Originally posted by Yamanobori I am not sure the card will make a big difference in the write speed.
I set the card slots to copy each image to both cards. I simply use the PNY Professional line and have two sets of two cards for shooting. That is simply the backup I have in the field. I have never tried to copy from one card to another. I think it is simply easier to make a backup when I shoot. The PNY cards are not that expensive and seem to be reliable.
Will copying to both cards at once cause a significant slowing in the review speed? In most cases it's not a big deal, but sometimes when the light is changing quickly, it's nice to be able to make a quick review of the histogram and adjust accordingly...before clouds move too much or light changes, in the case I'm considering an HDR afterwards, or manual blending of images.