These are images from my G6 and its happening a lot lately. The Jpegs are fine but the many of the raw files have this banding, say 10% of the images that I take. The SD card is Transcend 64 GB SDXC. My workflow is that I shoot images, bring them into lightroom and then format the card in the camera for next time. What is the best/optimal card to purchase to avoid this again (if it is indeed the SD card and not the camera).