Price: £896 (8.5x44); £970 (10.5x44)
Size: 165x138 mm (both)
Weight: 950 g (8.5x44); 965 g (10.5x44)
Field of view (m at 1,000 m): 122 m (8.5x44); 108 m (10.5x44)
Close focus: 1.7 m (both)
Gas-filled: yes (both)
Waterproof: yes (both)
Guarantee: 10 years (both)

If the top end of the optics market needed a shake-up, Kowa has stepped in to provide one. Hot on the heels of its flagship fluorite crystal 88 mm telescopes, the TSN-883/884 (see Birdwatch 174: 44) comes the XD44 series binoculars, which use the optical technology of the TSN-880/770 series scopes with Prominar XD lenses.

Launched in February this year, this new series follows the trend of the latest roof-prism binoculars to feature larger objective lenses – in this case 44 mm – and increased magnification, to 8.5x and 10.5x. This aside, these very understated binoculars will win no prizes on the catwalk of optical aesthetics. Essentially two smooth, uncontoured, green rubber-armoured barrels linked by a hinge and central focusing knob, they are uninspiringly plain and would completely lack identity were it not for the small Kowa logo on the distal hinge cover. Anyone would think Kowa is intent on keeping its new baby a secret, but closer inspection reveals the Prominar brand epithet inset along the left barrel.

It is difficult to imagine why the XD44s have made their debut almost incognito. Could it be their weight, perhaps? Just short of a kilogram, they are the heaviest performance binoculars on the market and, at a time when optics manufacturers are placing an emphasis on weight reduction, it seems strange that Kowa appears to be bucking the trend with these models. But another Japanese manufacturer has done something similar: having introduced a series of models widely recognised as being ‘too heavy’, it rapidly reduced their weight by 20 per cent and released a ‘lite’ version within a year of the launch of the original models. Perhaps history will repeat itself.

What the XD44s may lack in style and agility, they make up for in performance. Despite being fairly heavy, they are perfectly balanced when held for viewing. The usual niceties of nitrogen gas filling, virtually indestructible barrels and an ultra-close focusing system, taken for granted in contemporary binoculars, are all present here. Soft but firm rubber eye-cups click-stop in four different positions to vary eye relief, although if you want to operate the dioptre, you have to position the cup on the right barrel at one level above the base setting. I found the single-eye focusing mechanism very sensitive in terms of reaching the correct setting and achieving parity for my eyes.

The central focusing knob is generously proportioned, allowing a comfortable two-finger contact to be made with the high-friction surface. In the two models I tested, there appeared to be a considerable difference in how freely the knobs turned (the 8.5x had a smoother action), although this may be the result of variation between the individual instruments. In just under 1.5 turns the focusing ranges from close-up to infinity in both models, but I found a discrepancy between the manufacturer’s close-focus figure of 1.7 m for each model and the figures I achieved, which were closer to 1.8 m for the 8.5x and 2.0 m for the 10.5x.

A positive feature of the focusing is the admirable depth of field. Switching from objects which are in focus between 4 m and middle or long distance to distant horizon takes a quarter turn of the knob on both binoculars, although the depth of field is not quite as great on the 10.5x model.

The field of view for each is close to those of other top-flight models on the market. Given the ‘extra’ 0.5x magnification of the 10.5x, the 108 m field at 1,000 m is excellent, but the equivalent 122 m for the 8.5x is perhaps a little lower than might have been expected.

The image itself did not fail to impress. The colours, contrast, sharpness and brightness are excellent, and in this respect these binoculars are a joy to use. Their brightness alone – no doubt a combination of the high-quality glass in the lenses and the new prism system and coatings – propels them towards the top tier of optical excellence. With larger than ‘standard’ objectives gathering more light, the 10.5x magnification in combination with the 44 mm objectives provides the same exit pupil as a 10x42 binocular. I particularly liked the extra reach provided by this magnification compared with the currently popular 8x magnification. In poor light conditions (dusk at a busy mixed Common Tern and Black-headed Gull colony) both models performed incredibly well, utilizing what little daylight remained to produce an enhanced image. To my eyes, there was no significant difference between the two in terms of brightness.

Other aspects of the image include a bluish colour cast, producing a generally cold tone, and a minimal degree of chromatic aberration. Although detectable, the latter is restricted to the periphery of the image, where the curvature of field is similarly nominal and the reduction in sharpness is negligible.

There is no doubt that these two models are excellent. Although the XD series is competitively priced compared to other top-drawer binoculars, it seems likely it will have to overcome its weight problem before ‘Kowa power’ fully penetrates the highest echelons of binocular supremacy.