How to Choose an SD Card for Your Camera

Choose an SD Card Image

A memory card used to be a set-and-forget type item in my camera kit. Buy once, plug in and use, then only worry about it once I need more capacity, right? Well, it started to become a concern a few camera upgrades back— with more consideration for multiple card slots in a camera, how much 4K and HD video I could cram in a card, read and write speeds… and the list went on.

Choosing the right memory card, especially with secure digital (SD) cards, doesn’t have to be a complicated affair, but nailing down the main points of criteria is going to be helpful in the long run. Here’s some advice to choose an SD card for your camera.

Along with most DSLR cameras, many devices including smartphones, laptops, and tablets, use SD cards. And they all require different sizes and capacities. So, to make it easier, we will cover here the main considerations to help you choose an SD card for your needs.


SD cards, especially those used for cameras, need to be considered from their speed performance. Basically, SD cards read and write at different speeds depending on which you buy. Which speeds you choose will really depend on your usage.

If you’re firing off lots of photos in quick succession, you will need a fast write speed. The same goes for high-resolution video. If you’re only taking a few images here and there, then you can get away with slower write speeds. The faster the read and write speeds, the more expensive the SD card, as with capacity.

Choose an SD Card Image 2

The SD Association has different class guidelines for different speeds of SD cards. There are four different speed Classes: 10, 6, 4 and 2. Class 10 is the fastest (up to 80MB/s), while Class 1 the slowest. These are the maximum write speeds, which you may not always achieve depending on your device and circumstances.

The different classes will be shown on an SD card as a number inside a C symbol. You might also see something like ‘533x’ written on a card which denotes multiple speeds of a CD (150KB/s). In this case, ‘533x’ is equivalent to 80MB/s.

Choose an SD Card Image 3

UHS speeds are also quoted on certain SD cards. This rating came about due to higher speeds needed for 4K video. There are two classes: Class 1 and 3. Class 1 has a minimum 10MB/s write speed, while Class 3 starts at 30MB/s write speed. You can spot this on a card as a number inside a ‘U’. UHS bus speeds may also be quoted as either UHS-I or UHS-II. These have different read speeds with UHS-I having 104MB/s, with UHS-II having 312MB/s.

Which speed SD card should you buy? As above, it will depend on your usage. Class 4 or 6 is fine for a smartphone or sporadic camera usage. If you shoot stills or video on a regular basis, then Class 10 is the best way to go.

Physical Size

SD cards come in different physical sizes. Standard SD cards are the norm for most digital cameras, then there are miniSD cards and microSD cards. Standard SD cards measure 32x24x2.1 mm, with the identifiable cut corner design. The ‘mini’ or ‘micro’ cards are mostly in the realm of consumer devices, so we will focus on the standard SD card here.

Whichever camera you own, the SD card slot will only fit a standard SD card, but there are options for adapters. These are the size of a standard SD card, which you can fit one of the microSD cards into. Thus, you can use a micro card in a standard slot.

This can also be done with older DSLRs which have the larger CF cards which can be bought as an adapter to fit into it a standard SD card. In other words, there are options to use a standard SD card on nearly all digital cameras.

Storage Capacity

Memory card capacities are the numbers we are most familiar with. Just like hard drives and USB drives, SD cards can have a wide range of storage capacity. Just like with Classes, an SD card can show some numbers and symbols to tell you its storage capacity. SD Standard Capacity (SDSC) cards range from 1MB to 2GB. SD High Capacity (SDHC) cards are in the range of 2GB to 32GB, with SD Extended Capacity (SDXC) cards having 32GB to 2TB.

It’s not just about buying the largest capacity cards and job done. You have to make sure your reading and writing device support these formats, most importantly SDHC or SDXC cards. The latest crop of SD cards are mostly SDHC, witht the higher spec SDXC cards being less numerous.


You only need to do a quick Google search to find the vast amount of SD cards available. Even with standard SD cards, competition is fierce and with every year that passes, you get more speed and higher capacity for your money. Paying just that little bit more for more speed and extra capacity is worth it in the long run. With camera memory cards, it’s always better to have too many than too few.

To be on the safe side, I always stick with well-known and trusted makes. Yes, they cost a little more, but it’s having the peace of mind that they work, time after time. Some of the brand leaders include SanDisk, Kingston, Samsung, and Sony. There are many others, such as ProGrade, which have very high write speeds, but personally, you can’t go wrong with SanDisk’s line of ‘Extreme Pro’ SD cards as general, all-round, workhorse memory cards.

How to Choose an SD Card

When buying SD cards, you always need to check the symbols on the card, then make sure your devices support a certain card. That goes for both your reading and writing devices. Always check the manufacturer’s documentation for which memory cards are supported. This may take a little reading of the manuals, but it will be well worth it. Learning the different criteria of SD cards will enable you to identify the different speeds and capacities on a whim.

Just follow some of the naming conventions above and what is allowed on your individual devices to easily navigate the SD card world.

Leave a Reply

Your email address will not be published. Required fields are marked *