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Eight 8X reverse porros compared (1 Viewer)

I wasn't going to buy any binoculars stronger than 7X, for three reasons. First, I had thought they'd be too hard for me, at age 66, to hold steady. Second, I had thought their eye placement would be finicky except for models with 30mm objectives. And, third, I thought they'd bee too dim, given that reverse porros are limited to objective lenses of 30mm or smaller.
But various posts changed my mind about these reservations:
  • One member described a way to brace the binoculars against one's eyebrows.
  • A second member--or an Amazon reviewer--described how to steady one's hold by interlacing the fingers above the binocular.
  • A third person posted about how large eyecups can make it much easier to avoid blackouts. I could--and did--replace the eyecups with larger cups or simply slip larger cups over the existing cups.
  • Numerous members wrote that a compact reverse porro--at least, one with newer multicoatings and large BAK-4 prisms--could be as bright as a larger roof-prism.
Once I bought my first excellent 8x25, there was no turning back. Beyond being easy to eyeball, a good 8x24 or 8x25, when fitted with large eyecups, can be almost as easy to eyeball as a good 6X or 7X compact.

As I grew familiar with each model, I tested it, through numerous tweaks, on three DGK Color Tools color test charts, placed at about 4 meters, 6 meters, and 7.5 meters. I also took each on a walk around the neighborhood, using it to try to read street signs and a pond's "No Swimming" sign from various distances. Unless noted, each 8X model has an aspheric lens and a field of view between 6 and 6.5 degrees.

Incredibly, I was able to buy five of the eight models as New Old Stock (NOS).

Here are the eight 8-power models I bought and tried:
  • 8x23 Bushnell 13-8023 Aspherical ($29 shipped, used, U.S. eBay). With the word Aspherical as part of its name, could this Japan-made Bushnell be a sleeper? For just $29, I decided to find out. In a word, No. This model was my greatest disappointment. Incredibly hard to focus, with too little detail once you achieved focus. Don't waste your money.
  • 8x24 Pentax classic/vintage ($58 shipped, used, U.S. eBay; designed and made in Japan). This is a chisel-edged, old-school design from the 1960s, with large prisms, a highly holdable shape, and a large (22mm), perfectly-damped knurled focusing ring marked "8 X 24 6.5° Pentax Japan. " It has no aspheric elements. But someone on an astronomy site had raved about its pinpoint focus, so I was hoping it was a hidden jewel. Maybe it would be if it were new in box. On my specimen, age had taken its toll. The right ocular had jumped its track and the view was among the least bright, least contrasty of all the models I tested, from 5X to 10X; it was as though the eyepieces had cataracts. The resolution seems to be there, but without contrast, using this bino brought me no joy.
The next three models were made by camera makers. As luck would have it, I nabbed each as New Old stock (NOS) at a bargain price. Optically and ergonomicallly, they're so closely matched that my advice is to grab whichever one comes up for sale. None is particularly bright, but you don't really notice until you gaze into a dark closet, as I did, and immediately test a brighter 8X model, like the Swift Micron or the Nikon Mountaineer II. All three use twist-up eyecups. And on all three, the eyecups have lips, about 1.5 or 2mm deep, that rob you of space for your eyelashes. I cut away the lips from the Pentax and and Minolta; I left it on the Olympus so that at least one of three would remain unmutilated.
  • 8x24 Pentax UFC G ($97 shipped, new old stock from a Japanese seller on U.S. eBay). I chose this model over the better-known, sexier-looking UFC X or X II because the the G was the last Pentax reverse porro that was made in Japan, suggesting that its manufacturing cost was secondary. While not quite as bright or "friendly" to use as my best 8x25 reverse porros, the UFC G makes up for it with tremendous resolution and three unusual features: First, its right-eyecup diopter is adjusted by a dedicated wheel centered between the left and right cup. You simply can't dislodge your right-diopter setting by accident. Second, the unibody design, shared by earlier and later Pentax models, helps ensure that the two barrels stay aligned. And third, there's a tripod mount, a rarity in this class. The body isn't very grippy, so I applied grip tape along the top and bottom. And the plastic twist-out eyecup inner lip (flange) intruded on my eyelashes, so I cut it away and sheathed the stock eyecup with BoliOptics 30mm Microscope Rubber Eyecups. The focusing knob is on the small side and highly damped; moreover, the view snaps into focus rather than easing in. As a result, focusing took some care. But my patience was rewarded with jaw-dropping resolution, certainly more than I had thought possible from an 8x24. And I think the magnification is more like 8.2 or 8.25. Is the Pentax UFC G in my top three? Overall, no. Optically, maybe.
  • 8x25 Minolta Activa FM ($66 shipped, new old stock, U.S. eBay). Introduced in 2001, the Activa FM was the pinnacle of Minolta's compact-bino glory days. Though made in China, it was the company's only reverse porro to feature full multicoating, large eyecups, and long (18.5mm) eye relief. I don't wear spectacles, so I'll have to take them at their word. Focusing can be slightly touchy. While the large oculars were a plus, their generous outer diameter was nullified by the same 1.5-2mm inner lip until I cut it away. I also made the wider eyecups even wider by fitting them with some cheap 34mm microscope rubber eyecups.
  • 8x25 Olympus PC 1 Tracker ($48 shipped new old stock, U.S. eBay). Everyone raves about the Tracker's resolution, but I found it no more resolving than the Pentax and Minolta. That said, The Olympus probably the brightest of the three. (It's not as bright as the Swift and Nikon 8X models.) Its biggest advantage is its size: You could almost carry it everywhere in your trouser pocket, especially if you kept it sealed in a sandwich bag. Its biggest drawback is its diopter dial, which goes out of adjustment if you so much as look at it the wrong way. On all my binos, I've marked my diopter setting with a Flymax white paint marker.
Now we come to my two favorites in this roundup. These models convinced me that I prefer binos that "ease" into focus over binos that snap into focus. The Minolta, Olympus, and Pentax has a sharpness that bites. But thee sharpness is more fleeting, a nudge away from being lost. The Nikon and Swift gain and lose their sharpness gradually, and it's more holistic. It's rather like the difference between a Tessar lens, which gets sharper in the corners as you stop down the iris, and a Sonnar lens, which gets sharper all over.
  • Nikon 8x25 Mountaineer II, also sold as CF-WP RA II ($122 shipped, new in box, from Japan on U.S. eBay). I almost didn't buy this model, for two reasons. First, there were none to be found for my first three months of looking. And second, at least two owners had written that the Nikon Prostaff ATB (aka Travelite EX) was better optically, with better coatings. Then I reread the threads, and there seemed to be something special about the way it felt in the hand and the view it delivered. On top of that, one former owner said, almost off-handed, that the Mountaineer II was closer in magnification to 9X. I had to try to it. Am I glad I did. Its devotees were right about everything. Its most magical feature is its ease of focusing. With a heavily damped 25mm ridged focusing wheel and tremendous focus travel, I can adjust my focus point with surgical precision. Moreover, the depth of field is high, and the 3-D pop of objects at different distances belies the reverse porro's close-barrel design. The magnification does, indeed, seem to be 8.5 or 8.6X. Yet the field of view is wider than any of my other 8X models. And the view has brightness to spare There's just a lot of magic in this model. Drawbacks? Two: It's heavy, at 450 grams. And it is vulnerable to veiling glare at the objectives end and to light leakage at the ocular end. I've neutralized the light leakage by fitting the 38mm eyecups with standard-size Eyeshields from Field Optics Research. The eyeshield do require a few more seconds to fit the bino to my face, but they seal out the sunlight, adding contrast. Among my 8s, it's the only model that's shockproof, waterproof and gas-filled.Other models come and go from my "two favorites" list; the Mountaineer II remains king of the hill.
  • Swift 8x25 Micron 805R ($34 shipped, new old stock, U.S. eBay). Made in Korea, the Micron 805R was the successor to the 805, adding a rubber grip, though I suspect the R stands for revised, not rubber. The Micron has the closest focus of the bunch, about 8 feet. It also has the most relaxing view, more like a 6X or 7X. There's nothing bad about its folding rubber eyecups, but I made a good thing better by wrapping them with BoliOptics 30mm Microscope Rubber Eyecups, allowing the Swift to rest more firmly on my face. At 11 oz., the Micron is a bit lighter than most. The ergonomics are just outstanding, with a 22mm heavily damped focus wheel, a shape that falls naturally to hand, and a texture that's just right. It breaks my heart that most of you will never get a chance to try it. The only one for sale that I've seen worldwide is the one I bought.
  • Bushnell 8x30 Off Trail ($40 shipped, used, U.S. eBay). If you want a 30mm reverse porros, it's slim pickings. There are some cheap 4x30 and 5x30s, old and new. I don't know of any 6x30s or 7x30s. When you get to 8x30, there are maybe five models: (1) Bushnell NatureView (the NatureView Plus was made in 10x30 only); (2) Bushnell Off Trail 13-3008, a fully coated model that might be the same as the Sanju MC3; (3) Bynolyt or Optovision, whose color will be off because of a UV filter; (4) Baigish "8x120," which I ordered from Amazon as the "DOT-01" but never arrived; and (5) Nashica MC-CMR (fully multicoated, Bak-4), a current model that's probably the best of the bunch. I think all have a field of view of 7.5 or 8 degrees. I don't recommend the Off Trail. It seems to be from 2008 or older. Its close focus isn't close (5 meters or 16 feet, as I recall). The view was uninspiring, with lackluster brightness and contrast and only average resolution. Like all the 8x30s, it's quite a step up in volume and weight from a typical 8x25. (I think that in a porro, weight and size begin to scale disproportionately as soon as you exceed 8x26.) The only good thing I can say about it are that the view is comfortable, almost relaxing, in part because of the 64-degree apparent field of view.
There you have it. If I were to die with one 8X bino in my hands, it would be an 8x25: either the Nikon Mountaineer II or the Swift Micron: they require fewer compromises while providing more physical comfort and visual joy.

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