Hello all! So I've been using my EF-S 55-250mm IS but I'm starting to desire a liiiiiiiiittle bit more reach and maybe a little bit better quality. So far I've seen: 1. Canon 100-400mm IS L 2. Sigma 50-500mm f/4-6.3 EX DG HSM 3. Canon 75-300mm f/4-5.6 USM IS 4. Canon 70-200mm f/4 L I'd probably get a 1.4X teleconverter for option 3 or 4. Thoughts? Opinions? Other options?