Roof Prism, Amici Roof Prism, Schmidt Prism, Roof Pentaprism Overview: A roof prism, also called a Dachkanten prism or Dach prism is a reflective prism containing a section where two faces meet at
a 90° angle, resembling the roof of a building and thus the name.
Reflection from the two 90° faces returns an image that is flipped
laterally across the axis where the faces meet. Characteristic for a roof prism is that the beam is split in half,
with one half of the beam hitting first one face then the other
face, while it is invert for the other half of the beam. Therefore,
a roof prism can be used only with some distance to focal planes,
or the "edge" of the roof would introduce slight distortions.
Furthermore, the angle between the two faces has to be very close
to 90°, or image quality would be degraded. The simplest roof prism is the Amici roof prism(Roof Right Angle Prism), with other common roof prism designs being the Schmidt prism and probably the best known being the roof pentaprism. Manufacturing Capacity of Roof Prism: | Material | BK7, Fused Silica, other optical glass | | Dimension Tolerance | +0.0/-0.2mm | | Clear Aperture | >90% | | Angle Tolerance | Up to 10 arc seconds | | Roof Angle Tolerance | Up to 3 arc seconds | | Flatness | Up to λ/10@632.8nm | | Surface Quality | Up to 20/10 scratch and dig |
An Amici roof prism, sometimes called an Amici prism or right angle roof prism, is a type of reflecting prism used to deviate a beam of light by
90° while simultaneously inverting the image. It is commonly used
in the eyepieces of telescopes as an image erecting system and any
optical instrument where it is desirable to take an inverted image
from an objective, turn it right side up, and bend it through a 90°
angle in order to maintain the correct visual orientation.
The Schmidt prism, is a prism that reverts an image while deviating the line of
sight by 45° makes Schmidt prisms especially useful in eyepiece assemblies and
imaging systems requiring a path bend.
Roof pentaprism is a variant of Penta Prism which is commonly used in the
viewfinder of single-lens reflex cameras. | 
