I've own a 1D MKII for a few years now, it's never missed a beat, has been a great camera and servant, but it's showing its age, batteries aren't giving me a full days use anymore and the ISO capabilities are causing me the most problems even with my prime lenses, so it's time to upgrade. I photograph Motorsport and Wildlife, so the autofocus and ISO capabilities are important to me. I have a second body which is the 70D, it's a good second, but it's autofocus system doesn't come close to the 1D MKII. My question is, a used 1D MKIV or new/used 7D MKII as a replacement. I've heard that the 7D battery hungry, hence I would probably need a battery grip and battery, I know that the 7D has 4 or 8 point autofocus expansion, but having never really been impressed with the original 7D and I'm not convinced the MKII the way to go, plus it's another 1.6 crop camera, I've liked the 1.3 crop on the 1D, convince me that the 7D MKII the better choice.