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20x50 possible uses

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#1 gmazza

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Posted 28 December 2012 - 07:06 PM

I mean, what's the point of the 20x50 format, looks smaller exit pupils for astronomy use, too high magnification for terrestrial views handheld (please exclude from this topic discussion about image stabilized models)

Companies keep delivering this format to market so it should have a definite use.

The only I see is to watch nearby bird nests, tripod mounted, in daytime, due to the, relatively, short focusing distance for the magnification.

Any more ideas ?

#2 Jawaid I. Abbasi

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Posted 28 December 2012 - 07:33 PM

Firstly, if the binocular in high quality then you will see much better view for moon, Venus, Jupiter and Saturn. The double like Mister will see easily due to be smaller exit pupil and 20x magnification. As an example of Pentax 20x60 PCF WPII ; The views for m42, m45, planets and moon looks good though the FOV is quite small but the optics are high quality.

You still need a tripod in my opinion but many folks here using the binocular without tripod.

Keep in mind that an average person's pupil open 2mm to 3mm in day time so smaller exit pupil is not a deficiency in day time.

#3 Joad

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Posted 28 December 2012 - 08:03 PM

I was sucker-punched by a 20X50 binocular some years ago (only cost $25, so it could have been worse). We have to remember that most binocular buyers know nothing about exit pupils or really anything at all about how binoculars work. 20X50 just seems to be nice because it is a higher power than 7X50 (hence, all those ads for binoculars with powers over 100X!). What I didn't know then (but know now) is that the exit pupil is too small on a 20X50, and thus the view is too dim. I also didn't think at the time about how the higher magnification makes for much more difficult hand held viewing (this is obviated by image stabilized binoculars).

In short, a cheap 20X50 is designed for people who don't know much about binoculars. Mine went out of collimation all by itself (never dropped or roughly handled), and was thrown away years ago.

#4 BillC

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Posted 28 December 2012 - 08:05 PM

Meter readers use such instruments to read meters that must be read from a distance; it sure beats climbing every power pole in the county.

BillC

#5 gmazza

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Posted 28 December 2012 - 08:05 PM

Firstly, if the binocular in high quality ....


Nice, but is there a high quality model you could recommend for me in this format ?

Please, some model available to buy, avoid talking about collectible binoculars that I need to hang for months on auction sites to get.

As an example of Pentax 20x60 PCF WPII


The 60mm objective deliver more light and more image resolution for these magnifications, there are excellent choices in the 60mm objective and 20+ magnification

But, at 20x magnification, and 50mm objective, what is the possible niche ?

#6 BillC

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Posted 28 December 2012 - 09:05 PM

"But, at 20x magnification, and 50mm objective, what is the possible niche ?"

Sometimes, we filter information through OUR needs, OUR understanding and OUR wants, instead of thinking of the needs and wants of others. I just gave an example, based on sales I’ve made on just such instruments.

There are those out there who couldn’t care less about the night sky. As often as not, I hear people talk of “astrology” when they mean “astronomy.”

With its 2.5mm exit pupil, it wouldn’t be an instrument I would favor. However, for the purpose I described—and other similar needs—it works just fine.

Cheers,

BillC

#7 Man in a Tub

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Posted 28 December 2012 - 11:19 PM

Unusual binocular use

Note Kenny's reply.

:grin:

#8 ronharper

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Posted 29 December 2012 - 12:57 AM

Although such small exit pupils give a dim view that I consider "un binocular like", some people here think they're fine, and of course telescopes often operate with exit pupils as small as 1mm and nobody complains. So, it's just an aesthetic judgement, to say 2.5mm is too small.

But small exit pupils yield star images of an ultrafine pointlike quality. If the binocular is optically good and in good alignment, it would be excellent for bright double stars as close as 7 arcseconds or thereabouts.
Ron

#9 Jawaid I. Abbasi

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Posted 29 December 2012 - 03:38 AM

Firstly, if the binocular in high quality ....


Nice, but is there a high quality model you could recommend for me in this format ?

Please, some model available to buy, avoid talking about collectible binoculars that I need to hang for months on auction sites to get.

As an example of Pentax 20x60 PCF WPII


The 60mm objective deliver more light and more image resolution for these magnifications, there are excellent choices in the 60mm objective and 20+ magnification

But, at 20x magnification, and 50mm objective, what is the possible niche ?

That is why; I gave an example of Pentax which is very good in my opinion and if you are into the double then as Ron said that it will show you some double star nicely. I did not see in 20x50 much but Bushnell, zhumell and Nikon has it and I never had those so I can not say anything.

Another one is kowa 30x82 but I never had a chance to peek through. All I hear that it is the best instrument to keep it.

#10 Tony Flanders

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Posted 29 December 2012 - 07:10 AM

I mean, what's the point of the 20x50 format, looks smaller exit pupils for astronomy use, too high magnification for terrestrial views handheld (please exclude from this topic discussion about image stabilized models).


Takahashi made a 22x60 unit that was (and still is) very highly regarded for astronomical use. Almost identical specs to 20x50.

I asked the same question about that unit, and one happy owner pointed out that it's ideal for viewing the Moon. Especially near full phase, there are many subtle shadings on the Moon that respond very well to two-eyed viewing.

20x or 22x is still much too low for viewing planets, so scratch that application ...

However, there are numerous deep-sky targets -- almost all, in fact -- that fit nicely in a 2.5-degree field of view. Just to take one obvious example, the Pleiades would be great in 20x50 binoculars, much better than in (say) 10x70s.

They still seem fairly specialized to me, though. If I'm going to view at 2.5-mm exit pupils or smaller, I'd rather use a telescope.

#11 edwincjones

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Posted 29 December 2012 - 08:39 AM

as we have said many times-all binoculars are compromises

if we wanted standardization, we would all use 8x40s for birding ;
10x50s hand held, and 100mms for tripod mounting, for the night sky;
but as I accumulate more and more binoculars, I can realize the benefit of different makes and models

my least used is a miyauchi 22x60 due to small exit pupil, dim views,
but it is great for school outreach events looking at the moon and brighter DSOs

edj



#12 Andresin150

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Posted 29 December 2012 - 09:08 AM

If excellent quality then it should be a good high magnification (for the size) unit. Unfortunately, the few models that come to my mind in that specific configuration are on the medium to low quality side.
As an example of small exit pupils, my 2mm 40x80Ed Docters are among the best optics you can buy (I think are the best in their size). And I know good optics....

#13 Jon Isaacs

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Posted 29 December 2012 - 09:22 AM

They still seem fairly specialized to me, though. If I'm going to view at 2.5-mm exit pupils or smaller, I'd rather use a telescope.



I agree...

I think the question here is this:

To provide acceptable views, 20x binoculars need to be tripod mounted. If you are going to trouble of dealing with a tripod and all, why use 20x50s rather than something larger?

Jon

#14 Andresin150

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Posted 29 December 2012 - 09:26 AM

Portability. Thats why I dont carry around the 40x150's anymore, althoug is obvious that those "see" deeper...

#15 edwincjones

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Posted 29 December 2012 - 10:01 AM


I think the question here is this:

To provide acceptable views, 20x binoculars need to be tripod mounted. If you are going to trouble of dealing with a tripod and all, why use 20x50s rather than something larger?

Jon


to read a meter, or label on equiptment,
brief handheld, or supporting on car top or tree, would be easier

edj

#16 brentwood

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Posted 29 December 2012 - 10:59 AM

I have a cheapo, but yet well collimated 20x50 that I keep in the trunk to check out ships when we are down on the waterfront. We can also use them to keep our eye on the Americans who are to the north, east and south of us! :)

#17 planetmalc

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Posted 29 December 2012 - 12:38 PM

Companies keep delivering this format to market so it should have a definite use.

The only I see is to watch nearby bird nests, tripod mounted, in daytime, due to the, relatively, short focusing distance for the magnification.

Any more ideas ?


After astronomy, my binoculars are mainly used for viewing cityscapes, and I'd be doing just that with a 20 x 50 (tripod-mounted) if anyone made a good one, but they don't and they never have. There HAVE been some good glasses with mags around 20x - Pentax 20 x 60, Russian 20 x 60 and (my personal fave rave) the Miyauchi 22 x 60 - but they're a lot bigger than the conventional 20 x 50. It'd be the same if I lived on the coast and liked looking at shipping - a good 20 x 50 would be ideal.

I used to have a binocular catalogue by Denhill (a UK brand whose name derives from the address of the vendor's premises on DENmark HILL, in London), and their 20 x 50 was depicted being used for aircraft-watching, so maybe that's another specialist use.

#18 KennyJ

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Posted 30 December 2012 - 07:16 AM

< a good 20 x 50 would be ideal.>

To my knowledge,a "GOOD" 20x50 has yet to be made.

If one existed that had been manufactured to similar optical standards to the Takahashi 22x60 or Canon 18x50 it may well prove desirable as a specialized instrument,but every one I've seen has been of the very low budget variety.

Kenny

#19 planetmalc

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Posted 30 December 2012 - 08:13 AM

Gmazza: if you go back 6 pages of index to a thread called 'What do you think of this find' which was started on 22nd November, there's a possible contender on the last post of page 1. It's a 20 x 50 twin telescope (2 small spotting scopes, side-by-side with IP adjustment) that's smallish and lightish and has the advantage of 45-degree inclined eyepieces. I posted that its optical quality was 'OK but nothing special', but that was by today's stratospheric standards - in absolute terms it would have been as good as all but the very best around 40 years ago. It has a 2.5 degree FOV, but unfortunately it is not centre-focusing. They may still be available new.



#20 gmazza

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Posted 30 December 2012 - 07:28 PM

To provide acceptable views, 20x binoculars need to be tripod mounted. If you are going to trouble of dealing with a tripod and all, why use 20x50s rather than something larger?

Jon


Hi Jon,

Besides portability, as Andres pointed out, one additional reason is close focusing distance, for example, my 15x85 deliver amazing terrestrial images, but it's close focus is about 40m, and I have a subjective perception it not deliver it's best images this close. A 20x50 and 20x60 have close focusing distances at about 8 meters, so even tripod mounted it make sense in some settings.

Another reason is that users don't need acceptable, tripod quality, views for some of the discussed uses.

#21 Loren Toole

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Posted 30 December 2012 - 07:59 PM

About 6 years ago I was migrating slowly to higher bino powers, but hesitated to buy a 20x80 pair due to weight. So, I found a used pair of Japanese 20x50s to get oriented to using this magnification. I found the exit pupil was usable on brighter open clusters, the moon and especially the sun. I own a pair of mylar solar filters for these binos, it's one way to quickly preview the solar disk before setting up a scope.

I didn't find daytime views were difficult, it did take some effort to figure out the balance/stability issues. Actually this pair was a surplus military binocular so I am sure they served a useful purpose for daytime surveillance.

So, my experience seems to suggest a place for 20x50s... I've since migrated to 20x80s but occasionally pull out the 20x50s for certain objects.

#22 gmazza

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Posted 01 January 2013 - 01:42 PM

BillC

Meter readers use such instruments to read meters that must be read from a distance; it sure beats climbing every power pole in the county.

and

There are those out there who couldn’t care less about the night sky.


brentwood

check out ships when we are down on the waterfront.

and

keep our eye on the Americans who are to the north, east and south of us! :)


planetmalc

viewing cityscapes, and I'd be doing just that with a 20 x 50


Excellent, thank you very much for this feedback, I assume these real world uses are from people without the profile of reading binocular astro and birding forums, explained them the relative lack of topics on this format. In reality, running a search engine query with the term "what's the point of a 20x50" and the results will return this topic.

Loren Toole, thanks for talking about one astro related use.

Answering the "open agenda" secondary question, a binocular to watch, near home bird nests, mounted. I assume the quality side is a little step heavier on aperture, 60mm have a lot of quality models, most of them focus close enough.

A "hidden agenda" question is the fact I read somewhere else people recommending 20x50 as a great binocular to start on astronomy :jawdrop: :foreheadslap:
So I wasn't sure if I was the only one that think these aren't perfect binoculars to start on astronomy, now I'm at least assured I'm not the only one :p

#23 ngc 9999

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Posted 01 January 2013 - 03:21 PM

It is possible that those models don't work at full aperture and magnification, they may be something like 17x43.

#24 SMark

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Posted 02 January 2013 - 11:45 PM

I just noticed a Pentax 20x50 Selling on eBay.

I also noticed that it said "Made in China."






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