Digital Cameras and Magnets

[brembo]

With most type media using magnetic storage, what kind of effect would placing a digital camera (Canon A80 now, D70 or alike in the future) near a strong magnet have on the camera itself, and the media in it?

I'm looking for a tank bag for my motorcycle for some added storage space. The tank bag itself attaches to the fuel tank of my bike via rather large, very strong magnets. How strong? There's 4 or so magnets, which can keep the bag in place while the bike is going 150kph+.

I take my A80 almost everywhere, and so far the thought of having said magnets near my digicam, and potentially losing all my photos, has put me off.

[gstark]

Damn good question.

The issue I think relates to storage, and as long as you're using solid state storage - a proper CF card, as distinct from a microdrive - I think there would be no issue.

[MCWB]

Brembo: I don't think you'll have much of a problem. At the uni I work in, we have a mission critical laptop positioned about 4 m or so from a 14.1 Tesla magnet. You can see it on the right of this picture.



I know from personal experience that this magnet will wipe your credit cards if you stand next to it with your wallet in your pocket , so if you can get a laptop that close to such a strong magnet, I don't reckon you've got any problems with the magnets in your bag. I don't *know* for sure though. If it is a problem, the further the camera is away from the magnets the better off you'll be though, as the magnetic field strength drops off with distance cubed (e.g. double the distance, 1/8 th of the field strength).

[brembo]

I know from personal experience that this magnet will wipe your credit cards if you stand next to it with your wallet in your pocket

The credit card thing completely slipped my mind, being such fragile things as they are, they really need to find something more durable.

And that 1.41 Tesla magnet/laptop thing sort of puts my mind to rest.

OT: Which Uni do you work for?

[christiand]

Merry Christmas MCWB,

was the tesla magnet in operation when you took the photo ?
(with the D70 I assume)
In Canberra at the Questacon they have a Tesla transformer to generate 3.5 Million volts.
They use that for generating lightning.
This all done within a Faraydian cage.
There are no warning signs for people carrying pacemakers.
I assume this also so a safe environmet (outside the Faraydian cage) when taking photos with the D70 ?

Cheers
CD

[MCWB]

brembo: Sydney Uni.

Christian: different animal I'm afraid. The thing at Questacon is a Tesla coil, it generates electricity. The thing in the photo is a superconducting magnet, so there's no Faraday cage. "Tesla" is a unit of magnetic field strength. You're right, if you have a pacemaker or other magnetism-sensitive items in your body then you're not allowed to enter (and there are warning signs on the door). This includes tradesmen carrying iron items etc too, access is strictly controlled. And yes it's perfectly safe to take the photo from where I took it, the magnetic field strength is pretty small there.

[christiand]

Thanks MCWB,

I might go to Questacon with the D70 and study lightning photography.

Cheers
CD

[brembo]

That's actually not a bad idea, no need to worry about waiting for a storm to come to you, go straight to Quesatcon which has 'On Que' lightning.

[MCWB]

I might go to Questacon with the D70 and study lightning photography.

That sounds like a really good idea actually, good one! Might have to try that when I'm down there in January.

[lukeo]

Dans Letters awhile back had some extensive links to magnets and their effectives on gadgets. Rare earth metal magnets are available with stregnths upto 1 Tesla, these are just barely enough with the tip to do damage to a credit card. CF cards, computer hard drives etc etc can have one of these rested on the 24/7 and do no damage at all.

To wipe CF you are really talking very serious magnetic power, and a rapidly changing electromagnetic field will be many times more devasting. A giant super magnetic as above switched on and off electronically at a rate of say 1000hz (1000 times a second) might just do some damage ...

still remember people kids and rapidly changing electromagnetic fields are never a good idea.