Last month, while preparing for my Kelby Training class on the Canon 60D, I experienced a little frustration while testing out the video recording functions. Things were going along just fine when all of a sudden, my camera stopped recording and posted a message on the rear LCD that told me that the video recording was automatically stopped. I thought perhaps I was doing something wrong and checked all of my recording settings and tried again. I got similar results over and over again.
I started scouring the Owner’s Manual for a hint at what might cause this problem and found the following on page 297 –
I certainly hadn’t recorded long enough to reach the 4GB file size so my only other option was the speed of my SD card. I pulled out my card, a Kingston 16GB SDHC Class 6 card, just to verify that it met the minimum specs and from all indications it did. The card was also fairly new and had been formatted in the camera.
Just to be sure, I replaced the card with a second Kingston card with the same stats as my first card just to make sure that the first card wasn’t suffering some sort of problem. I fired up the camera, started the video recording, and once again the camera stopped recording on its own. This was a little surprising so I grabbed a SanDisk 8GB SDHC Class 10 card and tried to record some video. Sure enough, it recorded without any problems.
So what does this tell me? Well, I guess it’s that all SD cards are not created equally and speed recommendations are just that, recommendations. Now I’m not saying that Kingston cards aren’t any good. In fact I have had no problems shooting still images with with the two 16GB cards that I have. I think though that the problem lies in the actual write speed of the card. The class rating of the card is usually listed on the front of the card (it’s that number inside the circular C). A class 2 card has write speeds of at least 2 MB/s, while a class 6 is a minimum of 6MB/s and 10 MB/s for a class 10 card. The ratings are based on the least sustained write speeds for a card in a fragmented state but they can be faster than the rating. So, while my Kingston cards met the recommended speed rating of 6 MB/s, I couldn’t get consistent performance until I switched to the faster class 10 card.
It’s always a good idea to use a major brand of SD card to ensure your image integrity. I typically shoot SanDisk cards and have never suffered a failure (knock wood). Now that I am shooting a little more video, I guess I have to consider my speed rating as well to ensure that I am getting consistent video recording with as few dropped frames as possible. My final advice is to test your cards before you need them. Just because they supposedly meet the manufacturers recommendations doesn’t mean that they will perform they way you need them to.