Cold Camera

[Alvin Pingol]

I saw a post over at the DV.com forums the other day in which someone recommended tossing your camera in the refrigerator for 24 hours to help recover dead pixels on the CCD.

 

I was just wondering... Has anyone here ever tried it?

 

I'd be tempted to do it if I ever had any dead/hot pixel problems, but am scared about moisture/condensation problems due to the large temperature differences.

 

Don't want any water droplets forming in between the lens elements, on the CCD, in the tape mechanism, etc.

 

So. A go? Or no? :unsure:

[John Pytlak RIP]

I agree that moisture condensation could be a problem, and I have not heard of that "repair".

 

Dead pixels:

 

http://www.cs.wisc.edu/~jduffy/699/

 

http://www.nikonians.org/cgi-bin/dcforum/d...rum=DCForumID84

 

http://www.slashcam.com/advlfaq/722.html

 

http://www.starizona.com/ccd/procadvfilters3.htm

 

http://www.dpchallenge.com/forum.php?actio...THREAD_ID=53940

[Mitch Gross]

Seal the camera in a Ziploc bag with some silica gel if you're worried about moisture. I know that dead pixels begin to show up more as a camera warms up, but I don't know about actually repairing them with cold temperatures. This might only work until the camera warms up again. Cosmic radiation and other damaging waves that injure sensors don't just go away at cold temperatures.

[Alvin Pingol]

Thanks. I guess the fridge thing could work as a temp fix, as you said, but I don't know how long it would work. Since cameras should always be given time to return to the current room temperature before operating, maybe it wouldn't even do anything at all...

 

Damn cosmic rays! :P

[John Pytlak RIP]

Cosmic rays are more potent as you go up in altitude. It's wise to avoid air-shipping unprocessed film and CCD cameras during periods of intense "solar storms".

 

"Dead Pixels" are also a good reason not to point a digital camera at the bright sun.

[Dieter Vansteenwegen]

Cosmic rays are more potent as you go up in altitude.  It's wise  to avoid air-shipping unprocessed film and CCD cameras during periods of intense "solar storms". 

Is this really something you should worry about? I mean like check the condition of the sun before send film?

Never heard anything like that before. Never thought about it either to be honest...

[Phil Rhodes]

Hi,

 

A friend of mine's just had to junk a DXC-D35 camera head because he aimed it at a four-watt Argon effects laser.

 

Oops.

 

Phil

[Landon D. Parks]

I dont think poping the camera in the fridge will revive pixels. Although, weird things happen.

[John Pytlak RIP]

You can check for current "Space Weather" here:

 

http://www.sec.noaa.gov/SWN/

 

The most severe "space storms" can cause damage to sensitive electronics at high altitudes:

 

http://www.sec.noaa.gov/NOAAscales/

 

Severe solar radiation storms can produce the equivalent of several chest x-rays at high altitudes.

[Alessandro Machi]

On the other hand, avoid sending by freight during the summer months as the temperatures probably get to over a hundred degrees. Is putting the film in a lead pouch a possibility?

 

Also, if overnight services travel, um, overnight, would that reduce the risk?

[Alessandro Machi]

I agree that moisture condensation could be a problem, and I have not heard of that "repair".

 

Dead pixels:

 

http://www.cs.wisc.edu/~jduffy/699/

 

http://www.nikonians.org/cgi-bin/dcforum/d...rum=DCForumID84

 

http://www.slashcam.com/advlfaq/722.html

 

http://www.starizona.com/ccd/procadvfilters3.htm

 

http://www.dpchallenge.com/forum.php?actio...THREAD_ID=53940

Some interesting articles. What I got out of the articles is most of the corrections are done later on, and that is much easier to do with a single image than with a motion video camera. Time exposure via digital inevitably will produce either bad dead pixels or "hot" pixels.

 

Usually one dead pixel is not noticeable, usually a cluster of four or more are required before it is noticeable. I can add that some dead pixels aren't noticeable in the normal setting but can be visible on gain. Dust bunnies or dust pixies are different from dead pixels and can be identified by changing the f-stop from f-22 to like f-4, if the shape and sharpness changes, it may be dust, plus the dust pixies are much bigger than dead pixels.

 

the quickest test I know of is to put the camera on the highest gain setting and put a lens cap on the camera and open up the iris all the way, and if you can wait for the camera to warm up that can help identify dead pixels. One of my nicer cameras has a couple of very small dead pixels, but they seem to only show up when I go into higher end gain.

 

Heck, if I need to use extreme gain, then a couple of dead pixels shouldn't matter, right?

[John Pytlak RIP]

A lead pouch for unexposed film will reduce the effects of some kinds of radiation, but may not stop cosmic rays. Lead pouches are NOT effective shields against x-ray security inspection, as the operator typically will increase the x-ray exposure if they see something suspicious in the baggage.

 

The possibility of "dead pixels" depends on the intensity and type of radiation (worse at high altitudes) and the duration of exposure. Yes, solar radiation is less on the shadow side of the earth (night). But you usually cannot control the timing of the shipment.

[John Sprung]

Aren't bad pixels mostly the result of tiny dust particles in the chip fab rather than cosmic ray damage after manufacture? That's what drives down the yield on IC's as the size increases.

 

 

 

-- J.S.

[John Pytlak RIP]

Yes, AFAIK, manufacturing defects probably are the primary source, and excessive numbers of dead pixels cause a reject, or use in a less critical application. But when the number of "dead pixels" increases with the age of the camera, it's likely they are getting "zapped" by high energy particles or excessive heat.

[Xuefei24p]

I had a good laugh about sticking one of my cameras next to the Sam Adams, but, aside from a shocked wife, I doubt it would accomplish much. Perhaps reviewing the tape would be a most effective weight-loss method. Take that, Dr. Atkins.