The unexpected reason why I couldn’t focus easily
“Focusing through binoculars has become more difficult these days”, I thought to myself.
In my younger days, I could quickly and accurately adjust the focus of my binoculars.
Recently, however, it’s been harder to adjust the focus.
“I guess my eyesight is just getting worse with age”, I thought.
I had half given up on my aging eyesight until I got the Hinode 5×21-A+, which are low-powered compact binoculars with ED (Extra-Low Dispersion) glass.
I underestimated the effects of achromatic aberration.
Yes; achromatic aberration prevented me from getting a sharp focus.
I never paid too much attention to achromatic aberration.
Optical devices that use lenses can’t get rid of achromatic aberration completely, so I’ve always accepted it as long as it’s reasonably reduced.
However, as I’ve gained experience as an enthusiast, my eyes have become sensitive to even a little blurriness caused by achromatic aberration.
Certainly, my eyesight has become worse with age, but my eyes have become sensitive enough to detect these small differences.
You may assume that the simple solution would be to have more binoculars with ED glass on the market.
It’s true that some Chinese binoculars with ED glass offer excellent value for the money.
Compared with older pairs that used normal optical glass, I find much less achromatic aberration in the latest models.
However, ED glass is mainly used for large binoculars such as 8×42 and 10×42.
The larger the objective lenses and the higher the magnification, the more achromatic aberration will occur.
For this reason, even with ED glass, large binoculars still have some achromatic aberration.
When I borrowed a pair of Zeiss Victory HT 8×42, I got an image almost free from achromatic aberration. It also took much less time to focus on an object.
However, such flagship models cost as much as $3,000. That’s out of my price range; however, it’s still an exhilarating feeling to use such an expensive pair.
I’ve finally found a pair, besides Zeiss, that gives me an image free from achromatic aberration.
That would be the Hinode 5×21-A+ (ED version).
I was surprised to hear that they’d actually launched a pair of low-powered compact binoculars with ED glass for the following reasons.
Firstly, few people can tell the difference between their A5 (with normal glass) and A+ (with ED glass) because low-powered compact binoculars usually don’t have much achromatic aberration.
Secondly, low-powered compact binoculars are mainly used for sports or concerts, and the main buyers are low-end consumers.
Thirdly, it’s risky for a manufacturer to launch this configuration, not knowing if they can make a profit.
I compared the A5 (normal glass) with A+ (ED glass) thoroughly as soon as I got my pair.
Except for the color, their outward appearance is identical.
Looking at the scenery from my window, I couldn’t distinguish much difference.
This was a little disappointing, but of course, I had to compare them in a more challenging situation.
The moon was about 70% full that night, which helped me see the difference more clearly.
With the A5, I easily noticed a red and purple fringe on the edge of the moon. Also, I had difficulties focusing, which didn’t occur in the daytime.
Near the edge of the moon, I found the ‘Sinus Iridum,’ which is surrounded by high mountains. I tried to focus again and again to find a position where I could get a sharp image, but I couldn’t.
Next, I looked at the moon through the A+ pair.
Achromatic aberration could still be found, but it was dramatically reduced. It was not a colorful fringe anymore, just a very thin purple line.
I could very easily focus on the high mountains surrounding the Sinus Iridum crater.
I’ve seen this area of the moon many times not only with binoculars but also through telescopes, but I was amazed by how clearly I could see the ridgelines of the mountains with such low-powered compact binoculars.
“So, these are low-powered ED binoculars assembled in Japan”, I said to myself.
That was the moment I felt as happy with my new Hinode A+ as I had when I tried out the flagship models of Zeiss.
According to what Hinode Optics told me, unlike the A5, the A+ is carefully assembled in Japan, which makes the assembly very accurate.
Some of the most experienced workers are involved in the assembly.
In addition, the sides of the lenses and prisms where light doesn’t pass are painted in matte black very carefully to improve contrast. This requires great patience.
With normal binoculars, the singer would be surrounded by stray light, which prevents you from getting a high contrast image. The careful work of the matte black painting greatly reduces the annoying stray light.
I checked how much the black paint can reduce stray light by looking through the binoculars at an LED streetlight at night. I found that the 5×21-A+ has about one-third as much stray light as the 5×21-A5.
In the daytime, it’s difficult to tell the difference between these two models.
Looking through the A+ at a big tree with new leaves, I was very impressed by the depth of focus. I could focus on both the closest and furthest leaves at the same time.
The lens coatings on the A+ are as good as the ones on the A5. Combined with much less color fringing, the A+ gives you a much more exact and natural color.
The photos of Hinode 5×21-A+(plus)
These binoculars are for those who can tell the difference
I don’t think many people will be able to tell the difference between the A+ (ED) and the A5 (normal glass). Even an enthusiast like me can’t find many advantages of the ED lenses.
In certain situations, however, where the definition is put to the test, the A+ performs much better than the A5.
The price of the A+ is about $50 more than the A5. Different people will have different opinions about the value of the improved design.
I’m sure that novices would be perfectly happy with the A5. But, an enthusiast who wants to get a sharp image without achromatic aberration would think the A+ is a really good bargain.
I’m excited about the A+ because for the first time in a long time I could quickly and easily focus on a target.
Don’t miss this great opportunity!
However, I do have a concern about the A+: I wonder how long the A+ will be on the market. As I mentioned, the A+ is designed mainly for binocular enthusiasts, so if there is not enough interest to justify continued production, Hinode Optics could stop making them at any time.
Therefore, if you really want to get nice quality low-powered compact binoculars with ED glass, I suggest that you place an order as soon as possible.