• Leupold BX-4 McKinley HD 10x42 Binocular

    The Leupold BX-4 McKinley HD line of binoculars is all new for 2013, and I just happened to be fortunate enough to get my hands on a 10x42mm example for evaluation.

    I should probably start off by noting that I am not a binocular expert - not by any means. In fact, when it comes to binoculars I generally have very little interest in them and they have only played a minor role in my 30 years of hunting and other outdoor activities.
    As such you shouldn't expect to find a lot of technical detail or an in-depth interpretation of specific technical aspects of the McKinley BX-4 binocular. What you will get is my real world opinions and thoughts of the BX-4 based on how they perform in the field and how they stack up against the binoculars I've been using for the past several years.

    The BX-4 McKinley HD 10x42 binocular has a current street price of around $600, and while that may seem like a lot to spend on a binocular the McKinley HD is really a bargain at that price when you look at the features and optical quality that it offers. The advanced HD lens system features extra low dispersion objective lenses paired with rare earth element coated ocular lenses for superior color rendition and razor sharp resolution. The twist-up eye cups and long eye relief make the BX-4 McKinley binocular easy to use with or without glasses while also eliminating glare and other problems on bright, cloudless days. A large, tactile focus dial is easy to find and use, and gives you the precision focus you need to pick antlers out of the trees or hide out of the brush. Other features include Leupold's proprietary nitrogen-fill process and a 100% waterproof/fog-proof construction, fully multi-coated lenses and BAK4 prisms.

    As far as specifications are concerned, the BX-4 McKinley HD 10x42 offers a linear field of view of 336 feet @ 1,000 yards and an angular field of view of 6.40 degrees. The interpupillary distance is variable from 56mm to 74mm, the exit pupil measures 4.20mm, and the eye-relief is listed at 20mm. Overall length is 6.10 inches and claimed weight is listed as 29.0 ounces.

    Optical Performance

    The first thing you'll notice when looking through the BX-4 McKinley HD 10x42 is that the sweet spot is huge. While the sweet spot of most binoculars generally consists of the middle 40-50% of the field of view, the sweet spot in the McKinley HD easily accounts for 70-80%. Even when the flatness and sharpness of the image eventually starts to degrade in the outermost 15-20% of the BX-4's field-of-view it's so minimal that you really have to look hard to notice it.

    With such a large sweet spot the sharpness of the image provided by the BX-4 McKinley HD is equally impressive. While most quality modern binoculars are capable of delivering more detail than our eyes are capable of processing, I like to believe that even an untrained eye can pick up on when a given binocular is "less than sharp". Beyond that, some binocular models are capable of delivering an image which makes us feel as if we are seeing as much detail as is possible...and then even a bit more, and the McKinley HD falls into that category.

    The brightness of any optic generally tends to be subjective, even in laboratory testing where the results can vary greatly depending on the range of the spectrum of light being measured through the optic. As such I generally don't pay much attention to the manufacturers claims and instead base my results on how well the optic gathers light in real world low-light conditions. In the case of the BX-4 McKinley HD I was unable to find a low-light situation during legal hunting light where it failed to provide more than sufficient brightness, and in many instances continued to perform admirably well beyond legal hunting light.

    One area many binoculars have an issue is when it comes to color bias, and this can occur for a number of reasons, but the McKinley HD seems to have little to no apparent bias to speak of. The contrast also seems to be excellent with blacks and whites almost jumping out from one another when in contrast with the surrounding space.