SD, SDHC, SDXC cards… What’s the difference?

Everybody’s familiar with the SD card. If you have a digital camera then most likely you’ve encountered what an SD card looks like. But do you know what’s the difference between SD, SDHC and SDXC cards?

I have to admit that I had to google it up when I got curious and the answer is pretty simple. Capacity. SD was the first of its kind before GBs of data can be stored in its compact size. SDHC means high-capacity while SDXC is extended capacity. But at what capacity would you classify if it’s SD, SDHC and SDXC?

Although it shouldn’t really matter to most people, here’s how you classify each type of SD card based on capacity:

  • SD – 1MB to 2GB
  • SDHC – 4GB to 32GB
  • SDXC – >32GB to 2TB
Don’t be fooled with the 2TB on an SDXC, it’s only theoretical based on its data structure. The largest SDXC in the market at the moment is a 128GB one and also a Class 10 card.

Bonus: What does Class on an SD card mean?

You’ve probably seen a number on the sticker on your SD card. It can be a 2, 4, 6, or 10. So what does these numbers mean?
These numbers denote the Class of the SD card which represents its transfer speed. The higher the number, the faster the transfer speed.
So for Class 2 it’s 2MB/sec, Class 4 it’s 4MB/sec and so on. Note that there’s no Class 8. Typically Class 4 is sufficient for photography unless you’re shooting in RAW. You will notice a slight delay in taking the next shot when you’re on Class 4. For video recording, you will notice a shorter allowed time per clip when using lower class SD cards especially if you’re shooting in high definition. Class 6 or better yet, Class 10, should be used when you want to capture long high-definition videos.
Now there’s a new Speed Class called UHS which means ultra-high speed and are more geared towards professional videographers. The number you would probably see on the sticker is 1 but it simply means it’s UHS which is capable of 45MB/sec transfer speed. These babies cost around $140 a pop.

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