Why does my D300s use up my memory cards quicker than my D80?
Paul Moss, Wateringbury, UK
Chris says… It sounds like this conundrum has been causing you sleepless nights. You tell me that you set up both your Nikons for a shoot with newly-formatted 8GB cards, but while the D80 offered you a capacity of 620 NEF files, the D300s indicated space for 320.
The D80 has a 10.2-megapixel sensor, whereas the D300s has a 12.3-megapixel chip, so we would assume that the D80 will be able to fit more shots onto a card. But that does not explain why the difference in capacity is so great. However, not all RAW files are the same. The D80 offers only one type: 12-bit compressed NEFs. This is the most memory-efficient setting. The more pro-level D300s gives you a choice between 12-bit and 14-bit and between Uncompressed, Lossless Compressed, and Compressed options.
My guess is that you have your D300s set to the 14-bit Uncompressed option, which gives the best quality but the fewest shots per card. Switch to 12-bit Compressed in the Shooting menu (look for Type, within the NEF (RAW) Recording option), and you should get 540 shots on your 8MB card.
Nikon SLR instruction manuals have a table at the back telling you the rough capacity for every Image Quality setting your camera offers.