Everyday somebody complains, on one of the many forums, about problems with their memory card be it Compact Flash, CF, or Secure Digital, SD, card. And the standard answer is: “Reformat card in the camera after every upload to your computer”.
There are so many misconceptions, so at great personal expense, I had to call the “Debunking Unit”. Those guys don’t come cheap.
Problem 1: The memory card wears out
- Yes, the memory card has a fixed number of read and writes, after that it will die.
- Memory cards are rated for a number of read/write cycles. Not reads, not writes. In the old days, the 90s, the Compact Flash and SD cards were usually rated in the tens of thousand of read/write cycles.
- Today memory cards are rated in the millions of read/write cycles. Sandisk rates their “pro” cards at 2 million read/write cycles.
- When a company rates their card at 2 million read/write cycles, it’s the minimum amount of read/write cycles that is guaranteed. That’s the minimum number of cycles. Usually the memory card should last for at least 30% more. That’s the engineers’ way of covering their ass.
- Please also note that it’s a cycle of a read followed by a write. But that’s not how we use the cameras. Most of the time, we do writes on the camera, unless we review the photos and do a slide show on the LCD. Most of the time we do reads on the computer. How does this affect the life expectancy of the memory card? Can’t find anything published.
Problem 2: Do you need to reformat your card after transferring the photos?
No, but it’s easier. The major problem is when people delete the photos from the card while connected to the computer and they also delete the important directories like DCIM and the camera such as 100CANON.
- By the way, reformatting does not erase the photos. It only erases the existing directories, the directory entries and re-creates the new directories of DCIM and the camera such as 100CANON.
- The photos are still on the memory card and have been flagged as deleted so the space will be available when needed. That’s why you can have “rescue” software.
Problem 3: The memory card wears out, again
Yes, memory cards wear out, but you said no in the #1. The part that wears out is the contact grid of the memory card.
- Transcend rates their cards at 10,000 insertion/removal cycles
- Sandisk rates their cards at 10,000 insertion/removal cycles
- Lexar rates their cards at 10,000 insertion/removal cycles
To see the exact amount for insertion/removal cycles, go to the technical specs for your memory card. The current standard is 10,000 insertion/removal cycles but there are significant variations, even within manufacturers.
- When a company rates their card at 10,000 insertion/removal cycles, it’s the minimum amount of insertion/removal cycles that is guarantied. That’s the minimum number of cycles. Usually the memory card should last for at least 30% more. That’s the engineers’ way of covering their ass.
- An insertion/removal cycle is a when inserting the memory card in the camera, and pulling it out. The next cycle is to do it again into the card reader connected to your computer.