But I’m a curious sort. When I see things like SDXC instead of SD and V90 II and U3 I can’t help but ask myself what I know about all this.I’m old enough (“experienced enough” sounds better) to remember when SD cards were introduced just before the turn of the century. While that sounds like they were steam-powered, in reality, it was in 1999 and they were a step up from MultiMediaCards (MMC).
Historically, the form factor of both these cards was a contrast to the existing Compact Flash (CF) cards that were introduced in 1994 and were the go-to card for the growing digital photography market. CF’s were big and bulky, while these new cards were thinner and offered similar speeds and capacities.
SDs were an improvement over MMC cards because they could hold more data and they could move that data faster. There were also differences in that there was a write-protect feature and the electrical contacts were recessed to reduce finger contact.
The “S” in SD stands for “secure.” This meant that a digital rights management system was available. Part of the reason for this was to compete with other proprietary memory cards that could be used as a content delivery platform. The S remains but is usually not applicable to cinematography or photography space.
Let me fast forward to the card I was testing out. It was an SDXC UHS-II Class 10 V90 memory card. That is a mouthful. Let me break it down piece by piece.
SDXC is Secure Digital eXtended Capacity. After SD and before SDXC there was an SDHC card, the HC standing for high capacity. This allowed for storage up to 32 GB, whereas the SDXC can go up to 2 TB.
The early versions of SD allowed for 1 GB to 4 GB depending on the camera, reader and the computer. This made for a bit of confusion when you tried to select a card to use. You might have wanted to buy the largest card, but it was possible it wouldn’t work in your camera.
So, that’s all about the capacity of SD. Next time, the need for speed.