One variant type was referred to as "trench binoculars", a mix of binoculars and periscope, often utilized for artillery recognizing functions. It projected only some inches previously mentioned the parapet, As a result retaining the viewer's head safely during the trench. Porro prism binoculars are named after Ignazio Porro, who https://canonmirrorless65318.blogcudinti.com/20058790/the-ultimate-guide-to-binoculars