Carson Optical Binoculars - Manual (Page 4)

Zoom binoculars offer the user a range of magnifications. The zoom function can be operated by
hand using a lever, or by switch when driven by a motor. Zoom systems vary by model.
Waterproof binoculars and fog-proof binoculars should be nitrogen purged and O-ring sealed in order
for their internal lenses to be truly resistant to fogging and/or water damage.
Style of Binoculars – Porro or Roof Prism Design
Binoculars come in two distinct styles in which design is dependent upon the type of prism system
used. The image that passes through a binocular is upside down (a function of the lens) and needs to be
corrected. This prism is the optical glass inside a binocular whose purpose is to “invert” the image.
Roof Prism System: the prisms overlap closely allowing the
objective (front) lens to line up directly with the eyepieces.
The result is a slim, streamlined shape in which the lenses and
prisms that magnify and correct the image are in a straight line.
eyepiece
objective lens