Full size binoculars refer to glass with an objective lens diameter of at least 40mm. These binoculars are great for general-purpose uses, but they are particularly useful for hunting. The larger objective lens lets in more light, making these binoculars better suited for dawn and dusk than smaller models. They can also be used for bird watching, nature observation, and longer viewing sessions. Full-sized binoculars can also be used for astronomical purposes thanks to their low-light capability.