Strong Magnetic fields - Can they affect CF data?

Discussion in 'Mirrorless Digital Cameras' started by don_bryant|2, Jun 25, 2007.

  1. Hi Friends,

    Recently a friend asked me if a strong magnetic field can affect data stored on
    a CF card (or SD card). My initial response was that I didn't think so but I'm
    really not certain what the effect of a strong magnetic field might be on a CF
    card.

    Does anyone know the answer to this?

    Thanks!
     
  2. Hi Donald,

    CFs aren't magnetic media, so they can't be erased like, say, a floppy disk or a hard drive. However, depending on the strength of the magnetic field, a CF isn't *completely* safe. For instance, if you were to do an MRI of your CF (or any other piece of sensitive electronic circuitry, for that matter), it would be toast. It's not simply the strength of the magnetic field that matters, so much as the rate at which the field changes. If you go from strong field to no field very quickly or vice versa, then the change in magnetic flux can generate small voltages over wires, traces, etc. If the voltages are high enough, then they can cause damage. I don't know, practically, in the real world, what sources of magnetic fields might pose a danger to a CF -- or a camera -- or a lens.

    Hope that helps!

    Peace,
    Sarah
     
  3. If CF cards are not magnetic, and not optical like film then just what are they?
     
  4. In simple terms, Cf are based on Flash memory. It is neither magnetic nor optical but
    electrical. The memory site either holds an electron or not and whether current can flow
    from the site or not. Hope this helps. Sandy
     
  5. http://electronics.howstuffworks.com/flash-memory.htm

    http://en.wikipedia.org/wiki/Flash_memory

    I'm not sure of any typical environmental magnetic fields which would damage most non-magnetic memory type devices or most other consumer electronics for that matter. Magnetic media like tapes, disks, can be damaged and CRTs can be distorted some.
     
  6. Hey, what I'm impressed with is the fact that the first two technical answers were written by females. (assuming Sandy is female, but you never know for sure about some names) It sort of flies in the face of the usual gender biased assumptions our society fosters. Kind of like, "girls don't do math." Every once in a while it's good to get dragged outside my little box. Thank you.
     
  7. Hi Folks,

    Thanks for the thoughtful replys. I (and my friend) both understand how data is stored on the CF cards but neither of us were knowledgeble <sp?> about the effect of strong magnetic fields on the data stored there. I supposed that the simple answer as Sarah points out is that strong magnetic flux could affect data storage.

    Once again thanks!
     
  8. >what I'm impressed with is the fact that the first two technical answers were written by females. (assuming Sandy is female, but you never know for sure about some names)

    Does every user choose a screen name according to his/her real gender? What's there to prevent a woman from using a guy's handle or vice versa?
     
  9. Anyone here have spare CF card to throw away? YOu can place it besides a strong magnet for 2 days and let us know what happens. So that we'll know the answer to this query.

    And no, I dont have a spare CF card to throw away , yet :D
     
  10. I think esd - electrostatic discharge is far more likely to cause problems than magnetic fields, stray "radiation," etc. Improper handling of a memory card, somehow discharging while holding a finger across/near an open connector, or something like that. Cards are usually the only thing that we come into contact with conductors on or sometimes a connector of some sort.

    I'd bet we still have a lot more damage from traditional "oops's" like drops, water spray or rain, tripod tips, fumble fingers. setting the camera down in an unsade spot, and the like.
     
  11. It depends what you mean by strong magnetic field. It is not recommended to even try using a digital camera anywhere too close to an NMR medical scanner, or an aluminium smelting line, both of which produce very strong magnetic fields that will upset the camera let alone a memory card. In both cases, a film camera with mechanical shutter and non-magnetic metal content (brass lens barrel, probably wooden body etc.) are needed.
     
  12. >> It is neither magnetic nor optical but electrical<<
    I have not a clue as to what 'flash' means and it seems a sophistication to divorce magnetism from electricity since we use direct current in our cameras and in my limited experience of model railways you need magnetism to make them work with DC ... all far beyond me :)
     

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