I have recently posted a similar post.... still needing advice before I make the investment.

Right now I am deciding between the Sigma 300mm f/2.8 and the Sigma 50-500mm. The 300mm is the most I want to spend on a lens. The low f stop still gives me the room to add a teleconvertor to get that extra reach. The 50-500 is considerably cheaper. You give up several f stops for the cheaper price though.

Do I spend the extra money for the f-stop? Or save the money and get the other (nicely reviewed) 50-500mm?

Lens will be for bird/wildlife pics...

Or is there another lens out there that I may be missing out on?

Thanks-