Want to get a lens (hopefully soon) to take some pictures of birds from my front porch. With the crop factor, the 50 end of my 12-50 is almost but not quite ok to get to the two large trees in my front yard. I was thinking about the Oly 75-300. Then there’s the Panasonic 100-300 and 45-200 (?). Reading about the Oly 75/1.8 and maybe it would be an option. Then I could get a Nikon adapter and have a 180/2.8 ED that I love on my F2 and see a lot of 300 f/4 Nikkors pretty cheap. So what is the best available bird tele right now? similarly related question, best bang for the buck?