In ancient times, when movies and music were stored on tapes and computers used floppy disks, we were told that magnets were basically the devil. Even watching VHS tapes over and over would eventually cause them to lose all their information. That’s because the tape and the disks themselves were magnetic. That’s how the data was stored.
Now, though, this old warning has become a modern-day myth with the digital memory cards we use in our DSLRs and mirrorless cameras today. But it turns out that no, magnets will have zero effect on your memory cards – even REALLY powerful ones, as proven by Braniac75.
The above video was actually posted last year, but it popped up on my suggested feed last night and I had a goo watch. Our host walks us through his process for testing, which involves placing files on a PNY 32GB microSD card, creating MD5 checksums from them and then subjecting the card to various levels of magnetic torture to see if it has any effect on files at all.
And surprise, surprise… Nope, not a thing. Throughout the entire card, even using magnets so strong that they literally have a warning label that shows somebody’s hand being crushed between two of them. Oh yes, and one of the strongest AC electromagnets out there – one that many of us deail with on a daily basis – an induction hob.
Braniac75 has also done similar tests in the past with mechanical hard drives which resulted in a physical failure of the drive, as well as SSDs that like the microSD card came out the other side completely unscathed.
I hear the memory card magnet myth posted at least once or twice a week in Facebook groups, and I always have to laugh because there are quite a few memory card readers out there that are magnetic themselves, in order to be able to stick them to your computer case or stack them or whatever. I’ve got two of them stuck to the side of my metal PC case right now (the ProGrade CFast/SD and the ProGrade dual microSD readers).
I think if there was an issue with magnets, the memory card manufacturers wouldn’t be sticking them into their card readers.
The X-Ray thing also seems to have passed along from the film days into digital myth, too, but no. X-Rays won’t kill your memory cards, either.