Hi everyone, I have been shooting sports with my 70-200mm f/2.8 (non-IS) for about 2 years and I'm very happy with the result I get. I shoot mostly triathlon, running, swimming and cycling. I usually have access to most part of the course so my 70-200 is perfect.
However, I sometime wish I have more reach when it comes down to open water swimming. I started looking at used 400mm f/2.8 but I found that there is 4 or 5 version of this lens. Can someone recommend me a good one to get, and what to look at when buying used lens like that. I have a budget around 3000$ and I want image quality to be at least as good as my 70-200mm at 2.8.