpen - Belgium Posts: 54	Thanks Floris, I'll find them and give them a call if it takes too long.

February 25th, 2008, 04:27 PM	#37
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	The long wait has begun. I can check the status of my repair and it says the camera shipped to repair location and it took two days. I wonder if they shipped my camera to Canon's Repair Center in Irvin, USA. Looks like they did.

March 5th, 2008, 07:57 AM	#38
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	My camera was opened by a technician yesterday, closed on the same day, checked today and the case was closed as well. So I think it will be a few days until I have it back and then I will also learn what they repaired/fixed. I am very happy that I will soon be reunited with my camera.

March 5th, 2008, 08:35 AM	#39
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	Good Luck Florence. Canon has always been quick to turn around cameras when I send them in. However, they are often very vague on what they actually do to the camera. I have sent 3 different cameras to them for specific problems and the paperwork returned always says something like "camera checked and returned to manufacturer specifications". Huh? I had to call and talk to a few people and insist they get me some info before they finally told me they replaced a bad circuit board that was causing noise in the original XL1. Did you send a detailed description of the issue and some frame grabs to guide them to the bad pixels? I would be concerned because the issue can be intermittent and the day they put it on the test bench may be a "good day" and the tech might not see anything wrong.....hope this is not the case for you. Thanks, Marty

March 5th, 2008, 09:23 AM	#40
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	Marty, I shot a reference tape while the problem was imminent and included that in the box which shipped to Canon. So they have a tape, as well as a link to a reference movie I posted on my server, which showed multiple hotpixels around my screen and I also wrote down "my CCD is infested with hot pixels. They are all over the place. Please check thoroughly." I will check the camera straight after I pick it up. If the problem is still there, the camera goes back to Canon but in that scenario I will demand a replacement camera. It takes around 2 - 3 weeks each time and it has been long enough.

March 9th, 2008, 06:21 AM	#41
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	I am picking up my camera tomorrow. I already got a letter from ETB (repair partner) which states: housing cleaned, videoheads cleaned and pixels reconfigured (sounds like pixel mapping).

March 9th, 2008, 10:52 AM	#42
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	Great to hear! I hope it all works out great for you. I can't remember if you were able to reproduce this at will or not.....were you? If so, it will be great to get it back and change your camera to the exact settings and situation that caused the hot pixels to appear and then know 100% for certain that it is resolved. Personally, I have had experiences where the few hot pixels I have seen have disappeared for a while only to return later....so for me it would be hard to 100% verify immediately if it was fixed. Thanks.

March 9th, 2008, 12:14 PM	#43
Floris van Eck Major Player Join Date: Jan 2006 Location: The Netherlands Posts: 993	I think they will have ways to test this. For example, when you set gain to -18db you have the highest chance of seeing those pixels. But of course they can never be completely sure. We'll just wait and see.