Thanks everyone so far, I thought the 120-400 might be a bad choice which is why I walked away from it when I did. Until I did some more research. At this time I'm not interested in any Prime lenses due to the range of the different animals. As I was saying at the beginning those are the far extremes but there will be opportunities closer as well. This is leaning me toward looking for a Sigma 50-500mm. I missed one yesterday for $483 on
eBay. I stopped bidding until I had a chance to come here and learn more about the lenses and what all the other parts of the model numbers mean. I thought maybe there was something I was missing that caused the price to be what it was. Currently there is a *mint* one on
eBay for $620 +shipping. Sounds pretty interesting.
However, I'm still reading up on the Tamron 150-600 and the Sigma 150-600 before settling on that one.
Thanks everyone for your expertise on the lenses it's helping dramatically narrow the scope of the search.