I recently upgraded to a Canon 5d (my previous camera was a 30d which I kept as backup). Prior to purchasing the 5d I rented one to see if I would like it. I liked it. One thing I don’t like about the 5d however (and I noticed this about the camera when I rented it) was the amount of time it took to upload images from my compact flash memory card onto the computer compared to the 30d (I don’t use a card reader yet). What usually takes five minutes to upload 20 images with the 30d took over an hour with the 5d. Obviously the RAW files in the largest format on a 5d takes a lot of memory compared to the 30d but when you’re pressed for time all that waiting can be irksome. Then I had an idea. I wondered what would happen if I took the card out of the 5d and put it in the 30d THEN uploaded the images onto the computer. In other words would the images upload onto the computer faster. And sure enough they did. One good reason to keep your old camera.