What Class Rating For A Memory Card Should I Choose ?

Understanding memory card class rating is relatively simple if you follow the guidelines that are recommended to you by your camera or camcorder's manufacturer. Confusion may arise when your equipment has been on the market for a few years and a new model of memory card becomes available. Often the question is should you buy into the new class rating and new memory tech? 

Since the 1990's there have been several new releases beginning with SD, through to SDHC and SDXC and latterly the additional UHS-1 and UHS-3. Each pushing the boundaries of official memory card class rating both in read and write speed and megabyte capacity. 

The market was becoming so advanced at such a fast rate that the Secure Digital Association released updated class rating charts in both 2008 and 2009 so consumers could measure the minimum standards they could come to expect from such memory storage devices. 

Where Do I Begin With Memory Card Class Ratings? 

There may well be two sets of numbers and lettering on any one memory card. Both of these allow you to understand the limits and minimums of a card's performance. A class rating is the worldwide standard for gauging minimum write speeds. You may also notice a UHS class speed rating. This is a separate rating which advises for use with UHS compatible devices (Ultra High Speed). 

Below you will find two charts, the first shows the current SDHC class rating chart, the symbol is shown in a broken circle and advises of the minimum write speed. The second shows the UHS speed class rating within a U shape. The latest and fastest memory card technology specifically for video recording. 

Compare Memory Card SDHC Class Rating Chart  Compare Memory Card UHS Speed Class Rating Chart 

Is There a Difference Between SD SDHC SDXC And UHS Speed Class Rating? 

Yes there absolutely is a difference between these four types of memory card rating, which is what makes the class rating even more useful. If you were to buy the latest camera or camcorder on the market, it will most likely be compatible with SDXC and or UHS-1 speed. 

However for older equipment you will need to turn to your manufacturer guidance and labelling to understand which memory cards will work to its fullest capability. 

A simple way of remembering which card's class rating will suit your equipment is this. Your photographic or video recording equipment will have a minimum recommendation. SD, SDHC or SDXC. Each will accept the equal card or former technology but not the latest. For instance an SDHC enabled camera will accept both SDHC and SD but not SDXC. 

What About My Camera Or Camcorder's Class Rating? 

Read and write speeds, as any professional photographer will know, are very important. If you are shooting on continuous burst or recording high quality video you wish to ensure every snap and stream is saved correctly. Class rating does not affect the quality of picture taken, simply the speed of saving and safety in memory storage at speed. 

While you do need to take note of the SD, SDHC and SDXC compatibility, you also need to refer to the aforementioned diagram and ensure your speed is compatible also for your usage. Check your equipment for the class rating 2, 4, 6 or 10 and buy the appropriate card. 

While all class of cards will work in the respective SD category, you will see faster performance from a higher class rating of memory card. Shooting at twenty frames per second with a 10mb card is far superior to use than that of a write rate of 2MB/s. 

So if your query is what class rating for a memory card should I choose? Follow these very simple steps and compare them to our catalogue of memory cards. 

- Check equipment guidance for SD, SDHC and SDXC 
- Ultra High Speed (UHS) equipment will work best with UHS rated memory cards. 
- Your usage as a photographer may be best suited to higher MB speed if shooting on continuous burst. 
- However a lower class may suit most people.