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Missing pixels and high altitude


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#1 Tony Yates

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Posted 16 July 2007 - 05:19 AM

Over the last year or so I have noticed a lot of problems with missing pixels on the HDCam cameras I have been using. Are they more prone to this problem ?
Someone told me that they can loose a lot of pixels if they are involved in airline transport because of the high altitude. Is this just a myth or is it true and if so is there a way of protecting the block when flying a lot ?
Tony
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#2 Mitch Gross

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Posted 16 July 2007 - 09:52 AM

Nope.

It's called gamma radiation, and there's nothing that can be done about it.
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#3 Tony Yates

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Posted 17 July 2007 - 10:21 AM

Thanks Mitch - its always worrying to see a line like "theres nothing that can be done about it" !
Is this something that builds up through regular flights or can it effect the camera block on just one flight ? Is it more severe in the hold than in the cabin ? Am I being paranoid to consider road transport over air to minimize the possible damage to my camera ?
Tony
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#4 Mitch Gross

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Posted 17 July 2007 - 01:13 PM

It builds up over time. It has become more and more of an issue as the available HD cameras get older and older. Where in the plane means nothing. You gotta do what you gotta do and travelling by ground may be impractical. But I can tell you that both Sony and Panasonic ship their cameras by boat not air from Japan to the US exclusively in part to mitigate this issue.
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#5 Tony Yates

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Posted 17 July 2007 - 04:22 PM

Thanks Mitch -
Your posts have been really useful for me. I have just bought an HD camera here in the UK and am filming in Italy next month. There is a van going to the location with some gear and wardrobe but I was going to take my camera with me on my flight as handbaggage - I think I might just put it on that van now !!
cheers
tony
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#6 Hal Smith

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Posted 17 July 2007 - 05:02 PM

It seems to me that a lead-lined shipping box would help this problem. If the manufacturers have any hard data on just how energetic a gamma ray photon has to be to kill a pixel it would be pretty straight forward to calculate just how much lead would be required for sufficient shielding for air travel.

The worst case would be to take a camera up in the air during a magnetic storm generated by sunspots.

http://esa-spaceweat...ndex.html#index has current solar weather conditions.

http://www.sec.noaa.gov/ is also useful.
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#7 Tony Yates

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Posted 18 July 2007 - 03:37 AM

Does stuff like high intensity radar and x-rays also effect the camera block or is it just gamma rays ?
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#8 Mitch Gross

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Posted 18 July 2007 - 11:23 AM

Just gamma rays. And it would take a lead-lined box 3 feet think to defeat the same gamma rays as our atmosphere. Untold millions of them pass through your body every day and when scientists wish to limit the number to measure them they use a tank of water deap inside a mine shaft.
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#9 Tony Yates

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Posted 18 July 2007 - 12:36 PM

Sounds like a cave diving documentary is safest for the camera !!........ although that might be a bit dangerous for me !
tony
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#10 John Sprung

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Posted 18 July 2007 - 01:16 PM

Just gamma rays. And it would take a lead-lined box 3 feet think to defeat the same gamma rays as our atmosphere. Untold millions of them pass through your body every day and when scientists wish to limit the number to measure them they use a tank of water deap inside a mine shaft.

That's a lot of lead, not too practical for regular air transport. Maybe they could make the lens mount and chip into a removable module that could be shipped in a much smaller lead box, just a few inches thick. How much better would that be than sending the camera without shielding? Pulling just the chip or optical block would give you a back focal issue putting it together on location.

I'd guess that CMOS and CCD would be about equally vulnerable, they're both made of the same semiconductor material, right?

Come to think of it, how do they protect cameras in space, like the Hubble telescope and the KH-12 spy satellites?



-- J.S.
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#11 Mike Brennan

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Posted 18 July 2007 - 02:36 PM

Personally I had not noticed nor any of my owner operator friends could pin point pixel loss to airline travel, when this question was ressurected by the pro film community in 2001.



Facility companies in UK had int he ninties reported loss of pixels on brand new SD cameras, shipped by air over the north pole route.

When HD came along we became a little fussy. Sony began shipping by sea and the problem apparently diminished. (not sure of the dates on this)

But many owner operators travel on multiple flights for years with no apparent harm.
A friend has had 32 flights with a f950 in the last three months without a problem.
SO either pradiation has more of an effect on a new camera or pixle masking is hiding the real number of dead pixels.



My theory based on this evidence is that some pixels are more susceptable to failure in flight than others.
It is posible that the factory pass the ccd block as OK but when it is shipped by air travel these "prone to failure" pixels would die.

The two large Rental compaies in UK reported that they had never had a near new camera returned with failed pixels that could be attributed to air travel during the days when the cameras were shipped by air.

But now they are shipped by sea they occasionally get a near new camera back from a purchaser with failed pixels.

My theory is that every new camera should have a flight to put it through the wringer to find any susceptable pixels.

It seems that after a few flights likely hood of pixel loss is remote.

Also how many digital stills camera criss crossing the globe that also should be affected...

An ideal sample group digital camera touting professional pilots....


That's my theory for the day anyway!


Mike Brennan
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