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.
- ‘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.’
- ‘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.’
We take a look at several popular, though confusing, punctuation marks.