strong magnetic field concerns

M

markfpv

Veteran
Hello - looking for any advice / info from anyone who might have experience shooting around strong magnetic fields. Is this a cause for concern when using a modern digital cinema camera?
I have seen first hand the strange behavior a powerful magnetic field can have on electronic lenses (many years ago was shooting with the HVX200a and all focus operation became inoperable) but I'm wondering if there may be other possible effects to internal parts to camera and/or lens? TIA
 
You might want to stick to manual focus lenses (and more plasticy ones... this is an area the Rokinons would have a strength! :-P ha).
 
I don't have experience, but it can't be good. It depends on what kind of magnetic field (steady state or changing) and what strong means (like MRI strong?). At the very least, a really strong steady state magnetic field will magnetize any ferrous metal parts of the lens and camera. It could ruin any motors of the lenses by ruining the magnets. If it is a changing magnetic field, it can wreak havoc to the electronics as a strong field will induce currents in any conductors. If it's MRI strong, well, you heard about the guy that was recently killed because he was moving a gas cylinder into an MRI room when the MRI was on.
 
Thanks for replies. This is in an industrial setting - molten aluminum - so not an MRI situation but certainly a dangerous area. Lots of electrical current being used to create an electrochemical process. Folks with pacemakers are not allowed in the area and it is recommended not to take credit cards - because the magnetic strip on the cards can be erased (or perhaps altered is a better explanation). Also wind up watches can be ruined.
I have been and shot in the area before. And years ago - back in the Betacam days - the company actually had some type of camera "cage" built for an internal dept to be able to shoot beta tape in this area. In past experience, the HVX200 (theirs) would work fine - and then suddenly the lens would go bonkers & manual focus would no longer work. Moving further away from production area (sometimes just a few feet) would then "fix" the problem - allowing focus again. Even though it wasn't turned on in the menu, I assumed this was the OIS in that fixed lens camera getting magnetized (if your familiar with the HVX200 - you can hear the OIS mechanism rolling around internally when turning the camera over in your hand.) And their camera was still functional & the P2 media seemed to have no issues. But certainly don't want to jeopardize any of my equipment with an invisible "attack" just for getting a few feet too close.
 
This sounds like a scenario where I'd want to take a "cheap" camera (but still decent ish quality, such as say a Panasonic G7 which can be picked up for US$300ish secondhand?!) with a lens that isn't likely to fail (so no AF lenses! MF only. And no OIS).

That way in worst case scenario and your gear gets fvcked then at least you're not out of pocket by too much.

I'd probably bring along a spare back up camera in the truck too, just in case. Even if it is say just a lowly Panasonic GH1 you picked up for less than a hundred bucks.
 
If this is your gear and the client is asking you to go into this environment that could potentially damage your equipment, I would get something signed making them financially responsible for replacement or repair of anything that may get damaged. About a year and a half ago a client wanted us to mic-up a football player during a college game for a feature. I told him we would IF they agreed to pay for the transmitter and mic if anything happened. He ran it by his bosses and agreed. Fortunately the equipment was safe and sound at the end of the day and my audio guy got great audio.
 
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