Everything you need to know about SD cards

Looking to buy an SD card? But which one is right for you? The huge variety in type, write speed, read speed, memory and category, makes it hard to see the woods from the trees when buying an SD card. But don't worry, we're on hand to help you choose! So you won't make a wrong purchase, say one with insufficient storage space or one that isn't recognised.

What is an SD card?

The SD card is the successor to the Multi Media Card, otherwise known as the MMC. SD stands for Secure Digital. In other words, it is a secure memory card. The card works via flash memory. This helps you easily save data and delete individual files. In addition, an SD card features high read and write speeds. As such, this card type has fast become one of the most popular secure memory cards around.

Besides cameras, video cameras and digital photo frames, many more devices require an SD card. Ever-popular demand for these cards has seen an increase in their storage capacity. So, over and above the old 2GB cards there are now cards on the market with a whopping 2TB capacity.

Which SD card should I choose?

You'll find lots of information, besides the memory capacity, listed on the SD card. Such as the card type, write speed, read speed, but also different classes. All this info is key in choosing the right card for you.

Type: SDSC, SDHC and SDXC

First and foremost, you need to determine the type of SD card your device requires. This information can be found in most user manuals and card slots. There are 3 types in total: SDSC, SDHC and SDXC. 

The SDSC (SD Standard Capacity) was the first SD card launched. These are often found in older devices. These cards have a memory capacity of up to 2GB.

The SDHC (SD High Capacity) type has a larger capacity and is usable in most devices (with an 'HC' designation). These cards have a memory capacity ranging between 4GB to 32GB.

The SDXC (SD eXtended Capacity) card has en even bigger capacity, but is only compatible with specific devices, such as higher-end cameras or high resolution cameras. These cards have a memory capacity ranging between 64GB to 2TB (2048GB)

Memory

The worst thing that can happen is that your SD card reaches its capacity too soon. That is why it is important to know roughly how much you'll be able to put onto your card. The amount of GB you need differs per camera (number of megapixels), per photo (JPG or RAW) and per video (HD, Full HD, 4K, etc.).

Speed: read and write speeds

Naturally, you will want evethying to proceed smoothly. Your SD card's speed will play a key role in this. This can be broken down into read and write speed. The read speed tells you how fast photos can be transferred onto another device. The write speed tells you how fast files can be written onto your card. This is the speed you need to take into account when taking photos. This is usually stated on the card in MB per second (MB/s).

Speed classes: UHS and Video

Nowadays, besides being expressed as MB/s, the speed is expressed in different speed classes. To start with, the classification system was expressed in numbers, prefaced by the letter 'C'. For example: Class 2, Class 4, Class 6 and Class 10. Now, all cards come under the speed class 10 (10 MB/s). This is why, over time, two new classes were added: UHS (Ultra High Speed) and Video.

Both UHS (U1 or U3) and Video (V6, V10, V30, V60 or V90) indicate the minimal write speed. As such, classes U1 and V10 are equal to 10MB/s.

Interface: UHS-I or UHS-II

UHS has two classes: U and UHS. When UHS-I (Roman numeral 1) is indicated on the SD card, this saves onto the interface, or the card connection. UHS-I just has a row of connectors. With an UHS-II card there are extra connectors for faster interaction (read and write speeds). The maximum speed of UHS-II cards is therefore higher than that of UHS-I cards. You will discover which interface you need in your device's user manual.

Would you like to find out more about these products? If so, take a look at our memory card selection guide. This will help you quickly and easily find the right memory card for your particular device and requirements.

New innovations

Over and above a whole plethora of new innovations in the field of SD cards and sizes, such as Micro and Mini, new card applications have also been developed in recent years. Wi-Fi SD cards are already available, that let you transfer photos and videos directly to a laptop, Smartphone or hard drive. This lets you instantly share your footage on social media or post a blog.

What brand to choose?

Do you have a particular brand in mind? We have various top brands:

Sandisk | Angelbird | Lexar | Sony | Integral | Peter Hadley | Transcend | Fujifilm