A prism having a five-sided cross section with two silvered surfaces, giving a constant deviation of all rays of light through 90°, used chiefly in the viewfinders of single-lens reflex cameras.
（主要用作单反照相机取景器的）五棱镜
Example sentencesExamples
I was just looking through my junk bin over the weekend and I found that I have a number of pentaprisms taken out of 35mm SLR cameras.
Pros, from what I've read, is that mirror pentaprisms are lighter, can be made smaller to save space, and are cheaper to manufacture than glass pentaprisms.
DSLR (Digital Single Lens Reflex) by definition have optical viewfinders, usually consisting of a instant-return mirror and a pentaprism.
Definition of pentaprism in US English:
pentaprism
nounˈpen(t)əˌprizəmˈpɛn(t)əˌprɪzəm
A five-sided prism with two silvered surfaces giving a constant deviation of all rays of light through 90°, used chiefly in the viewfinders of single-lens reflex cameras.
（主要用作单反照相机取景器的）五棱镜
Example sentencesExamples
Pros, from what I've read, is that mirror pentaprisms are lighter, can be made smaller to save space, and are cheaper to manufacture than glass pentaprisms.
I was just looking through my junk bin over the weekend and I found that I have a number of pentaprisms taken out of 35mm SLR cameras.
DSLR (Digital Single Lens Reflex) by definition have optical viewfinders, usually consisting of a instant-return mirror and a pentaprism.