What is the difference between a porro prism and a roof prism?
To display images in their correct orientation, binoculars either feature a porro prism or a roof prism. Porro prisms provide users with the best optics, and they are much more affordable overall than binoculars with roof prisms. Roof prisms can match (but not exceed) the optic performance of porro prisms, but they will always be more expensive than porro prisms with similar optical quality. That said, binoculars with porro prisms have recently been declining in popularity for a few reasons. Porro prisms can break easily if knocked around or dropped, and they also tend to be bulkier than binoculars with roof prisms. Roof prisms are not only much more durable but they are also more compact and lightweight. If you are on a budget and only plan on using your binoculars occasionally, porro prisms offer the best bang for the buck. However, if you will be using your binoculars very often for rugged activities, you are better off investing in binoculars with a roof prism.