Gadget Bag: Compact Binoculars

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There are a large number of choices when it comes to binoculars. Companies are continually increasing the quality of their optics, glass coatings, weatherproofing and focus range while also expanding their model sizing. While this proliferation keeps competing manufacturers producing the most up-to-date tools, it can make purchasing decisions overwhelming.

To slim down the field, let’s look specifically at 10×25 compact binoculars. Advanced birders may be particular about the size and magnification they use to match their preferences, but for multipurpose photographers interested in travel-friendly binoculars, 10×25 compacts are a go-to for several reasons.

The 10x magnification strength is great enough to provide visibility for distinguishing animal markings, but not such a high strength that a tripod becomes necessary for steady viewing. Handheld use (and general portability) is a strong suit of the 10x25s, as these compacts tend to be lighter than larger- and smaller-magnification binoculars because of their specific optics.

When looking at different brands of binoculars, there are several factors to note to find your best match. The first factor is the prism. Prisms act like mirrors to shorten the optical path, allowing binoculars to become smaller, as well as flip the image right-side-up after it has been inverted by the optics. Two types of prisms are used.

Porro prisms have a Z-shaped optical path, as the objective lens is slightly askew from the eyepiece, giving a greater depth perception and wide field of view. All the surfaces are reflective, providing no light loss. But porro prisms take up more space than roof prisms. For this reason, the majority of 10×25 compacts utilize a roof-prism design. In roof prisms, the objective lens and eyepiece are in alignment and the optical path is a bit longer. Some roof prisms employ BaK-7 glass, but BaK-4 is considered premier quality. There’s some light loss with roof prisms, so various coatings are used to minimize this loss.

Roof prisms split light into two paths, then reconnect the image. This split has the potential to cause polarization. To negate this effect, many manufacturers add a phase-correction coating. Anti-reflective coatings are also used to reduce light loss and increase contrast. Adding this can make a huge difference, upgrading smaller-objective lenses with the coating to have a noticeable advantage over large-objective lenses without it. Multicoated binoculars have antireflective coatings on one or more surfaces. Fully coated models have a single antireflective coating on air-to-glass surfaces.

Within the group of 10×25 compact binoculars, each pair will have a varying field of view, close-focus distance, level of weatherproofing, and be within a different budget bracket. Here are several options to explore for meeting your binocular needs.

The Brunton Echo Compact Dual Hinge binoculars use a polymer frame with an ergonomic body armor to house a BaK-4 roof prism with full multicoating. The 7.8-ounce optics use a fold-down eyecup and provide a field of view of 424 feet at 1,000 yards, with a 12-foot close focus. www.brunton.com

Bushnell H2O

Bushnell‘s Legend Ultra HDs utilize ED prime glass and a BaK-4 roof prism with PC-3 phase coating, Ultra Wide Band Coating and fully multicoated optics. In addition to being waterproof and fogproof, the binoculars also have a Rain Guard HD permanent water-repellent lens coating. At 8.1 ounces, they have a field of view of 285 feet at 1,000 yards and a 6-foot close focus. The Bushnell H2Os are ready for wet weather, as they’re 100% waterproof with an O-ring seal and nitrogen-purged to negate fog. The rubber armor secures grip and increases shock absorption. Featuring BaK-4 roof prisms and multicoated optics, the 10.23-ounce optics have a field of view of 342 feet at 1,000 yards and a 15-foot close focus. www.bushnell.com

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Celestron Nature DX 10×25

The Celestron Nature DX 10×25s weigh 12.1 ounces, with a polycarbonate frame and multistep twist-up eyecups. The binoculars use a BaK-4 prism with phase coating and multicoated optics. The Nature DX are waterproof, providing a field of view of 315 feet at 1,000 yards, with a 6.5-foot close focus. Celestron’s Cypress 10×25s weigh 11.9 ounces, with a polycarbonate frame and twist-up eyecups. With a BaK-4 reverse porro prism and multicoated optics, the binoculars are waterproof and fogproof, with a field of view of 283 feet at 1,000 yards and a 9.8-foot close focus. www.celestron.com

Humvee HMV-B-10x25B

The 5.6-ounce Humvee HMV-B-10x25B sport optics have a roof prism with antireflective red glass lenses. A black rubber coating ensures a firm grip. They provide a field of view of 304 feet at 1,000 yards, with a 13-foot close focus. www.humvee.com

The Leica Trinovid BCAs feature a water-resistant aluminum body with nonslip rubber armor that houses a phase-coated roof prism with HDC-coated optics for color fidelity and contrast. A folding mechanism makes the binoculars particularly compact. At 9 ounces, the BCAs provide a field of view of 273 feet at 1,000 yards, with a 16.4-foot close focus. us.leica-camera.com

The 12.7-ounce Leupold BX-1 Rogue binoculars use an ergonomic armor-coated, waterproof body to protect the BaK-4 porro-prism design. The lens system is fully multicoated and provides a 14.10-foot close focus with twist-up eyecups. www.leupold.com

Minox‘s BV binoculars weigh 9.14 ounces, with an aluminum body and rubber armor. With a roof prism and multicoated optics, they’re fully sealed against dirt, waterproof down to 9.8 feet, and nitrogen-filled for fogproofing and corrosion-resistance. The BVs have a field of view of 290 feet at 1,000 yards, with a 4.9-foot close focus. www.minox.com

Nikon Aculon A30;

The Nikon ACULON A30 sport optics weigh 9.7 ounces, with a dual-hinge fold-up design, rubber-coated grip and rubber eyecups. The roof-prism model features multicoated Eco-Glass lenses and provides a field of view of 262 feet at 1,000 yards and 9.8-foot close focus. nikonsportoptics.com

Pentax DCF SW

The 10.6-ounce Pentax DCF SWs use a roof prism with phase and super-reflective coatings, and multicoated optics. The dual-hinge, rubber-covered body has a helicoid eyepiece ring with four click stops and is both fogproof and waterproof down to 3 feet, with a field of view of 261 feet at 1,000 yards. www.us.ricoh-imaging.com

Weighing 9.87 ounces, the Orros 1025 binoculars by Vanguard use a BaK-4 prism and multicoated lenses for sharp detailed viewing. The nonslip rugged body with an offset focus wheel is O-ring-sealed and nitrogen-charged to be waterproof and fogproof, providing an 8.2-foot close focus. www.vanguardworld.com

Zeiss Victory Compact 10×25 T*

The 8.8-ounce Zeiss Victory Compact 10×25 T* sport optics use a dielectrically coated Schmidt-Pechan roof prism and T* multilayer lens coatings. The shockproof rubber armor protects the nitrogen-filled 100% waterproof body. A LotuTec coating covers the lens and eyepiece for water- and dust-resistance. The optics provide a field of view of 285 feet at 1,000 yards, with a 13.12-foot close focus. www.zeiss.com/sports-optics