Structure and Optical Technologies
Focus adjustment
Focusing of CF binoculars


Rotating the central focusing ring engages the internal shafts. Then, the tubes that fix internal lenses (concave lens) move so that the binoculars focus. Because objective lens and eyepiece lens are fixed, binoculars can have a highly airtight structure. This is recommended for CF (Central Focusing) waterproof binoculars.
Focusing of IF binoculars


Rotating diopter adjustment rings that are located on both left and right eyepieces, moves the entire eyepiece lens unit in order to focus.
Sport Optics Guide -Binoculars-
Basic Information about Binoculars
How to Choose Binoculars
How to Use Binoculars
Structure and Optical Technologies
- Internal structure
- Focus adjustment
- Magnification principle
- Lenses of binoculars
- Lens coatings
- Prisms of binoculars
- Coating on roof (Dach) prism
- Aberrations
- Resolution