I Have been looking for a nice birding lens for some time now in the 400mm to 500mm range , I would like to stay in the 500 dollar range. So that means i will have to buy used if i want a good lens. I have been burned with buying a older sigma 400mm prime lens with the AF gear stripping out .But that does not mean i won't buy sigma i just will be doing more research and asking others what they think. I was looking at a Sigma 135-400mm f/4.5-5.6 AF Mt APO Lens has anyone used one of these or could anyone send me in the right direction.
Thank you