viewfinder

As a noun viewfinder is

a device on a camera that shows what will appear in the field of view of the lens; it helps the user target a subject, zoom and focus the image.

As nouns the difference between taxonomy and viewfinder

is that taxonomy is the science or the technique used to make a classification while viewfinder is a device on a camera that shows what will appear in the field of view of the lens; it helps the user target a subject, zoom and focus the image.

As nouns the difference between viewfinder and pentaprism

is that viewfinder is a device on a camera that shows what will appear in the field of view of the lens; it helps the user target a subject, zoom and focus the while pentaprism is a five-sided prism used in the viewfinder of some single-lens reflex cameras.

As nouns the difference between viewfinder and pentamirror

is that viewfinder is a device on a camera that shows what will appear in the field of view of the lens; it helps the user target a subject, zoom and focus the while pentamirror is a system of three (not five) mirrors used as a cheaper substitute to a pentaprism in the viewfinders of some single-lens reflex cameras.

As nouns the difference between viewfinder and mirrorless

is that viewfinder is a device on a camera that shows what will appear in the field of view of the lens; it helps the user target a subject, zoom and focus the while mirrorless is a mirrorless interchangeable-lens camera, similar to a digital SLR, but usually made smaller by incorporating an electronic viewfinder instead of a mirror and prism.

As an adjective mirrorless is

without a mirror.