Pentaprism Viewfinder : Components and Operation

Pentaprism Viewfinder is special type of prism viewfinder, which is usually used on DSLR and old SLR cameras. Pentaprism Viewfinder allows the view through the lens without inverting it. This intuitive picture framing is easier than the viewfinder. In Pentaprism Viewfinder, the design is done so that the incident rays falls at an angle less than the critical angle nullifying total internal reflection.

Components of Pentaprism Viewfinder

In most DSLR cameras viewfinder is an integral part of the camera. When the camera viewfinder is equipped with interchangeable focusing screen is the camera, either a part of the prism viewfinder / Pentaprism Viewfinder be removed or changed. Following are the components of Pentaprism Viewfinder :

• Focusing screen
• Roof-prism (pentaprism)
• Finderscope
• Housing

Operation of Pentaprism Viewfinder

In a DSLR camera, Pentaprism Viewfinder generates the image by the light passes through the lens into the camera. There is a 45-degree angled mirror that projects onto a screen positioned horizontally above the mirror, which reflects the viewfinder the image along the vertical axis (left-right is reversed) and tilts from horizontal to vertical. At the back of the camera, ie behind the prism, sits the viewfinder, a lens system, which ensures that the viewer can clearly see the viewfinder image. Pentaprism Viewfinder again makes the proper adjustment so that the final image becomes without changing the image’s handedness.

Pentaprism Viewfinder versus Pentamirror Viewfinder

Although Pentamirror Viewfinder technically produces the exact result that of a Pentaprism Viewfinder, Pentaprisms are generally brighter and seen in the better cameras.  Pentamirror Viewfinder replacements are generally less bight and yield a smaller image when looking through the viewfinder.