pentamirror means A system of three (not five) mirrors used as a cheaper substitute to a pentaprism in the viewfinders of some single-lens reflex cameras. Lexicurio rates it Sui generis — a strength score of 85 out of 100.
Etymology
From penta- + mirror.
noun
- A system of three (not five) mirrors used as a cheaper substitute to a pentaprism in the viewfinders of some single-lens reflex cameras