Thank you for the spread sheet. I put it to good use on my latest trip to Orlando. I went from Nikon film cameras to the Nikon d100 and last month purchased a d300. It takes fome learning but you spread sheet made my photo shoot of Sea World and Gator land a pleasure. Very happy with the pictures from both cameras. I carried both cameras plus a phot vest for compact cards and extra lens, worked better then lugging a camera bag. I am presently using a NIkon 70-300, Sigma 12-24, Nikon 24-85. This gives me pleanty of breathing room. I am looking to roiund this off with a 200 -500 for sports and amimal photography,also photo journalism. I have looked at the Sigma and the Nikon, very pricey. I did some reading on the Tmaarom SO AF 200-500. I understand it works well with the d300. Can you or anyone in the group tell me anything about this lens.