The larger 8×56 specification is the leading choice for hunting in low light situations when compact low weight can be sacrificed for the ultimate bright image. A 14mm increase in objective diameter from 42mm to 56mm seems just a 33 per cent increase in physical size, yet a 78 per cent increase in surface area for the objective lenses to accept more light entering the tubes and present to your eyes.
Leica’s 8×56 HD-B binoculars with HD glass, incorporating the latest chemistry and coatings, promise to transmit 90 per cent of that light to your eyes and, when combined with excellent ballistic technology, may just be the best of both worlds. The overall size has been kept relatively modest, an increase of only 9mm in height and 20mm in width over the current 8 or 10x42mm HD-Bs. The unit shows the distinctive curved tubes surrounding the Abbe-Koenig prism layout, yet melts easily into the grip of your hands and eyes, belittling its initially bulky appearance.
At 1200 grams, the magnesium chassis shows neutral balance, the eyecups lock the unit into your orbital sockets, and extended scanning or ranging is superb. Six positions are available for eye relief adjustment on the rotary eyecups, and they have strong detents to maintain your chosen position, too. Clear image contrast is assured by baffling within the tubes to minimise any stray light bouncing around, offering sharp edge-to-edge clarity across the entire field of view that’s flat and sharply focused in all areas. With a twin bridge design, smaller hands wrap comfortably around the rubberised grippy tubes, with fingertip control of the central focusing knob from 4m to infinity available in 1½ revolutions. It carries ribs along its 25mm length, and there is a slightly dampened feel to its well-weighted and precise rotation for viewing with sharp focus when chasing details, yet a decent depth of field when scanning broadly.
Rubber lens caps slip over the 8mm overhanging armour at the objectives and these can all too easily fall off, so I have fastened those on my own HD-B unit with electrical tape for semi-permanent security. Both eyepieces show individually, and are similarly shrouded with a rubber lens cap set slung from the neoprene neck strap, the lugs for which emerge from the armour far enough back and low enough in profile so as not to dig into your knuckles.
The internal LED display requires ocular focus on both eyes running from +/-4 dioptre on the HD-B’s, set by a collar at the base of of each eyepiece. They remain solidly in position once set and are simple to alter for different users. Eye relief has six setup positions from the telescoping tubes for changing positions in the field, and is a joy for either spectacle wearers or the naked eyes, with soft radiused cups perfectly proportioned for my eye sockets and which, at their longest setting, can be unscrewed for thorough cleaning. Leica’s AquaDura external coatings promise rainwater and dirt will shed more quickly, and I certainly had no complaints, but heavy mud fouling or the like should always be cleaned very carefully.
The HD-B’s ballistic program is controlled by buttons on the right rear bridge of the body. The upper is the main activator with gently convex surface, one press illuminating the internal square red reticle for aiming (a red dot shows on the bottom right corner of this to indicate ‘Metres’ are selected, just in case multiple users are taking a look). A second press displays the distance to target. Holding it down in scan mode gives range readouts updated every second for moving targets, or for those small targets that will ‘pop out’ visually from a disrupted background when they reflect the eye-safe laser bean. It’s noticeably powerful and the maximum range capability of 1825m was no problem at all on reflective large surfaces, I rarely got a failed reading, and repeated targeting of the same object at 873 metres gave me the same reading within +/- 2 metres each time. Any rangefinder will be affected by light conditions, visibility, and battery power though. It’s rated for 2,000 readings and an internal indicator will flash and warn you to replace the CR2 battery with plenty of notice if power starts to fade.
Range readouts take in 0.3 seconds, and 15 brightness levels of the reticle are automatically controlled to suit ambient light conditions. As well as taking the range into account, the HD-Bs will also measure shot inclination, temperature, and atmospheric pressure channelled into the ballistic calculator to further refine the shot solution. The figures can be displayed independently if desired by pressing the secondary button but, when fully up and running, their effect is internally incorporated, and you have no need to know what they are unless you are genuinely interested. In daily use at normal sporting ranges they are of negligible effect, but if you happen to be at very high or low altitude it is extremely important as most ballistics solvers will ‘ball park’ to approximate sea level, and the difference with the thin air in the mountains is significant at even modest ranges. Equivalent Horizontal Range is another factor that influences longer range shots or those at severe angles. The ABC computer calculates what long-range shooters call the cosine of the angle. If you imagine the shot distance the HD-Bs measure is the hypotenuse of a triangle, the angle of inclination is where the HD-Bs are most rewarding, a single tool to be held and used in one hand to make your single shot count at range.
Detailing the controls by a combination of the button presses within the HD-B’s menus is initially complex but, with patience, it’s straightforward to navigate through with an excellent manual included. There are setup preference US/EU options for Imperial versus Metric units (Yards/Fahrenheit/inHg or Metres/Celsius/Millibars), 12 basic ballistic setups for both MOA/Inch clicks on your riflescope or 5mm/10mm metric options. This can all be quite confusing, but with half an hour and some patience, everything soon works out. Using the ‘Card’ ballistic options requires you to place a MicroSD card into your PC via a supplied adaptor and going onto Leica’s website to use its ballistic calculator. For anyone who has used ballistic calculators before, it is a variation on a common theme and you can input information about your rifle’s performance and ammunition specification. Popular factory ammunition options are there, as well as the full ‘custom’ choice, where you supply your own details for ballistic coefficient and muzzle velocity to go alongside your scope’s adjustment units, and so on. For a device of this quality, it seems scandalous to me not to use the full custom route and the online program is fast and fairly self-explanatory – all you have to do is double check everything is correct and save the applied ballistic program to the SD card, taking about five minutes total. Getting the card in and out of the Leica’s battery compartment is a little bit fiddly, so take the battery out first to allow easier access to the port, which nestles between the two large front objective lens bodies.
The standard ballistic curves available from the HD-Bs allow correction out to 800 metres, while the custom option works to 900 and it assumes greater precision has been entered into the whole process. The reticle is unobtrusive and the data displayed of range, then correction with each click, is clear and simple. Where this binocular is perhaps of most advantage is where inclined shots up or downhill are taken and the image from the new 8×56 HD-Bs is undeniably brighter – but does that make it better when concerned with detail? With an everyday .243, .308, .270, .30-06, and a box of factory ammo at realistic stalking ranges, the standard curves will fit pretty much all requirements, but as ranges increase and kill zones get small, you do need to really refine matters to the best degree possible. Practice will always improve your skills.
That 8x versus 10x magnification choice is down to preference, experience, likely surroundings, hunting style and quarry species. One thing is for sure though, these new 8×56 HD-Bs are one hell of a binocular. Like all 56s, they show a few minor physical compromises to allow that unquestionably brighter image, but allowing greater perception of detail in low light for more time can overcome the lesser magnification by comparison to a 10x unit. I have recently tried the Zeiss RF binocular that can have its ballistic data input and altered via a smartphone and, nice as this is, I still preferred the functionality of all four pairs of HD-Bs I have used. That said, I suspect it’s only a matter of time until Leica must step up to a smartphone option.