Roof Prism Binoculars

More Information  · Recommended Accessories Price $249.95 List Price $389.95 Optical Type Roof Prism Field of view 6° Field of view 1000 yards 315' Exit Pupil 4.2mm Relative Brightness 17.64 Twilight Factor 20.49 Eye Relief 13mm Interpupillary Distance 58-74mm Close Focus 6' Weight 27.5 oz Height 5.6" Armored Yes Waterproof Yes Warranty Limited Lifetime

The phase-coated BaK-4 optics are fully multicoated for high light transmission and contrast. Usable eye relief is a reasonable 13mm. While this is fine for unaided observing, it will vignette the field somewhat for those who must wear eyeglasses while observing. Twist-up eyecups convert quickly from unaided viewing to eyeglass or sunglass use. One and a quarter turns of the focus knob moves the focus from 6’ (very good for a 10x binocular) out to the horizon. The depth of field is more than acceptable for close-in birding (we’d guesstimate a usable depth of field of about 10"-11" for us at a distance of 7’, although your tolerance for a wee bit of unsharpness at the near and far sides of that distance may be less than ours). Curvature of field is minimal, as are astigmatism and barrel distortion. The result is images that stay usably sharp across most of the field for a view that is easy on the eyes for extended observing sessions.

Overall, this is optically and mechanically a quite good high power phase-coated binocular at a surprisingly reasonable price.

Features of this binocular . . .

Roof prism design. H-body roof prism design with internal center focus puts large aperture optics in a compact package.

Fully multicoated optics. Multilayer antireflection coatings on all air to glass surfaces for maximum light transmission.

Phase-coated. PC-3 phase-correcting optical coatings on the BaK-4 prisms (the same as on the top-of-the-line Bausch & Lomb Elite binoculars) provide high contrast and resolution. This is particularly visible in the shadowed areas of a backlit or silhouetted bird when observing into the rising or setting sun or when observing in shadowed woodlands.

Waterproof and fogproof. Dry nitrogen-filled and O-ring sealed to be waterproof and fogproof in all temperature and climate extremes. Designed to operate reliably in rainforests and deserts alike.

Rainguard lens coatings. Special hydrophobic (water-repelling) coatings applied to the external optics cause the condensation from rain, fog, or snow to form in much smaller droplets than on standard optical coatings. Smaller droplets scatter less light, resulting in higher light transmission and a clearer image.

Armor. Ribbed and textured black rubber armor absorbs noise and shock. Molded-in thumb grooves and a contoured body shape keep the hands positioned perfectly for proper balance.

Twist-up eyecups. A quarter turn of the rubber-rimmed eyecups retracts them into the binocular body for eyeglass or sunglass use, rather than rolling down. This eliminates the possibility of the eyecups drying out and cracking with age and use, as with conventional rolldown eyecups. A quarter turn in the opposite direction extends the eyecups for non-eyeglass use.

Excellent close focusing. Only one and a quarter turns of the comfortably-large ribbed focus knob moves from an exceptionally good 6’ near focus to the horizon.

Rotary diopter correction. A continuously variable diopter ring on the right eyepiece allows you to match the binocular optics precisely to your individual eyesight for a sharp image. The ring is stiff in its operation. In addition, the contoured body shape keeps the ribbed adjustment ring out of the way of your hands when the binocular is in use. These features make it unlikely that the diopter control will accidentally be moved out of adjustment when you least expect it, as is often the case with lesser binoculars.

Wide neck strap. The comfortable wide woven neck strap makes the binocular easy to carry during all-day birding sessions.

Tripod adaptable. A standard 1/4"-20 thread socket for attaching an optional tripod adapter is located at the front end of the binocular’s center hinge. A thread-in plastic logo plate covers the tripod socket when not in use.

Soft case. A soft leather-like vinyl case (similar to the one that comes with the high end Bausch & Lomb Elite binoculars) is standard equipment.