If you ever tried shooting a video with your shiny new Canon / Nikon DSLR only to find out that on recording @ 1080p or 720p resolutions the camera stops recording automatically after few seconds & you are thinking that it’s some defect in your new DSLR then put your disappointment to some rest as this might not be the case in at least 99% situations , this happened with me too and my first reaction was what the hell !! I paid 36K indian rupees (~700$) for a camera that cant even record me good quality HD video while my older Nikon P100 was doing it flawlessly , then as my disappointment calmed down and i did some google searches to find out that it was in fact the memory card that was the culprit .
SD memory cards which we generally get for free with our DSLR’s are of class 4 rating and the cheapest ones right now on the market , for those who are wondering what does class4 means , well to put it simply “If you need to shoot HD videos with your DSLR buy SD cards with rating of a minimum of Class 6 and Recommended would be Class 10″ , so all those who are suffering from this problem just head straight to your nearest camera shop (Computer goods people generally dont keep higher rated speed cards as they sell less in volumes & 90% of people dont know what is a speed rating yet ) and ask for a class 10 SD card and if you are a little low on budget even then I will recommend you to get a Class 6 card and porbably a Transcend / Sandisk one !
You can see here that Canon recommends a minimum of Class 6 too and even though these cards flaunt speeds of upto 30MB/sec but that is reading speed and for Video recording you’ll need a higher write speed , at least 10MB/sec .
You can read more about card speeds and ratings at Wikipedia .
also, if you are looking forward to buy such card then I’ll recommend this deal specially for Indians as you wont get a class 10 card cheaper than this and that too from likes of Transcend, Flipkart is giving a transcend Class 10 16Gb card for around 895 rupees which i ordered just today ! Go buy yourself one and happy Video shooting!