Last weekend I wanted to try some new memory cards in my D7000. I purchased 4 Transcend 8GB Class 10 cards from B&H. I put 2 new ones in and formatted both of them. Went outside and snapped a pic and it said ERR over the cards. (I save a JPEG on each card) So I reformatted and tried again and it then said damaged card. I tried the other 2 with the same results. So, I called B&H to inquire because 4 bad memory cards doesn't sound right to me. After talking to someone in Customer Service he said that the card speeds are too high for the camera. They did an exchange no problem for SanDisk Extreme. Just wondering how the cards write speed would effect the performance like that? I was thinking that by going to the faster write speed I could get my time exposures of light painting to write faster, that's the only reason I tried them. Thanks for any ideas/help!