When buying a memory card you might come across a whole host of different memory card types and sizes. And like most people, you might ask yourself, &ldquo;what does this all mean?&rdquo; Read on and let us help you clear up the confusion.

The SD Association is an organization that dictates standards for memory cards. Currently, memory cards are classified into three general categories: SD, miniSD, and microSD. In recent years, microSD cards have become the most widely used of the three due to their use in smartphones, DSLRs, dashcams, action cameras, etc. miniSD cards are less common these days and only used in older devices such as PDAs. SD cards are most frequency used in digital cameras and camcorders.

Card Types

Figure 1 : Card Types

Memory card capacity can be classified into four different standards: SD, SDHC (SD High Capacity), SDXC (SD Extended Capacity), and SDUC (SD Ultra Capacity). The supported capacity ranges are shown in Figure 2. Then there is the FAT file system: FAT16, FAT32, exFAT. Both Windows and macOS support FAT files, however it should be noted that FAT32 file sizes are limited to 4GB. In order to meet the needs of today&rsquo;s high-quality audio and video, exFAT was created. exFAT files are compatible with Windows 7, mac OS X 10.6.5 and above.

Capacity and Compatibility

Figure 2 : Capacity Comparison

Figure 3 : Capacity and Files Supported

For example, if all your photos were 14 mega-pixels, 2GB would allow you to store approximately 340 pictures, and 32GB about 5,400 pictures. Based on a standard Full HD video, 2GB could store approximately 20 minutes of footage, while 32GB about 5 hours, and 2TB about 300 hours. Do also note that some cameras may have a limit for capacities supported. For example, some actions cameras only support memory cards of up to 32GB!

Figure 4 : Choosing a Suitable Capacity

There are three general speed classes - Speed Class, Ultra-High Speed (UHS Speed Class), and Video Speed Class (Video Speed Class). These classifications are followed with either the letters "C", "U", and "V" to and numbers indicate the minimum per second, read/write speed of the card. The higher the number, the better the writing performance.
Regarding smartphones, more specifically app usage, there are two types of cards designed for this purpose. These cards are defined via the Application Performance Class classification as either A1 or A2 cards. A2 cards are capable of processing more data than an A1 card can in the same amount of time. So, if you&rsquo;re a heavy app user an A2 card is what you want.

Speed Class

Figure 5 : Speed Class and Applicability

&ldquo;As all three standards support a write speed of 10MB/s, what is the right one for me?&rdquo; you might ask. At the end of the day, it is more important to consider what you are using the cards for. For example, if for photography a C10 card is sufficient for your needs. For creating high-res videos U1 and V10 cards are best because if the minimum writing speed of the memory card is lower than the speed at which the video is processed, the video will not be smooth.

When buying a memory card you might come across a whole host of different memory card types and sizes. And like most people, you might ask yourself, “what does this all mean?” Read on and let us help you clear up the confusion.