Pentax UP WP U-Series BAK4 Porro Prism Waterproof Fogproof Binoculars

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Pentax's highly portable and functional U-Series UP WP Compact Binocular employs an innovative unibody design that locks the objective lenses into the body with the eyepieces set on a synchronised dual-axis mechanism that ensures they stay symmetrical in relation to the centre axis of the optic when adjusting the interpupillary distance. The 25mm objective lenses are fully multicoated to reduce reflection and maximise light transmission to produce the brightest images possible. Aspherical lens elements virtually eliminate distortion, especially around the edges, and corrects for lens astigmatism which can prevent sharp focusing.

Designed for easy carrying and stowing, the binocular features a lightweight fibreglass reinforced polycarbonate housing that is corrosion and impact resistant. The housing material is also temperature-resistant allowing for its use in extreme climates while reducing expansion and contraction wide temperature variations can cause, which can make the optical components move out of collimation over time. Its optical tubes are nitrogen-filled and O-ring sealed so they can are submersible to 3.3', as well as fogproof in all weather conditions.

Optical Performance

- 8x magnification

- 25mm objective lenses

- BAK4 porro-prism optical design

- Aspherical lens elements reduce distortion at the edges and corrects for lens astigmatism which can prevent sharp focusing

- Anti-reflection fully multi coated optics

- 5' field of view at 1000 yards

- 50° angle of view

Use and Handling

- Dual-axis synchronised eyepiece adjustment ensures symmetrical placement when changing interpupillary distances

- Knurled centre focus wheel

- Twist-up eyecups for use with or without eye wear

- 15mm eye relief, 3.1mm exit pupil

- Standard ¼ Inch -20 tripod mount

 Construction Details

Lightweight fibreglass reinforced polycarbonate housing

Housing is corrosion, temperature and impact-resistant

Nitrogen-filled for fogproof performance, submersible to 3.3' (1m)

Rubberized armoring protects against impacts and provides slip-resistant grip

Inner focusing mechanism provides smooth focus while preserving waterproof seals


- Prism Type: Porro

- Magnification: 8x

- Objective Lens Diameter: 25 mm

- Angle of View: 6.2° (actual)

- Field of View: 325.5' @ 1000 yd / 108.5 m @ 1000 m

- Minimum Focus Distance: 40.6' / 12.4 m

- Exit Pupil Diameter: 3.1 mm

- Eye Relief: 15 mm

- Interpupillary Adjustment: Not Specified by Manufacturer

 Dioptric Correction: Not Specified by Manufacturer

 Focus Type: Center

- Tripod Mount: Yes

- Weight: 12.3 oz / 348.7 g

In the Box:

- Pentax U-Series UP WP Compact Binocular

- Neck Strap

- Carrying Case

- 2 x Eyepiece Caps