Do tin foil hats work?

bwana

bwana

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Because I want to try and block some RF interference being caused by a Canon 580EX II.
 
Choose one :)

Why can't I just use lead or copper or aluminum foil for magnetic shielding?

In the strictest sense, magnetic shielding is not truly shielding at all. Unlike the way a lead shield stops X-rays, magnetic shielding materials create an area of lower magnetic field in their vicinity by attracting the magnetic field lines to themselves. The physical property which allows them to do this is called "permeability".

Unlike X-rays, sound, light or bullets, magnetic field lines must travel from the North pole of the source and return to the South pole. Under usual circumstances, they will travel through air, which by definition has a permeability of "1". But if a material with a higher permeability is nearby, the magnetic field lines, efficient creatures that they are, will travel the path of least resistance (through the higher permeability material), leaving less magnetic field in the surrounding air.

Here's how the permeabilities of some common materials compare:
Air ........... 1
Copper ...... 1
Aluminum ... 1
Tin ............. 1
Lead .......... 1
Nickel .................. 100
Commercial Iron ... 200
Stainless Steel ....... 200
MagnetShield ........ 4000
Magnetic Shielding Alloys* ....... 20,000+
Annealed MetGlas ................. 1,000,000
* such as Magnetic Shielding Foil, Mag-Stop Plates, and Joint-Shield

Now it is easier to see why a magnetic shield in the shape of an enclosure (sphere, box, tube, etc.) offers much better shielding than a flat shape or partial enclosure. A source within the shield will produce field lines which will travel through the air immediately surrounding the North pole until they reach the shield. Then traveling through the shield, they will emerge into the air surrounding the South pole and back to the source. Traveling through the low permeability air outside the shield does not offer any efficiency advantage! (Notice that the diagram to the right is a cut-away view of a tube shaped shield.)
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Basic Shielding Protection
Our Aluminum RF Shielding Mesh is high quality, durable, non corrosive conductive mesh.
Click to expand...
 
Well, where do you get tin foil? All the stuff you buy for cooking is aluminum (pr. alumin-num as you from US :p) foil and has been since the 1940's.
 
Maybe it will work - considering how inexpensive it will be to test I think it's worth a shot.
Scientific basis

The notion that a tin foil hat can significantly reduce the intensity of incident radio frequency radiation on the wearer's brain has some scientific validity, as the effect of strong radio waves has been documented for quite some time.[3] A well-constructed tin foil enclosure would approximate a Faraday cage, reducing the amount of (typically harmless) radiofrequency electromagnetic radiation passing through to the interior of the structure. A common high school physics demonstration involves placing an AM radio on tin foil, and then covering the radio with a metal bucket. This leads to a noticeable reduction in signal strength. The efficiency of such an enclosure in blocking such radiation depends on the thickness of the tin foil, as dictated by the skin depth, the distance the radiation can propagate in a particular non-ideal conductor. For half-millimetre-thick tin foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked, although tin foil is not sold in this thickness, so numerous layers of tin foil would be required to achieve this effect.[4]
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If it's a bust then there's always the $13 option - http://www.bhphotovideo.com/c/product/728257-REG/PocketWizard_804_704_AC5_RF_Soft_Shield.html
 
Reminds me of the "Tracked by satellite" thread from a few years ago.
 
noswal said:
Well, where do you get tin foil? All the stuff you buy for cooking is aluminum (pr. alumin-num as you from US :p) foil and has been since the 1940's.
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actually, it's aluminium. The Yanks spell it without the last 'i', hence their pronunciation of the word.
 
koffiejunkie said:
I'm curious - what are you doing for this to be a problem?
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Wireless receivers/transceivers; the 580EX II apparently emits some pretty crazy RF interference in a wide spectrum that can drastically cut down on the range of some receivers/transceivers. Go have a look at the bhphoto link bwana posted for a visual example of a jacket for the flash.

Just another reason I'm happy with my cheapo Yongnuo flash - apparently it doesn't have that problem :p
 
koffiejunkie said:
I'm curious - what are you doing for this to be a problem?
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as nanonyous mentioned - the 580exII's seem to have a RF problem that interferes with the pocketwizards - some foil seems to have mitigated it but the obvious solution is to just use a longer sync cable me thinks.

nanonyous said:
Wireless receivers/transceivers; the 580EX II apparently emits some pretty crazy RF interference in a wide spectrum that can drastically cut down on the range of some receivers/transceivers. Go have a look at the bhphoto link bwana posted for a visual example of a jacket for the flash.

Just another reason I'm happy with my cheapo Yongnuo flash - apparently it doesn't have that problem :p
Click to expand...
Just had a look at the Yongnuo's and they look pretty decent but I think I'm going to get a proper strobe and softbox next.

I didn't really get the PWs with flashes in mind so I'm not particularly bothered by the current range (aprox 90m).
 
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