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How To Choose The Right SD Card For The Job
The Elements
When purchasing a SD card, you should take into consideration four main factors. Granted, your manual (you know, that thing you tossed in the trash as soon as you unboxed your device) may actually have recommendations as to what kind of card you should get. Even still, it’s good to know about them:
Class
“X” Rating
Storage
Size
There are four different SD card classes that you can buy. You can grab a Class 2, a Class 4, a Class 6, or a Class 10. This class number simply lets you know the minimum write speed of the card. But what is that number? Well, that’s easy. The number of the card denotes the minimum MB/s that the card can write. For instance, a Class 2 writes at 2 MB/s. Furthermore, there are even ultra-high speed (UHS) cards which can transfer anywhere between 50 MB/s to even 312 MB/s and up.
The “x” rating (or x speed) is actually just how many times faster the card writes down information compared to a standard CD-ROM drive. As a note, these drives write data at about 150kB/s (or 1.23Mb/s). For your information, a Class 2 card has an “x” rating of 13x. Why? Well, I prefer to do this math with megabits, but we can see that 13 times 1.23Mb equals 15.99Mb.
Since 8 megabits equals a megabyte, divide the 15.99 by 8, and we get about 2MB. Thus, this is a Class 2 with a 13x rating. (I hope that made sense.)
As a note, some cards will blatantly display the “x” rating and some won’t. Ultimately, you just need to focus on the MB/s. Classes and “x” ratings are just easier ways of explaining it.
how to choose the right sd card
However, there are currently three primary types of cards with different capacities:
SD – Not used as often; can hold up to 2GB
SDHC – The upgrade to the original SD (a.k.a. SD 2.0); can hold up to 32GB
SDXC – The upgrade to the SDXC; can hold up to 2TB
how to choose the right sd memory card
Moving right along, there are actually three different sizes of SD cards that you can choose from:
Standard size (32mm x 24mm)
Mini size (31.5mm x 20mm)
Micro size (11mm x 15mm)
Each of these pertain to the device, and you should be able to tell anyway. Smartphones may use smaller SD cards than cameras, but they are still SD cards, nonetheless.
For video, the SD Association (yeah, that exists) actually has a few recommendations. Here they are:
Class 2 – SD Recording
Class 4, 6 – Full HD Recording
Class 10 – Full HD Recording and HD Still Consecutive Recording
In theory, this should work. However, once again, these are just the minimum requirements. If the camera actually requires a higher “x” rating, then you would be better off purchasing a higher quality card. For instance, if you put a 40x card in a device that requires 50x, the card won’t be able to function properly.
For more articles about memory card and selection, you should check these out:
10 Things To Know About Digital Camera Memory Cards
3 Cool Ways To Use SD Memory Cards
How to Recover Data from a Corrupt Memory Card or USB Drive