High power binoculars, the less well known meaning (1 Viewer)

[kimmik]

What is a high power binocular?

Most people define it as magnifying power. 15x is higher power than 10x.


The other definition is light gathering power -

10x56 has greater power than 10x42, fairly straight forward.

But also, 10x56 has greater power than 15x56, due to the greater true FOV.

 

[Maljunulo]

As far as I have ever read, light gathering “power” is determined solely by aperture. Can you cite something which shows otherwise?

Field of view has nothing to do with it.

Perhaps I misunderstood your post.

 

[wllmspd]

Exit pupil or some kind of calculation using the numbers to give some form of metric for low light/astro/other performance?

Peter

 

[William Lewis]

Hi Kimmik.

I think it usually refers to both high magnification and large objective size. For example the Nikon 18x70 if wp or fujinon 16x70 fmtr sx. For practical use (with a tripod mainly) they really need to go hand in hand or your going to be left with a pin prick of an exit pupil and a very dim view!

I'm at the sea side at the moment and have had the dubious pleasure of looking through a few of those heavy permanently mounted binoculars you often see at the end of piers round the English coast - the ones at the end of the pier in Hastings are free for a change! I'm not sure what there specification is but in general you can expect zero ipd adjustment, graffiti on the objectives, no diopter and a rusty "video" head with no lock off- they almost always have a high power to disappoint...

Will

 

[Patudo]

The other definition is light gathering power -

It is a less well known meaning because you are the only individual I have ever come across that uses "high power" binoculars in the context of light gathering!

 

[Maljunulo]

It is a less well known meaning because you are the only individual I have ever come across that uses "high power" binoculars in the context of light gathering!

Same here.

 

[CharleyBird]

Magnifying power
Light gathering capability

 

[kimmik]

It is a less well known meaning because you are the only individual I have ever come across that uses "high power" binoculars in the context of light gathering!

Thread '- The nominal luminous power of the binoculars:'

- The nominal luminous power of the binoculars:

As everyone will know, there is still no simple formula that describes the ability of binoculars to lighten civil twilight and part of nautical twilight. And therefore, that can indicate the luminous power of the instrument, or at least the nominal one. The twilight factor indicates the ability...

www.birdforum.net

 

[kimmik]

Handbook of optics, Bass 2009, reference manual for the optical society of America:



"The amount of flux which can be transmitted through a prism or other optical element depends on both its angular aperture and its cross-sectional area. The greater the amount of flux which can be transmitted, the better the throughput or light-gathering power (sometimes called
étendue or luminosity) of the system."

 

[Maljunulo]

Thread '- The nominal luminous power of the binoculars:'

- The nominal luminous power of the binoculars:

As everyone will know, there is still no simple formula that describes the ability of binoculars to lighten civil twilight and part of nautical twilight. And therefore, that can indicate the luminous power of the instrument, or at least the nominal one. The twilight factor indicates the ability...

www.birdforum.net

Having just skimmed that thread, I found it neither informative nor “enlightening“.

Maybe it’s me.

 

[Hermann]

Thread '- The nominal luminous power of the binoculars:'

- The nominal luminous power of the binoculars:

As everyone will know, there is still no simple formula that describes the ability of binoculars to lighten civil twilight and part of nautical twilight. And therefore, that can indicate the luminous power of the instrument, or at least the nominal one. The twilight factor indicates the ability...

www.birdforum.net

Oh well. One of those threads ....

Hermann