Help with the next focal length please? (1 Viewer)

I currently have a Canon 7d and a 300mm f4. Would I be better with adding the 1.4 teleconverter iii or a Sigma 50-500mm?

Or are there other recommendations?

The new Tamron 150-600 is getting a lot of praise for offering respectable 600mm at an affordable price (about the same at the Sigma you mention). It's main weakness seems to be the AF, so it's more useful for slower or static subjects than bird-in-flight.

There's always the tried and trusted 400mm f5.6 or 10-400.

They all have their stengths and weaknesses, so what are you looking for in the new gear?