Kowa Prominar BD32 Binoculars

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Review Highlights Kowa’s mid-priced 32-mm binoculars, excellent optics on a budget Crisp, bright image quality – BaK-4 glass, fully multi-coated, phase-coated and waterproof Huge field of view; great close-focus capability Compact and lightweight – fits in a backpack

Full Review

The Prominar BD32 binoculars are a new line that came out at about the same time that Kowa re-issued the BD42 binoculars, and they are another entry into the increasingly hot 32-mm binocular market. Many optics companies are producing high-quality, mid-size binoculars, and it’s easy to see why they are popular. They are lightweight, compact, and with today’s coating and glass technology, the fall-off in brightness in going from 42-mm to 32-mm objectives is barely noticeable, particularly with the mid- to high-priced range of products. At just $485.00 for the 8x and $510.00 for the 10x, the Kowa BD-32 binoculars are low in the mid-price range, while providing performance decidedly above that level.

Size and Weight

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At first glance, the BD-32s are just a smaller version of their 42-mm cousins. Like the BD-42 models, these are roof prism binoculars, fully sealed and nitrogen-purged to be waterproof, dustproof and fogproof. And like the BD-42s, these feature the same advanced C3 coatings and Schmidt-Pechan prisms. The reduced dimensions on the BD32s are 5.1 inches tall by 4.9 inches wide on the 8x model while the 10x version is 5.2 inches tall by 4.9 inches wide. These binoculars have an interpupilary range of 58-74 mm, about average for a mid-size binocular. Both models of BD32s weigh just 20 oz., so you won’t suffer much fatigue lugging these around all day! They are forest green with black trim. Like the 42-mm version, the BD32 binoculars are roof prisms, fully sealed and nitrogen purged to be waterproof, dustproof and fogproof. The BD32s also feature the same high-quality BaK-4 glass as the BD42s.

Focus and Field of View

A closer examination shows that there are substantive differences between the 32- and 42mm models. The differences are in things like field of view at 1000 yards, minimum close focus, speed of focus, and eye relief. The BD42 binoculars had excellent field of view in both models. The BD32s improve on this. The 10x BD32 model has the same 341-foot field at 1000 yards as the 10x BD42, but the 8x BD32 has a 426-foot field at 1000 yards, which is excellent performance in this regard. We measured the minimum close focus on both BD32 binoculars at just 4 feet, which ought to catch the attention of the butterflying crowd! While the BD42 binoculars went from minimum close focus to infinity in 1.33 turns of the focus knob, the BD32s do it in just 1.25 turns. The focus knob is physically identical in both binocular lines, meaning that it’s proportionally larger on the mid-size BD32s, with accordingly better ease of use. Only in eye relief do the BD32s finally act like a smaller binocular: 15 mm for each model. This is only to be expected though.

Adjustable Features

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One other substantive difference is in the eyecup adjustment mechanism. The BD-32 binoculars come with two full stops between fully-in and fully-out positions for the eyecups. Both intermediate positions are held by very firm detents, so they do not collapse unless you deliberately twist the cup. We see a lot of helically adjusting eyecups; very few of them work as well out of the box as these. The diopter adjustment mechanism is of the most basic kind. Diopter adjustment on the BD-32 binoculars is a ring on the right ocular tube that twists in either direction. The mechanism is deliberately stiff to prevent accidental slippage, and the position for equal focal depth of both ocular tubes is marked by a raised line that aligns with markings on the adjustment ring. The mechanism is serviceable enough, but lacks sophistication. This kind of mechanism is fine for people whose eyes use the equal position setting, but it’s more difficult for those whose eyes require unequal settings. The lack of a locking mechanism or of any markings to indicate settings for unequal eyes prevents us from giving Kowa full marks on this property.

Optical Performance

When it comes to optical performance, the Kowas continue the pattern of high achievement at low cost. The BD-32s show very little in the way of edge effects. There is little to no inward curvature of straight lines at the edge of the field, though we did notice a tendency for field edges to go blue when viewing brightly lit objects. This kind of color aberration is not particularly uncommon, and we did not notice any other sort of color bias to these binoculars. Instead, the images were consistently bright and very sharp.

Covers and Case

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Kowa BD-32 binoculars come with a fairly standard rainguard: two rubber cups linked by a flexible tether region that attach to the strap with a solid bracket on the left side and a gapped bracket on the right. Our only quibble with this is that in this case, the rainguard does not fit very snugly over the ocular lenses, with the result that it is fairly easily dislodged by the merest touch. The objective lens caps are rudimentary: a pair of hard plastic cups that fit quite snugly in the flexible rubber armoring of the barrel ends. These appear to be designed more to protect the lenses in the case, but not for use in the field. The case is a padded leather pouch with a Velcro closure that fits the binocular easily with the eyecups down or snugly with them up.

Conclusions

So how does one sum these binoculars up? Words like “great value” come to mind, since the performance is equivalent to many much higher cost binoculars in a binocular that is lighter, smaller and significantly cheaper. As noted, there are things that Kowa could have done better, but most of these don’t impact the one critical area where they have done well: optical performance. In short, these are fine little binoculars that really are a great value, and we like them a lot!

Kowa Prominar BD32 Binoculars - current price and availability