Alpen Pro 8x25 Binoculars
There are certain circumstances when a compact or "mini"-binocular is very useful, as a back-up optic easily stowed away in carry-on luggage or a glove compartment, or when birding with a younger birder for whom a heavier optic would be uncomfortable. Alpen offers a full range of mini-binoculars in their Pro line, from 8x25 and 10x25 wide-angle models to 8x, 10x, and 12x25 long eye relief (LER) compacts. We looked at only the 8x25 LER compact, and here's what we thought.
Like most compacts, these feature a reverse porro-prism design. Such designs usually cannot be sealed or nitrogen-purged, and hence, they are not fog- or waterproof. The Pro 8x25 LERs are made with BAK4 glass and are multi-coated to optimize resolution and light transmission. This particular model has a 314-ft field of view at 1000 yards, just about average for a mini. (The wide angle, 8x25 version is listed at a very respectable 430 feet!) On the other hand, they also tested to a quite impressive 64-inch minimum close focus, which is excellent for any optic. This means that this mini might appeal to the butterflying crowd too. The Alpen Pro 8x25 LER compact has 16 mm of eye relief, longer than the 11 or 12 mm typical of mini binoculars as a class, but matching other minis with long eye relief..
Focus is adjusted with a centrally located knob that is partially recessed in the hinge region between the barrels. The adjustment from minimum focal distance to infinity is achieved with 1-1/3 turns of the knob, but because only 1/3 of the knob circumference is available to the fingers, it takes a bit longer to deploy. Again, this type of performance is common to the mini-binocular genre, and by no means peculiar to the Alpen minis. The focusing knob is coated in pliable rubber armoring which improves traction and the mechanism is smooth and easy, even when new.
The eyecups are of stiff forest green rubber, and adjust with a counter-clockwise twist to a fully extended position. There are significant detents at the fully-in and fully-out positions. Hence, this is truly a twist-and-lock system, but there are no intermediate positions possible for the eyecups. The diopter adjustment mechanism is simple: a hard rubber ring on the right ocular twists in either direction to adjust. The even eyes position is marked by lining up a raised flange on the ring with a notch on the right barrel, but there are no notches on either the ring of the barrel to mark other positions. Thus, for users whose eyes are not equal, the "correct" position must be etched in by hand or re-adjusted each time it shifts or is lost. There are black, hard rubber caps that fit snugly over the eyecups to protect them during storage. These work quite well.
At just 11 oz., the Pro 8x25 LERs are feather-light! The widest part of the barrels is coated in pliable green rubber armoring which helps the grip but probably does not provide much cushioning if they are dropped. Nice little ridges on the barrels act like thumb grooves to help position the hands. The rest of the outer housing is slick black plastic. Like most minis, for people with larger hands, the issue isn't one of holding them steady. Rather, it's one of where to put one's fingers. The black plastic lugs for the strap attachment fall right under the fleshy web between the thumb and forefinger, so there is potential for this to chafe a bit. These aren't knocks against the Alpen Pro minis specifically – they are just consequences of the small size and design constraints of mini-binoculars in general.
In the field, the Pro 8x25 LERs are about as bright as a 25-mm objective lens is likely to be. They are great under moderate to bright light conditions, but notably less so as ambient light drops. The image quality is fairly good, with pretty sharp image quality, virtually no edge effect distortion, and no notable color aberration. We did note a slight mushiness to the focus at the edge of the field.
The nylon strap is about 1-inch wide in the portion that goes around the neck, which, combined with the negligible weight of the binocular, is comfortable enough even for a long day in the field. The 8x25 Pro comes with the same green and black nylon soft case as the more expensive Alpen models – it's actually a very nice case. The Alpen Pro 8x25 LER compacts can be had for $85.00. These may not be a top of the line birding binocular, but if the need is for a low-cost, portable, small-sized, back-up pair, or if you want something lightweight to interest a nephew or grandchild in a morning's birding, or to take to symphony hall for a great look at the orchestra, these fit the bill quite nicely.
The Alpen Pro 8x25 LER binocular can be seen here.