Penta Prisms

CPG provide high accuracy Pentaprisms for over 10 years. For both traditional application and filter like prism, CPG should be your first choice. 

  • 90° beam deviation
  • Up to 10 arc sec accuracy
  • Image neither inverted nor reversed
  • Insensitive to alignment
  • Customized dimensions and coating
  • Various variant choices

In traditional application, a pentaprism is a five-sided reflecting prism, aim to deviate a beam by a constant 90°, even if the entry beam is not at 90° AOI to the prism.


For traditional application, the Pentapirsm will neither invert nor reverse the image. These prisms control the beam through the same angle and handedness as an ordinary right-angle prism or mirror would. The monolithic design also makes the prism inherently more stable than a system consisting of two or more mirrors.
Roof pentaprism is another variant of this kind of prism, it used widely in photographic application; it has two sloping sides on one of the reflecting surfaces.

Roof Pentaprism.SvgLight Path 21

The standard Penta Prism reflecting surfaces are coated with aluminum or enhanced aluminum(see Coating chapter). Sometimes, the coated surfaces are with black painting.

Another variant of the pentaprism is to add a wedge prism on one of its surfaces, then pentaprism will be used as a beamsplitter, CPG also provide this kind of part to a lot of customers or end users. With our experiences of design different coating and angle, customized application is still available.

Pentaprism 3

Typical Specification

Material BK7/Fused Slica etc
Dimension Tolerance +/-0.1mm
90° Deviation Tolerance

Standard series: < 30 arc seconds

Precision series: up to 10 arc seconds


Standard series: 1/4 at 632.8 nm

Precision series: up to 1/4 @ 632.8 nm

Reflectivity R > 95% per face from 630 to 680 nm
Surface Quality 40-20 scratch and dig