Keno 20-100x30 zoom binoculars (1 Viewer)

[yarrellii]

Yes, I know, common wisdom says that zoom binoculars are usually a poor choice (given that many are cheap devices with very poor quality, narrow FOV, etc., and there are few top brands selling quality top zoom binoculars, apparently for a reason). That’s why I was puzzled to find what appears a pretty shocking combination: a 20-100x zoom with 30 mm objectives, which ranges from a 1,5 to a 0,3 mm exit pupil.

What really puzzles me is that the binoculars in question are sold by Kenko, a brand that sells otherwise decent optics in low price ranges (they have a pretty complete range); sharing some models with other brands; for example they sell a clon of the much acclaimed Sightron Bluesky, and also a compact 6/8/10x30 not very different to the Opticron Savanna and its many siblings. In fact Kenko has created an entire page within their website to explain the details of these crazy zoom binoculars, somehow like they did believe it’s a viable product

You can check it here:
Kenko Global - SG-Z 20-100x30N FMC

Anyone has any experience with these? I have tried different models from different brands of the binoculars they seem to originate (the 6/8/10x30 sold by Kenko, Vixen, Opticron, related to the Kowa, Leupold, etc.), and they were very nice for the price. But why go the 20-100x way?

After trying scopes with 60 to 80 mm objectives and magnifications up to 60x, I’m really puzzled as to why Kenko would push the "good and trusty" 30 mm compact Porro to the 100x. I mean, for someone wanting magnification, maybe something like 10 - 30 x would have already been attractive, even 10-50 x, but why going up to 100 x, only because it sounds impressive in the ad? You do see ludicrous ads from impossible products in Aliexpress and the like, but very often they don't have a brand, or are sold by unknown brands, but reading Kenko’s website you get the impression that “they know what they’re doing”, and that this 20-100x30 will deliver… Puzzling.

 

[Binastro]

I have tried several reverse Porros with crazy magnifications.

The problem will be collimation.

Usually the crazy high magnification small binoculars are aligned, if at all, at the lowest magnification.
I estimated 2% were aligned at the high power.

Then there is the problem of focus in tandem and magnification in tandem.

The quality of the components probably doesn't allow the binocular to work properly.

Despite the protests here from birdwatchers, there is nothing wrong from my perspective with 0.3mm exit pupils.
Most skilled astronomers have used 65x per inch with high quality telescopes for fine detail on planets or planetary moons or double stars.

My Pentax 100mm f/12 refractor could easily take 300x in actual use and 400x for testing.

I haven't looked at the price of the above Kenco product.
There is also the problem of having skilled enough optics workers to have a go at aligning these.

My 25x-135x 80 binocular is well aligned at all powers, though it runs out of steam at 80x.
Higher than this is empty magnification.

I am not impressed with my 4 Kenco telescope adapters for lenses.
The eye relief is good but the field is small and all have internal dust.
I did get them at a low price though as a job lot.

Regards,
B

 

[Binastro]

I am not impressed with the Moon photo.
My Canon pocket camera does better with 40x zoom.

The fact that the Kenko 20x-100x 30 binocular is made in Japan is certainly an improvement on the Chinese offerings.
The 30mm versions usually go to 70x.

Even if an example of the Kenko binocular worked when new it is unlikely to stay working for long.

In the last post I called it Kenco, but I think that is coffee.

B.

 

[WJC]

Yes, I know, common wisdom says that zoom binoculars are usually a poor choice (given that many are cheap devices with very poor quality, narrow FOV, etc., and there are few top brands selling quality top zoom binoculars, apparently for a reason). That’s why I was puzzled to find what appears a pretty shocking combination: a 20-100x zoom with 30 mm objectives, which ranges from a 1,5 to a 0,3 mm exit pupil.

What really puzzles me is that the binoculars in question are sold by Kenko, a brand that sells otherwise decent optics in low price ranges (they have a pretty complete range); sharing some models with other brands; for example they sell a clon of the much acclaimed Sightron Bluesky, and also a compact 6/8/10x30 not very different to the Opticron Savanna and its many siblings. In fact Kenko has created an entire page within their website to explain the details of these crazy zoom binoculars, somehow like they did believe it’s a viable product

You can check it here:
Kenko Global - SG-Z 20-100x30N FMC

Anyone has any experience with these? I have tried different models from different brands of the binoculars they seem to originate (the 6/8/10x30 sold by Kenko, Vixen, Opticron, related to the Kowa, Leupold, etc.), and they were very nice for the price. But why go the 20-100x way?

After trying scopes with 60 to 80 mm objectives and magnifications up to 60x, I’m really puzzled as to why Kenko would push the "good and trusty" 30 mm compact Porro to the 100x. I mean, for someone wanting magnification, maybe something like 10 - 30 x would have already been attractive, even 10-50 x, but why going up to 100 x, only because it sounds impressive in the ad? You do see ludicrous ads from impossible products in Aliexpress and the like, but very often they don't have a brand, or are sold by unknown brands, but reading Kenko’s website you get the impression that “they know what they’re doing”, and that this 20-100x30 will deliver… Puzzling.

P.T. Barnum did not say, "There's a sucker born every minute." But someone working for him did. And he was right! Attached is a photo of a 7x50 labeled a 120x120. The dishonest know that the trusting or stupid LIKE big numbers!

 

[Binastro]

It is really fortunate that Sir William Herschel did not know that one should not trust big numbers.

With his home made 6.2 inch telescope he found an unusual looking star.

He used magnifications of 227x, 460x and 932x to examine the object and concluded that it was not a star.

It was the planet Uranus.

This planet had been observed frequently before, but nobody realised what it was.

B.