I need more reach with my 70-200 2.8II, but have no knowledge of converters because I had a 300mm for the reach. I just wanted to ask which converter, from any brand, is the best "bang for your buck", and which one produces the best results. Hopefully it can be both, but I will settle for results over price. It could be 1.4 or 2x, but I just need something with more reach. Thanks!