National Geographic 10x42mm Open Bridge Binocular, Black
An open bridge binocular replaces the solid centre section with two short hinges and a gap between them, and the reason is entirely about how it sits in the hand. Your fingers wrap through the opening rather than around a solid block, which gives a more secure one handed hold, removes weight from the middle of the instrument and makes it easier to raise quickly with one hand while the other is occupied.
The 10x42mm open bridge specification
The optical layout is a roof design using BaK-4 prisms with fully multi coated lenses, which together produce the sharpness and colour depth that separate a good pair from a cheap one. Ten times magnification with 42 millimetre objectives gives the reach for mid to long range observation and enough aperture to keep the image bright in early morning and late afternoon light.
Field of view, near focus and mounting
Across 1000 metres the view spans 114 metres, which is wide for a 10x pair and makes finding a moving subject considerably easier. Near focus is 4 metres. A diopter setting corrects each eye independently, the eyepieces suit eyeglass wearers, and a tripod adapter thread is fitted for extended observation.
Sealing
The body is waterproof and purged with inert gas, which keeps water out and stops the internal condensation that forms when a cold instrument is carried into warm air.
Full features and the complete specification table appear below.
Features
- BAK-4 roof prisms
- Multi-coated lenses for sharpness and vivid colours
- Waterproof
- Fogproof
- Open bridge design makes the binoculars easy to hold, lightweight and aesthetically pleasing
Specifications
| Optical Design |
Roof |
| Magnification |
10x |
| Mirror/Lens Diameter |
42 mm |
| Material Prism |
BaK-4 |
| Type Of Coating |
Fully multi-coated |
| Eyepieces For Eyeglass Wearers |
Yes |
| Diopter Setting |
Yes |
| Field Of View At 1000m7 |
114m |
| Near Focus From7 |
4m |
| Waterproof |
Yes |
| Inert Gas Purged |
Yes |
| Tripod Adapter Thread |
Yes |
| Colour |
Black |