Hi, I'm looking to upgrade my 100-400mm lens to a longer and faster option. I've been looking at the 500mm f4 which seem the most popular choice but to be honest, I'd struggle to justify the expense. The new sigma 120-300 f2.8 with OS is supposed to be a nice lens, but does anyone have any experience with this lens. Do you see this as a good upgrade from my current 100-400mm. I could really do with the help and advice.
Thanks
Simon


