amehta wrote:
The OP wants to also use a teleconverter, which the Tamron will not do.
I do wonder who has compared the Tamron 150-600mm with either Canon lens? The DxOMark ratings show a pretty significant difference (24 vs 17), which may only noticed with a big print. But if Willy has the means, and he has obviously kept his financial house in order, and wants to get the best lens, I think the Canon wins.
The Tamron 150-600mm does a great job of what I seen are mostly stationary objects and it is a zoom. There's a gentleman from England that has done some BIF with that lens on the forum and they look good. I'm not sure of how well the AF works as it's been reported that people were experiencing problems with the AF and also focus out past 300mm. If you were Tamron and everyone with a Nikon wanted one and we are talking about making money now tell me why they're not selling it with a Nikon mount. I don't buy the story that Canon has a lock on it either. When Tamron can mass produce that lens in mounts other than Canon we'll have more input from all makes to evaluate it . Back to the main point, is it a Canon 200-400mm f/4 with a built in 1.4 TC or a Canon 500 or 600mmf/4.0, we got off track somewhere.