Nikon D300 User Manual page 107

Last year I shot around 100 GB of image files. With the
newest memory cards now hitting 64 GB, I can foresee a time
when the card(s) in my camera will become a yearlong
backup source.
At the present time, I do not use the Active folder
functionality all that much, but I guarantee you I will in the
near future. This is a good function to learn how to use!
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