For $600 USD, this is an absolute STEAL of a lens. It is also very light, and has sufficient sharpness and focusing speed. The biggest negative is it is f/5.6-8, which means it is mostly an outdoor lens, and you wont be using it in low light without your ISO cranked through the roof. Even though I own the 100-500 RF, Im still hanging on to this guy as I travel extensively, and therefore has a specific use in my tool kit. Highly recommended if you are a budget and looking for a tele RF zoom.