Hello all, I was wondering what size pelican I should buy? Im looking for a case that will hold a 40D, 18-55, 50, and maybe a 50-250 along with batteries. I need it to be waterproof because I want it to be able to fit in my backpack while I go fishing. What is the smallest pelican I can get away with? I was thinking the 1300 if I could squeeze it. Let me know what you think.