I used the 16l backpack for my PEN and am very happy with it. The camera plus 3 lenses, cables, Gorillapod and Tablet fit into it perfectly and it stays up space for small items. The E-P3 fits well with the 40-150 in all positions well inside. With a little practice can also open the backpack without removing it. A rain cover protects against bad weather. Additionally, the backpack looks great and is very comfortable to wear and does not wobble on the back. For me also the removable photo compartment was important as I can so stow the backpack when traveling well in the trunk. For a DSLR backpack is rather small. A D5000 with 18-105mm lens and the SB-400 just fit into it.
