Kowa BD 8x42 binocular

Highly respected and with a well-established niche in the telescope market already, Kowa now seems hungry for a bigger slice of binocular sales. Earlier this year it upgraded its six-year-old BD series – the new 8x and 10x magnification in both 32 mm and 42 mm objective models now comprise half of its relatively narrow binocular range.

Despite the BD’s very similar outward appearance to the old models, there are a number of subtle external distinctions. However, the principal differences between the two are to be found internally, in the form of new and improved multi-layer coatings and advanced, re-engineered mechanics.

The same metal body construction means there is no change in weight between this model and its predecessor. The balance, however, is excellent and I found the generous – though shallow – cut-away thumb rests were perfectly positioned for my hands. The body is otherwise smooth and unribbed, and the green rubber armour is relieved only by a toughened black polymer ‘bridge’ across the hinge, which bears the manufacturer’s name unobtrusively in silver. This rubber body armour is a new material that is softer and grippier, without the old model’s harder, almost slippery feel. There is a good depth of rubber extending beyond the objective lenses, which will absorb impact if the binocular is dropped.

Black eyecups add further contrast to the green body. Their construction is also much improved – the dust-collecting soft rubber of the old model has been replaced by a smoother, firmer material and they can now be twist adjusted to lock in no fewer than five different positions, instead of just the fully closed or fully extended options offered previously.

The dioptre, which is built into the right eyepiece, turns smoothly. Other than two arrows inscribed with + and -, there is no increment scale or lock, although it offers enough turning resistance to remain in position once the adjustment has been made. The general focusing wheel marks another improvement over the old model, turning much more smoothly, and taking just over one and a quarter turns from close focus to infinity.

I measured the close focus at 2 m – the manufacturer’s quoted figure – but to my eyes there appeared to be some ‘tunnel shadowing’ around the edges of the image at this distance, disappearing when the focus was adjusted beyond about 5.5 m. The depth of field appeared good, without the need to constantly refocus, and the field of view – 110 m at 1,000 m – is at the expected level for an 8x42 roof-prism model in this class.

Kowa has done much in its attempt to improve the image delivered by this binocular. Its Schmidt-Pechan prism system – widely used in top-of-the-range binoculars – has been further enhanced by the application of the new ‘C³’ highly reflective di-electric multicoating, which “allows for a much higher reflectivity”, reportedly reducing light loss and providing brighter and sharper images.

At first sight the results are pleasing. The image is certainly sharp and bright, the colours well-balanced and the overall tone neutral, with reasonable contrast producing a very true-to-life impression. It lacks peripheral definition, being a little soft at the edges, and there is a fraction more colour fringing than I would have expected to have seen, but this was by no means disconcerting and it did not significantly detract from performance in the field. Viewing birds close to the sun, or on water where there was considerable bright light reflection, did result in some degree of ‘flare’ into the field of view but, again, this never became a major issue.

I felt comfortable with both the physical and optical attributes of this binocular. It is easy to use and is now supplied with a neoprene-padded strap as standard – another improvement over its predecessor. Nitrogen filled and waterproof, this is another model which makes low- to mid-range binoculars more attractive by providing another credible alternative to high-performance products at the top of the range for a fraction of the cost.

The selling price for this model has increased only marginally since last year, but the improvements which have been made to the BD range certainly warrant it.