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Impact of a magnet on the A7RII

A7RII image stabilization

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#1 svilla

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Posted 15 March 2017 - 05:54 PM

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I have read that the A7rii uses magnets for its image stabilization feature.  I have the MagMount system that features a very strong rare-earth magnet to allow you to quickly mount and dismount your camera. It actually worked pretty good with my other camera but I have been a little worried using it on my A7rii. I only use this on my walking stick for additional stability when I am hiking around and not on my tripod. Here is a link to the page (TechTrek Mag Mount) if you need more info on the camera mount system. 

 

Will this mount damage or cause issues with my camera? I am just worried about the magnet somehow messing up the image stabilization.

 

Thanks



#2 Jaf-Photo

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Posted 15 March 2017 - 07:42 PM

Keep magnets away from cameras and lenses. They contain metal parts and rely on magnetism to work.

#3 Username

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Posted 18 March 2017 - 12:36 AM

When the camera mounts to the magnetic receiver, the matching 

piece in the camera's tripod hole acts as the magnet's keeper, so 

the magnetism is contained in a "closed loop". Nothing to worry 

about. Also, magnetism from an "open" magnet [no keeper on it] 

falls off absurdly fast at even a very small distance from the pole, 

so again, no worry. But you wouldn't want the open magnet in the 

socket of the quick-mount to be laying right against the camera 

body when in storage or transport .... a reasonably easy situation

to avoid ;-)  

  

And oh, yeah, stay away from the tinfoil hat crowd. 



#4 svilla

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Posted 20 March 2017 - 12:26 PM

Thank You



#5 tinplater

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Posted 20 March 2017 - 01:56 PM

I had same concern about magnets in a Think Tank 20 Mirrorless bag.I experimented with cards, cameras, lenses, cell phones, and was unable to identify any issues.I even left my phone and cards with images on them next to the magnets for over 24 hours with no ill effects.Additional research failed to identify any issues that I could find on the net.



#6 SimonT

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Posted 12 May 2017 - 07:28 AM

I would not trust this device close to any cards including credit cards! It's your risk but rare earth magnets are very strong. I have no connection with that manufacturer but I do hold 4 patents covering a completely different product but using similar magnets. Jaf-Photo's comments are equally valid. Another poster's comment that he suffered no damage should be viewed cautiously. No mention was made regarding the 'distance from' and the 'angle to' the magnet field, all of which are important criteria. Attractive as it sounds, knowing what I do, I would not use this.


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#7 Jaf-Photo

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Posted 12 May 2017 - 12:28 PM

Thanks. People who play with magnets may be lucky. But if they end up in the wrong place, they could seriously mess with electronic or mechanical devices (cameras are both). I've personally ruined a TV set with a strong magnet (damn that curiosity). So why take the risk?

#8 tinplater

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Posted 12 May 2017 - 01:11 PM

Now two months later, no issues whatsoever with the magnets added to my Think Tank bag (which already uses magnet closure). It has made the bag much more secure against against accidental opening.



#9 SimonT

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Posted 12 May 2017 - 01:49 PM

A magnet for holding an SLR is much stronger than the smaller size needed to keep a bag closed. Still they caused havoc with credit cards when fixed to ladies purses. That was 20 years ago before the stronger Neodymium magnets were commonly available. It's difficult to outline all parameters and circumstances and it also depends on the design of the magnet. I have no axe to grind and will rest my case. I just advise the user to beware.



#10 Username

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Posted 13 May 2017 - 07:05 PM

Flash memory is not magnetic memory and is 

not affected by magnets. This covers your SD 

card and your firmware. The vulnerability issue 

is with the actual electro-mechanical devices of 

which there are many inside your gear. Keep 

the naked magnetic "grabber" side of the quick 

connect away from your gear during transport. 

 

 

------------------------------------------------------------   

 

  

As to magnetic closures for bag flaps, popular

powerful disc magnets should not be stitched

into flaps as-is. The emanate a powerful field

from both of their flat surfaces. It is safer to 

create  magnet that emanates a powerful field 

from only one side, IOW only in one direction. 

 

The proper precaution is to set two discs onto 

a strip of steel, where they will cling, but epoxy 

them anyway. Set them with opposite polarities. 

The strip of steel is their keeper on one side but 

the other side has a powerful field. Stitch this 

assembly into the bag with the field pointing out 

and away from the interior of the bag. A steel 

strip stitched into the flap will cling to the hidden 

outward-facing magnets.   

 

Placing magnets with mutually opposite polarity 

on the strip will provide a tighter grasp on the 

steel-loaded flap vs having both magnets facing 

the same way. This allows you to use weaker 

smaller magnets yet still have a powerful hold  

for keeping the flap closed. Opposing polarities 

also bend much of the magnetic field into an arc 

between the N-pole of one disc and S-pole of its 

partner. If both discs were mounted with to the 

strip with like polarities,the field would not arch 

but would emanate straight out from the open 

["unkept"] side of the pair of discs.  

  

Essentially, adhering the pair of discs to their 

steel strip at opposite polarities creates a horse 

shoe magnet. OTOH, adhered with like polarity

you have bar magnet. Despite lacking the horse

shoe shape, or bar shape, Very importantly for

safety, the shapes of their fields will be as per

those horse shoe or bar magnet shapes. 





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