Sightron SI 825TAC 8x25 binocular

Compact 8×25 roof-prism binocular

The Sightron SI 825TAC is an 8×25 roof-prism binocular built for daytime outdoor use. Multi-coated lenses improve light transmission and reduce glare. A waterproof body protects the optics in rain or wet conditions. The ranging reticle lets users estimate distance or object size in the field.

For hikers and birdwatchers who want a light.

The 25 mm objectives keep weight and bulk low for all-day carry. The 7.9° angle of view gives a wide picture for tracking moving subjects. Buyers who need brighter images in deep shade or at dusk should consider models with larger objective lenses. The fixed 8× magnification also means the view cannot be zoomed for distant detail.

8× magnification with 25 mm objectives

This combination sets the exit pupil at roughly 3 mm, which is adequate in good light but smaller than the eye's dark-adapted pupil. The 7.9° angular field of view translates to a generous linear width at 1 000 m. The ranging reticle is etched on the prism assembly and calibrated for the 8× power.