Today’s Question: I followed your advice to make use of my camera’s ability to record to two media cards at the same time when capturing photos and videos, so I have a built-in backup. But when I go to format the cards after downloading, I see that significantly more space has been used on one card compared to the other. What is going on here?
Tim’s Quick Answer: Most digital cameras I’m familiar with that offer two media slots are only able to record video to one card at a time. So while you are able to capture still photos to two cards at a time, it is common for video to be only recorded to one of the cards.
More Detail: I am a big fan of cameras with two card slots that include the option to configure the cards for simultaneous recording. This option enables you to have a real-time backup of your photos. Granted, if you lost your camera you would lose both cards and potentially still be without a backup. But this option does provide insurance against a card failure.
However, as noted above, with most cameras you aren’t able to save video captures to two cards at a time. I assume this is purely a matter of bandwidth constraints, since video files tend to be rather large to begin with and thus require more time (and space) to save compared to still captures.
So, while I capture still photos to two cards at a time with my camera, video captures are only recorded to a single card. And even with this built-in backup, as noted above the backup is still located within your camera. Thus, if your camera were lost you would lose both copies of your photos. In other words, with photo or video captures that are of particular value to me, I am still eager to download the captures to a computer or other storage device as quickly as possible, in order to provide another backup on a separate physical device.