The Sightron SIII 8x42 ED II Binoculars (MPN: SI-25180) are full-size roof-prism hunting binoculars engineered for steady handheld glassing across diverse terrain. Built around Japanese Extra-Low Dispersion (ED) glass elements and phase-corrected BAK-4 prisms, the optical system suppresses chromatic aberration while maximising light transmission. With an 8x magnification paired with 42 mm objective lenses, these binoculars produce a 5.25 mm exit pupil and an expansive 7.5° angular field of view (393 to 395 ft at 1,000 yards), allowing hunters and wildlife observers to track moving game quickly in timber or open country. The assembly is housed in a rubber-armoured magnesium chassis that is nitrogen-purged and O-ring sealed for complete waterproof and fogproof performance in adverse weather.

Key Features

• ED Optical System: Features Japanese Extra-Low Dispersion glass and fully multi-coated lenses to eliminate colour fringing and deliver sharp edge-to-edge contrast.
• Phase-Corrected Prisms: Roof prisms with phase coatings preserve resolution and light transmission when glassing in shadowed or overcast environments.
• Rugged Housing: Rubber-armoured magnesium chassis absorbs field impacts and provides a secure grip in wet conditions.
• All-Weather Reliability: Nitrogen-purged and O-ring sealed construction prevents internal fogging and ingress from rain or mud.
• Tripod Adaptable: Integrated standard 1/4"-20 threaded socket allows direct mounting to standard tripod adapters for stationary glassing sessions.

Specifications

• Magnification: 8x
• Objective Lens Diameter: 42 mm
• Exit Pupil: 5.25 mm
• Eye Relief: 18 mm (with multi-position twist-up eyecups)
• Field of View: 7.5° (393–395 ft at 1,000 yards / ~131–132 m at 1,000 m)
• Apparent Angle of View: ~52°
• Close Focus Distance: 6.6 ft (2.0 m)
• Prism Type: Phase-corrected BAK-4 roof prism
• Chassis Material: Rubber-armoured magnesium alloy
• Length: 5.27 inches (~134 mm)
• Weight: 26.1 oz (~740 g)
• Mount Interface: Standard 1/4"-20 threaded tripod socket

Who is the Sightron SIII 8x42 ED II Binoculars for?

• Spot-and-stalk big game hunters in dense bush or open country — The 8x magnification and 7.5° field of view (393–395 ft at 1,000 yards) on this roof-prism hunting binocular facilitate rapid target acquisition, while the 18 mm eye relief accommodates eyeglass wearers without field loss.
• Dawn and dusk wildlife observers requiring generous exit pupils — The 42 mm objective lenses deliver a 5.25 mm exit pupil that funnels maximum usable light to dilated eyes during low-light transitions, maintaining target clarity past 6.6 ft minimum focus.

Less suitable for: Identifying antler points or spotting game beyond 400 m, where higher-magnification optics (such as 10x42, 12x50, or dedicated spotting scopes) are required; macro entomology under 2 m, which requires specialised close-focus optics; or all-day mountain treks relying on a neck strap, where the 26.1 oz weight makes an 8x32 class binocular or an ergonomic chest harness a better fit to avoid fatigue.