Every letter and mark on a camera’s memory card has meaning. Which cards are worth the price? Do I even care?
The answer to the last question should be YES. Here are a few links to help you sort it out, along with my reader’s digest version below.
The super-basics are laid out by CNET, one of my favorite sites for reviewing and explaining gadgets.
The SD Association has a technical but informative website about the types of SD (Secure Digital) cards and their meanings. I’m impressed that the SD Association even exists.
Jenna Gregory wrote a great article for What Digital Camera about choosing memory cards. Again, it’s pretty detailed, but it’s a strangely complex subject.
1. Determine what shape and type of memory card fits into your camera. Examples are SD, CF, SDHC and SDXC. As of this writing, SDHC is the most common.
2. Find out what speed and type of memory card your camera will handle. If you get a card that processes data faster than your camera does, you’re not getting the benefit of the extra speed you just bought. The card will work, but not at the advertised speed. For instance, highly-marketed UDMA cards and UHS cards only achieve maximum speeds with UDMA or UHS cameras, respectively. The fastest speeds are usually designed with video in mind.
3. The speed you need depends somewhat on your usage. For instance, you definitely want to invest in high write speeds if you’re shooting video or sports. Of course, you pay more for top speed.
4. Reading speed is how long it takes information to get off the card and onto your computer or device. It’s usually slower than the write speed. For photographers who work on deadline, this can be a critical issue.
5. Be sure to you have a card reader optimized for your card and a cable that doesn’t slow down your data transfer. If you get new memory cards, you may need to upgrade your card reader, too.
6. Care for your cards by formatting them occasionally. Personally, I format cards each time I erase them clean.
7. Always have a backup. This includes multiple memory cards on assignment.
In the photo example of the SanDisk Extreme Pro card, it is an SDXC-I card that holds 64 GB of data. It’s maximum burst speed for writing files from a camera is 95 MB/s.
The 10 in a circle means the Speed Class is 10. This certifies that read and write speeds won’t drop below a minimum (as opposed to the advertised maximum burst speed) on any camera. A standard consistent speed is good for things like making video run smoothly.