Eyepieces have different AFOV, why not binoculars?

[Stonius (Markus)]

I decided to replace my old binoculars (by 'old', I mean I remember watching Kiss on-stage at Adelaide oval with them back in 1980 and we'd had them for a while even then!).


Anyway, they recently fell apart (I'm assuming those two events are not related, lol!) and I was in the market for a new pair. I figure maybe some things have improved since then, like optics, coatings and maybe my taste in music.



The two numbers habitually cited seem to be magnification and aperture, eg; 10x50.


Which is weird - much is made of the field of view of different EP's, but for Bino's it seems to be all about magnification and light grasp.


I was hoping to find something like a binocular version of an ethos or something, with lovely wide views, but it's almost like the EP's in all binoculars are some standard design and so the AFoV is just a function of the other two numbers.


Is this correct?


Cheers


Markus

[astro744]

The true field is sometimes stated in degrees but often feet at 1000 yards or metres at 1000m and you can calculate the angular true field using inv. Tan. To get apparent field multiply by magnification.

I have binoculars ranging from 45, 49, 60, 80.5 deg. apparent field. The latter being some old and very wide true field 7x35 I picked up recently. Apparent field is not used since in daytime use one can determine the distance to an object of known width by seeing how much field it takes up. The reverse also applies in that if you know an objects distance you can work out it’s width. In night time use knowing angular separation in degrees is all that really matters and you don’t really care if say a 6.5 deg field is at 7x, 8x or 10x magnification.

[anj026]

Generally wide angle binoculars will cost more. This is not just because of the more sophisticated eyepieces, it also due to requiring larger prisms to accommodate the wider light cone.

Nikon make a fantastic wide angle 10x50 with wide angle eyepieces and flattener lenses. These have a 9 degree field of view. It is very expensive (more than $8200 AUD) but is considered a landmark achievement in optics and very highly rated by binocular enthusiasts.
http://www.holgermerlitz.de/nikon_wx/nikon_wx.html

At a more common affordable level there are 10x50's such as Fujinon FMT SX which go for around $1200 AUD. Or the Chinese equivalents which are $600-700 AUD. These have a 6.5 degree field.
http://www.holgermerlitz.de/fuji_rover_10x50.html

Then around the $300 AUD mark there are the Nikon and Pentax 10x50's made in China. The Nikon has 6.5 degree field but not very sharp off axis. The Pentax has a sharp 5 degree field.
https://www.cloudynights.com/topic/7...n-ex-10x50-cf/

[Stonius (Markus)]

Originally Posted by anj026

Generally wide angle binoculars will cost more.[...]
Nikon make a fantastic wide angle 10x50 with wide angle eyepieces and flattener lenses. These have a 9 degree field of view. It is very expensive (more than $8200 AUD) but is considered a landmark achievement in optics and very highly rated by binocular enthusiasts.
http://www.holgermerlitz.de/nikon_wx/nikon_wx.html

Yikes!! Wow, at that price, they cost more than any telescope I own. I see Binoculars as an adjunct to the end goal of finding things with the telescope, not the other way round. In my head I was willing to spend up to $600, but I just ended up going for the old Saxon 20x80's for less than half that. I think they'll be fine, and the tripod mount will add a huge amount to what can be seen just by virtue of being stable.


I had a look at the comet with the old ones tonight. It's kind of nice that that will be one of the last things they get used for.


Markus

[Hoges (John)]

You often have to look at different retailers sites or the manufacturers sites to find apparent field of view / eye relief stats. They are usually available - particularly from the better known brands. Apart from specialist telescope/binocular shops, hunting/shooting retailers often have a good range of bino's that you can look through.

[Bobbyoutback]

I collect early Japanese extra wide angle binoculars ( 10deg & up ) because they don't make these now .

Most are in the 7x35 format , my all time favorite are a pair of Swift Sport king mark 1 ' the field of view is 630ft at 1000yds or 12 degrees !

I do have some modern wide angle binocular sets but the view can not compare to the 50+ year old super wide's .

Have Fun
Bobby

[miker]

Made in Japan. 8x40 9.5 degree. I purchased in 1966 for $22.00 (new currency).
Still going strong.

Michael.

Picture inverted for some reason.

[Bobbyoutback]

The old super wide angle binoculars were built for performance , today it seems all about cost .

If you see a nice 11
degree field of view offered - buy it if the price is reasonable !

Bobby

[anj026]

I have never seen much in the way of vintage binoculars available locally.

Some of the best new wide angle binoculars still available (under $1000) are the Kowa BD II 6.5x32 and the Nikon 8x30 EII.

[Bobbyoutback]

Originally Posted by anj026

I have never seen much in the way of vintage binoculars available locally.

Your correct Andy ' I buy them from the USA but postage is expensive & sometimes they are out of collimation

Earlier this year I bought a rare pair of Montgomery Ward 7x35 super wide angle 11.6 degree bins from the states that arrived out of collimation , unfortunately my efforts to fix them have come up short so they now live in a dark cupboard .