The Sigma 100-400mm F5-6.3 DG DN OS is an excellent telephoto lens for wildlife! It’s smaller, lighter and less expensive than the Sony 100-400GM. That’s an exceptional lens but I needed something smaller and lighter for wildlife photos and videos while backpacking. I hike with the Sony 24-70GM attached to my Sony a7Riv. When I want to photograph/video bears etc. this Sigma lens has more than ample reach. I’ve found the Sigma 100-400mm’s build quality to be excellent! The lens can be locked during transport. The lens hood is designed to provide push/pull zoom functionality and that’s a great feature! Stabilization can be toggled on and off my using the button on the side of the lens. There is also a focus hold button and an AF to MF toggle switch. I also like the black color of the lens. It doesn’t scream, “look at my expensive wildlife lens,” like most of the white-colored lenses do! #Sigma #Lens