Kowa BD II XD 10x42 vs Kowa BD III XD 10x42
Field of view, to scale
Top-down view · drawn to true scale — no exaggeration
Which one to buy
Same $499 price, same 378 ft field, same 5.9 ft close focus, same 16.5mm eye relief: on paper the Kowa BD III XD 10x42 is the BD II in a smaller, lighter body. It weighs 21.5 oz against 22.8, and is 5.3 inches long against 5.6. Kowa presents it as the successor, keeping the same fluorite-rich XD glass.
The Kowa BD II XD 10x42 is the one with an owner record. Birders praise its wide field for following small, fast birds, its close focus for butterflies, and a bright, sharp center. The known compromises are softness and distortion in the outer field, some leftover color fringing off-center, and uneven quality control, with some owners sending units back for focus slop. Kowa's repair service gets good marks when that happens.
At the same price, the BD III is the one to buy unless you specifically want the BD II's locking diopter and tripod adaptability. It shares the glass and the field, so the view should be close to the BD II's. Either way, buy from a dealer with easy returns, as BD II owners advise.
Kowa BD II XD 10x42
Only worth choosing for its locking diopter and tripod adaptability, or if you find it discounted as the BD III takes over.
Kowa BD III XD 10x42
At the same $499, the lighter and more compact successor with the same glass and field is the default choice.
| Spec | Kowa BD II XD 10x42 | Kowa BD III XD 10x42 |
|---|---|---|
| Approx. price | ~$499 | ~$499 |
| Use case | Birding | Birding |
| Magnification | 10x | 10x |
| Objective | 42mm | 42mm |
| Exit pupil | 4.2mm | 4.2mm |
| Field of view | 378 ft @ 1000 yds | 378 ft @ 1000 yds |
| Eye relief | 16.5mm | 16.5mm |
| Close focus | 5.9 ft | 5.9 ft |
| Prism | Roof | Roof |
| Glass | ED | ED |
| Coating | Fully Multi-Coated | Fully Multi-Coated |
| Weight | 22.8 oz | 21.5 oz |
| Dimensions | 5.6 x 5.0 in | 5.3 x 5.0 in |
| Warranty | Limited Lifetime | Limited Lifetime |
Feature comparison
Kowa BD II XD 10x42
- ✓ED Glass
- ✓Phase-Corrected
- ✓Dielectric Coating
- ✓Waterproof
- ✓Fogproof
- ✗Image Stabilized
- ✓Tripod Adaptable
- ✗Magnesium Body
- ✓Locking Diopter
Kowa BD III XD 10x42
- ✓ED Glass
- ✗Phase-Corrected
- ✗Dielectric Coating
- ✓Waterproof
- ✓Fogproof
- ✗Image Stabilized
- ✗Tripod Adaptable
- ✓Magnesium Body
- ✗Locking Diopter
What birders say
Kowa BD II XD 10x42
- ✓Class-leading field of view for a 10x42 roof prism - the wide-angle design is the whole reason this model gets recommended, letting birders follow small, fast birds with ease
- ✓XD lenses with fluorite-rich ED glass deliver strong chromatic aberration control for a sub-$400 binocular
- ✓Outstanding 5.9 ft close focus makes it a legitimate dual-purpose bird-and-butterfly instrument
- ✓Bright, sharp central image - owners report identifying ducks and loons at distance and following birds in dark forest understory
- ✓Light for a full-size 10x42 at 22.8 oz with a well-made magnesium-reinforced body
- ✓Enough eye relief for most eyeglass wearers, per birder owner reports
- ✓Exceptional value: reviewers consistently frame it as delivering mid-tier performance at an entry-plus price, and one owner repurchased the identical model without hesitation
- ✓Kowa's warranty and repair service earn specific praise from owners who have used it
- ✗Edge-of-field distortion and softness are the explicit tradeoff for the huge field of view - critics note the wide view comes with visible compromises
- ✗Bench testing by a forum member flagged roof-edge diffraction artifacts and design compromises from the short focal length
- ✗Some owners have had to send units in for focus-slop repairs, pointing to inconsistent quality control
- ✗One hunting-forum user found the focus wheel uncomfortable and imprecise - handling opinions are split
- ✗Some chromatic aberration remains visible despite the XD glass, especially off-center
- ✗Made in China rather than in Kowa's Japanese factory, which surprises buyers who associate the brand with Japanese production
- ✗Not in the same brightness league as premium 10x42s in twilight conditions
- ✗Durability reports are mixed enough that some forum members recommend buying from dealers with easy return policies
Kowa BD II XD 10x42 vs Kowa BD III XD 10x42: common questions
What changed from the Kowa BD II XD 10x42 to the BD III XD 10x42?▾
Mainly the body. The BD III keeps the fluorite-rich XD glass, 378 ft field, 5.9 ft close focus and 16.5mm eye relief, but weighs 21.5 oz against 22.8 and is a little shorter. It has a magnesium body but no locking diopter or tripod adapter.
Should I worry about quality control on the Kowa BD II XD 10x42 or BD III XD 10x42?▾
BD II owners report some units needing warranty repair for focus slop, though Kowa's service earns praise. Nothing yet shows whether the BD III fixed that, so buying either one from a dealer with an easy return window is the sensible hedge.