This Could Be The Only Lens You NeedIf Manufacturers Werent Fooling Around

The other day, I was thinking about having just a single zoom lens. APS-C cameras and Micro Four Thirds cameras have that with one of the best being the Tamron 18-300mm that we reviewed a while back. And the closest and best I've seen for full-frame is the Nikon 28-400mm and the Tamron 28-300mm. But why can't they go even wider? Manufacturers say that an 18-300mm lens for full-frame would be so big. However, I don't really think that it would be.