Binoculars: Sense, Nonsense and Science

I work as a towboat skipper in the country’s inland waterways. Binoculars piqued my curiosity since I use them at work. Years ago, I opted to purchase my own binoculars since the ones provided by my employers were “barely-get-bys” on the river.

After much research, I determined that the best binocular for my needs was the post-war commercial 750 Bausch & Lomb. This binocular, complete with case, would have cost about $300. This was a community that a 23-year-old with three children and a pregnant wife couldn’t even afford to visit, much alone purchase in.

I started looking elsewhere. In the autumn of 1963, I acquired a Swift 750 MKII, centre focus, with 84.2 light transmission. A local surplus shop ordered it for me for $10 more than the cost, bringing the total to about $75. I have not looked at any 750 binocular that is noticeably superior for my needs. My fascination with binoculars started with a drive to discover a better binocular. For the record, the MKII is a B&L clone produced in Japan. It has the same frame type, BK-4 prisms, magnesium alloy frame, magnesium fluoride hard coating, eccentric collimating objective cells, and so on. The only difference is that it is in the middle of the frame. Individual emphasis is not required since all of my job is done inside.

The B&L-style porro prism binocular is still by far the greatest construction technique. It was originally available in 1931. Bausch & Lomb and other manufacturers have produced millions of them since then. Durability, performance, depth perception, and simplicity of cleaning and maintenance are all advantages of this sort of construction.

I understand that some will overstate all of the existing benefits of other styles:

  • Prisms on the roof. This style was popular before to World War I.
  • Optics with several coatings. This was invented by the Germans in the 1940s.
  • Lightweight. During WWII, the Germans employed Bakelite for binocular frames, whereas the Americans used plastic.

To be sure, there are presently polymers (plastics) that are lighter and less subject to temperature fluctuation. There are additional sophisticated multicoatings that promise to transmit more than 95% of light theoretically. The cost of these improvements is never justified by an increase in performance. Typically, this improvement is approximately 5-10% and is only evident around 5% of the time you use the binocular. Only one new benefit has been added: eye relief.

For people who wear glasses, there have been significant advancements in eyepiece design, as well as fold-down eyecups. However, for people who do not use glasses, this eyepiece design results in a reduction in clarity and resolution. The majority of these designs date back over forty years. So, what makes sense here? Considering purchasing a new binocular for much over $1,000, or looking at antique binoculars? I believe a closer look at the latter is in order.

Until the mid-1950s, the only options on the US market were surplus military binoculars and new B&L and Zeiss Jena models. The only exceptions were certain French binoculars, which were mostly rubbish. The B&L and Zeiss binoculars, as well as secondhand military binoculars, were prohibitively costly.

Dave Bushnell created his Featherweight brand of binoculars in the early 1950s. His marketing efforts, as well as the employment of a competent optical guy to oversee research, Al Akin, propelled him to the forefront of the hundreds of new importers. Bushnell was simply another importer until it began doing its own research and developing a stringent quality-control regime. Bushnell sold glasses with optical quality equivalent to B&L and Zeiss for one-fourth the price. He also debuted the Rangemaster with a broad field of view. Neither B&L nor Zeiss produced a similar model.

Other importers started producing better glasses after learning from Bushnell. They worked with the greatest Japanese businesses to accomplish this. As a result, we now have Sears, Western Field, Burton, SPI, Swift, Tasco, and Selsi-branded glasses from Fujinon, Kowa, Ofuna, Asahi (Pentax), Topcon, and Zuiho.

Importers have three unique lines in the binocular hierarchy:

  • Good – It had a Zeiss-style frame, but it wasn’t totally coated—what I call a “barely get by;”
  • Better – A decent binocular with a B&L-type frame, aluminium vs. magnesium alloy, BK7 prisms vs. BK4 prisms, and completely coated lenses is usually better.
  • Best – Top of the line, featuring cutting-edge technology.

Wide-angle spectacles, which were formerly exclusively available in the Better and Best categories, were traditionally the most costly. Because of the intricate ocular lens assembly and bigger prisms, this was the case. The binoculars to look for are the “Better” and “Best” in each line. Flea markets, yard sales, pawn shops, and auctions are all places to find them. Prices vary, but they are usually always less than $50. Be cautious while purchasing since cleaning and maintenance fees may add up quickly.

What power should you check for while looking for antique binoculars? This is primarily determined by how you want to utilise them. To be more specific: 750 for maritime usage, 735 for outdoor activities, and 830 for hunting and birdwatching. I read an essay about binoculars in an issue of American Rifleman from 1928, and I agree with the author that a 630, 735, or 830 would enough for most individuals. The 630 B&L-type porro centre focus is my particular fave. Despite the military’s preference for individual attention, centre focus is more practical. Individual attention is not required until you are heading into fight.

Some would claim that antique binoculars are impractical for a variety of reasons. Some arguments are legitimate, while others are ridiculous.

  • Nonsense Argument #1 : You must have multicoated lenses. If you look at the objective—or big—end of today’s binoculars, you’ll discover that part of the glass is green, some blue, some orange, and even some red. The colours of magnesium fluoride coatings may vary depending to thickness. These hues have no effect on performance.
  • Nonsense Argument #2: Today’s technology is significantly superior than that of antique binoculars. The use of multicoatings, which enabled the fabrication of eyepieces with very long eye relief, and low-dispersion glass offers benefits. However, this is only done on rare instances. In the previous 75 years, the optical principles and designs of the eyepiece—the heart of each binocular—have altered little. Some of the earlier versions are more stylish than what is available now.
  • Nonsense Argument #3: New building materials have rendered aluminium and magnesium alloys obsolete. Although there are many unusual petroleum-based synthetic materials available, the advantage solely benefits the maker. He or she benefits from easier machining, lower material costs, and less labour. These glasses are not as well-made as vintage glasses. This becomes clear when you attempt to locate someone to fix them. Some manufacturers ask that all defective glasses be returned to them. Typically, these glasses are tossed and replaced.

However, weight is a legitimate argument. However, little weight comes at a cost: inferior optical quality, performance constraints, and reduced durability. If you can afford to change your binoculars on a regular basis and weight is a consideration, this style of binocular may be the right choice for you.

Since the invention of binoculars, the human eye and its capacity to see have remained unchanged. Not all eyes are created equal. What you see via a binocular is a union of the eye, the muscle that controls it, the brain, and its interpretation of the signal sent by the eye and received by the binocular. The binocular will not solve any issues with colour recognition, definition, depth perception, or astigmatism. Exercise benefits the eye muscles; for example, enhancing night vision requires spending more time in the dark, and boosting definition requires having your eyes work harder.

These results have been reached after forty years of observations. I have the benefit of having examined hundreds of antique and contemporary binoculars. I’ve also dismantled and restored a lot of things.

So, the next time you see a binocular ad touting exotic materials, superior pine tree-green coatings, lighter-than-a-breath-of-fresh-air construction, the pinnacle of scientific advancements, and 99.9% light transmission, keep in mind that advertising are paid to develop commercials that sell binoculars. With this in mind, you, the customer, must make a choice. Never buy a binocular without first testing it out. Best wishes!

“Binocular Bill” Beacom is a member of an international binocular enthusiast group, collects information on optics, and owns some 700 binoculars.

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