SD Cards 101

How to Choose the Right SD Card? 

SD Cards or Secure Digital memory cards, as they are also known as, are stamp-sized flash memory devices which have become common place. I'm sure most of us who use digital cameras, camcorders, or smartphones, have seen these memory storage devices at some point or another.

If you look at the image to the left, you will notice that they look quite similar to each other at first glance. However, it can be confusing to understand what the different specifications mean. For example, what do these specifications "Transcend 32 GB Class 10 SDHC Flash Memory Card" mean? And how do these specifications compare with the SanDisk product "SanDisk 16 GB Class 4 SDHC Flash Memory Card"?

Other common questions that arise are How do I choose the right memory card for my digital camera?; Can I use the same one in my digital camera, video camera, and smartphone?; What are the different types of Secure Digital cards?; and so on. Well, it can be confusing when you examine the detailed specifications, classes, and sizes. However, I'm going to make this simple and hopefully help demystify Secure Digital memory cards for you.

SanDisk SD Memory Cards 

These SanDisk Secure Digital memory cards featured above are standard and high capacity SDHC. They can be used in digital devices like digital camera, video recorders, laptops, computers, video gaming systems, and other digital devices. There are memory cards that have faster writing speeds called UHS (Ultra-High Speed) Secure Digital cards. You can find these memory devices further down this web page. Also, refer to the section below, on how to choose the right one for your digital devices

SD Card 101:  Understanding Secure Digital Card Basics

 

As mentioned earlier, Secure Digital cards are compact memory storage devices that can be used in digital cameras, laptops, computers, tablets, smartphones, video gaming systems, and other digital devices. They help store data like pictures, videos, movies, music, apps, and other types of digital files.

There are many different types in the market today for various digital devices, so it’s important to choose the right one for your device(s). Several companies like SanDisk, Kingston, Transcend, Panasonic, Sony, Kodak and Lexar, manufacture various types. In order to set industry standards for Secure Digital card specifications, the SD Association was established in the year 2000.

Understanding specifications can be confusing, but I’m going to keep it simple and focus on three main aspects. This will help you differentiate between various types and guide you on how to choose the right one for your digital devices. These three main aspects of Secure Digital cards are: the size, the speed class, and the memory capacity:

SD Card Size: They generally comes in three different sizes. As you can see from the image above, the standard size SD card, the miniSD card, and the microSD card. The Standard size is the most common format and widely used in digital cameras, camcorders, laptops, computers, and printers. The miniSD size were used in mobile phones, but in the past few years, we’ve seen less of them and more of microSD cards. The microSD card is mostly used smartphones and tablets, but can also be used (with an adapter) in digital cameras, camcorders, computers, printers. In summary, you would generally be using the Standard sized one or the microSD card for your digital devices.

SD Card Speed Class: is the next important aspect of Secure Digital device specifications. The speed class determines the minimum data writing speed or the rate of speed at which data is transferred to the memory device. This speed is calculated in MB/s or MBps which translates to “megabytes per second”. As you can see in the above image, there are four class speeds namely Class 2, 4, 6, and 10, and one UHS (Ultra-High Speed) class. A Class 2 speed has a minimum write speed of 2 MB/s, a Class 4 speed has a minimum write speed of 4 MB/s, and so on. UHS class SD cards are identified with a “U” with a number in it. Currently, only UHS-I SD cards are available and have maximum write speeds of 104 MB/s. And UHS-II SD ones are expected to have write speeds of up to 312 MB/s.

SD Card Memory Capacity: determines the memory storage capacity of Secure Digital cards. The capacity of these memory storage devices is broken down into three main groups (as shown in the above image): namely, Standard SD which stores up to 2GB of data; SDHC (High Capacity) which has memory capacity between 4GB and 32GB; and SDXC (Extended Capacity) which has memory capacity between 32GB and 2TB.

All the above specifications appear on the Secure Digital device itself as you would have already noticed on the images earlier. Now that you’ve mastered the basics of three important aspects of SD card specifications, let’s learn how to use these specifications to help us choose the right one for our digital devices. Before we do that though, you may want to take a quick peek at the video below explaining different types of Secure Digital cards.

Video Review of Different Types of Memory Cards 

This helpful video tutorial below will help you understand the different aspects and specifications of SD memory cards. It covers the basic specifications, as I covered in the previous section, but also covers some important information to help you choose the right one for your digital devices. It also shows how to use Secure Digital device adapters with miniSD and microSD cards. Furthermore, it covers the compatibility aspect of various memory cards and digital devices. In the video, you will also see a speed test showing the rate of speed at which different classes of Secure Digital cards write data.

SanDisk UHS-I SD Cards 

 

UHS Class SD memory devices are Ultra-High Speed SD cards with write speeds up to 312 MB/s . UHS Class SD cards are identified with a “U” with a number in it. At the present time, only the UHS-I ones are available and have maximum write speeds of 104 MB/s, whereas the UHS-II Secure Digital cards are expected to have write speeds of up to 312 MB/s. On UHS Class ones the maximum speed is labeled on the front of the cards as shown in the above image.

For example, the SanDisk Extreme 8GB SD memory card above has a maximum write speed of 30MB/s, whereas the rest of the UHS-I ones above have a maximum write speed of 45MB/s. Also, if you notice, they come in SDHC and SDXC formats. UHS Class ones are backward compatible and can be used with SDHC and SDXC format SD cards. Due to the high write speed of UHS memory cards, they are ideal for Full HD video recording and continuous high-resolution still photography.

Eye-Fi Wireless SD Memory Cards 

 

Eye-Fi SD cards are innovative memory storage devices that are Wi-Fi enabled, allowing pictures and videos to be automatically transferred to other Wi-Fi connected devices like laptops, computers, tablets, or smartphones. It also allows you to automatically share your photos and videos on social media sites like Facebook, Twitter, YouTube, Flickr, Picasa and others. Currently, there are three types of wireless Secure Digital cards manufactured by Eye-Fi as shown above.

Eye-Fi Pro X2 SD cards comes in two Speed Classes, 16GB Class 10 and 8GB Class 6. The Eye-Fi Pro X2 features uploads of RAW files and geotagging. The Eye-Fi Mobile X2 comes in 8GB Class 6, and the Eye-Fi Connect X2 comes in 4B Class 6. All the above Eye-Fi memory devices have Endless Memory, a feature that allows you to set it up in a way that the card automatically purges content that has been already safely transferred to your devices

SanDisk microSD Memory Cards 

The smallest sized Secure Digital memory devices are the microSD cards and they are mostly used in smartphones due to their tiny size. These microSD cards generally come with an adapter, as you can see in the above image.

These ones, with the adapter, can be used as standard memory cards in digital devices like digital cameras, camcorders, laptops, computers, and other devices. microSD cards come in standard SD, SDHC, SDXC, and UHS-I formats.

The ones featured above can be purchased at Amazon and are only compatible with SDXC-enabled devices in exFAT format per Secure Digital Standard. They are recommended for Android and other smartphones as well as tablets.

How to Choose the Right SD Memory Card? 

 

Now that you’ve mastered the basics of Secure Digital memory cards, let’s use this knowledge to choose the right one for our digital devices. The market is flooded with a variety of memory devices and not all of them are compatible with all digital devices. Many of them are not backward compatible, which means that an SDHC card will not be compatible on a digital device that uses only standard Secure Digital cards. Buying the most expensive or fastest one is not necessarily the best choice. Therefore, it’s important to know how to choose the right one for your digital devices.

The Speed Class and memory capacity plays a big role in terms of the price. The best thing is to check your device’s user manual which will help you determine the right speed class. Generally speaking, Class 2 are best used for standard definition video and still photography; Class 4 and 6 are used in Full HD video recording and continuous still photography; Class 10 are best used for Full HD recording and continuous HD still photography; and finally Ultra-High Speed (UHS Class) are used for capturing Full HD recording and continuous HD still photography with larger file sizes (greater than 4GB) as well as with the potential of recording real-time broadcasts.

For example, I have a Canon PowerShot SX240 HS digital camera which is capable of recording Full HD 1080p video. The Secure Digital memory cards recommended, as per the user’s manual, are SD, SDHC, SDXC. I can use any Speed Class from Class 2 up to Class 10, however, I can’t use UHS (Ultra-High Speed) Class on this camera. Therefore, buying the most expensive and fastest one would be a mistake in this case. Also, worth noting is that microSD cards of similar compatibility will work with an adapter on the Canon PowerShot SX240 HS digital camera.

Search Amazon for SD Cards

In the Search Box below, you can enter the specific search terms of the SD card that you're looking for. This will showcase all the SD cards available on Amazon and you can purchase them directly from Amazon.