SD Card Class Rating – Does It Matter?

Many of our friends have asked us for our recommendations on the type of SD card (SD/SDHC/SDXC) that they should purchase for their camera. In today’s post we will introduce you to the different SD card class ratings and help you to understand the differences between the class ratings. At the end of this post, we will also be sharing an interesting video that we came across that highlights the differences of the SD card class ratings.

What is ‘Class Rating’?

There is usually a class rating associated to each and every SD card. If you look at your SD card, the class rating is often depicted by a number in a circle. Nowadays, you can often find Class 4, 6 and 10 SD cards. These class ratings are generally associated to a theoretical read and write speed for the SD card.

Without boring you with the technical mumbo jumbo, generally, the higher the class rating, the faster the read and write capability of the SD card. So in theory, if you are taking a number of consecutive shots on your camera, the SD card with the higher class rating will usually be able to take more shots within the same period of time as it can write data quicker. The same goes for when you are transferring your photos from your camera to your computer. The higher class rating SD cards will outperform a lower class rating SD card as it can read the data faster from the card.

To add to the confusion, Sandisk (a company who makes many of these SD cards) has in the past released a number of different class 10 SD cards with different read and write speeds. For example, their SanDisk Extreme and SanDisk Extreme Pro class 10 cards. So it is important to note that Class 10 SD cards between different brands are sometimes not created equally and they may have different write and read speeds despite sharing the same class rating.

SD Card Class Rating Test Video

We came across this video which performed a number of practical tests on the different classes of SD cards in the camera. All credit goes out to ‘CameraRec Toby’ for the creation of this video. We hope that you will find this educational –

The Result

Based on the tests within the video, it appears that the higher class SD cards (including the SanDisk Pro and SanDisk Extreme Pro) performed much better when it came to shooting and storing Raw file format photos. When shooting in the JPG file format, the test within this video concluded that it did not make much of a difference.

So, if you are currently shooting in the Raw file format, you may benefit from using a higher speed SD card such as the SanDisk Extreme Pro. It boasts an impressive write speed of 95 MB/s. To find out more about this SD card, you can visit Amazon (below) –

We hope this provided you with a good introduction to SD card class ratings. As always, remember to have fun and happy snapping! Amazon currently have some SDHC memory cards on sale – 64% off (One day sale only). So make sure you check them out here –