I will be leaving soon for 10 days in Iceland on a photo tour. I have the Sony A7r that I have just started using and love it but I don't have a feel for how fast it eats up memory cards. I know it is totally dependent on the size of the card but I am trying to gauge how many I might need for 10 days of shooting. I have a couple of 32 Sandisk now but need to load up. Any suggestions as to size of card and a how many I might need for such a trip. I certainly don't want to run out of cards but don't want to be crazy about it.