General Binocular Recommendations (1 Viewer)

[RandyBo]

This article from Cloudynights.com may help someone with their first binocular purchase. The latter part of the article is astronomy specific but, the first part is general information that any binocular user could use.

General Binocular Recommendations for Astronomy - Binoculars

What do you recommend for an all around first binocular General Binocular Recommendations for Astronomy by Ed Zarenski 3-3-07 What do you recommend for a first binocular? What can I expect to see? These are not uncommo...

www.cloudynights.com

 

[tenex]

Everything is multi-coated today, the issue now is fluoride glass.
Most glasses wearers now spurn 13mm (some even 15) ER.
There is no benefit to an exit pupil larger than your own?

I'm ever less sure that this sort of generalized guide is helpful to many people, especially for first-time purchase, because there's too much variety, not everyone cares about technical details, and some things are only learned through experience. It would be better just to suggest trying out a short curated list of models at three different price points.

 

[RandyBo]

Everything is multi-coated today, the issue now is fluoride glass.
Most glasses wearers now spurn 13mm (some even 15) ER.
There is no benefit to an exit pupil larger than your own?

I'm ever less sure that this sort of generalized guide is helpful to many people, especially for first-time purchase, because there's too much variety, not everyone cares about technical details, and some things are only learned through experience. It would be better just to suggest trying out a short curated list of models at three different price points.

I completely agree with all of your points. The article is somewhat dated and would likely only help someone who was starting at ground zero.
A basic understanding of terms like eye relief, field of view and exit pupil (and how they can effect binocular performance) couldn’t be a bad thing but, I also agree that “try before you buy” is always the best way to go.
The author’s point on exit pupil, I think, is worth considering. If a binocular has an exit pupil of 7mm and your pupils only open up to 5mm, can you get the maximum benefit from a 7x50 (which can mean a larger and heavier binocular). Would a beginner pick up on something like this in a showroom?

 

[Maljunulo]

Buy the best you can afford, and even just a bit more than that.

Consider a used version of a better binocular, rather than a new version of a not-so-good binocular.

Listen to the opinions of folks who have actually used the model in question, not the Spec-sheet Warriors.

Good luck.

(Ed Z’s little blurp is probably the best I have ever read on the subject)

 

[kimmik]

I completely agree with all of your points. The article is somewhat dated and would likely only help someone who was starting at ground zero.
A basic understanding of terms like eye relief, field of view and exit pupil (and how they can effect binocular performance) couldn’t be a bad thing but, I also agree that “try before you buy” is always the best way to go.
The author’s point on exit pupil, I think, is worth considering. If a binocular has an exit pupil of 7mm and your pupils only open up to 5mm, can you get the maximum benefit from a 7x50 (which can mean a larger and heavier binocular). Would a beginner pick up on something like this in a showroom?

Yes, bigger the ep, better the image, other qualities being equal, for many reasons, regardless of your eye pupil size.

Limiting yourself to small EP has to be one of the biggest myths ever in binoculars.

The downside is self apparent - heavier bigger bino.

 

[RandyBo]

Yes, bigger the ep, better the image, other qualities being equal, for many reasons, regardless of your eye pupil size.

Limiting yourself to small EP has to be one of the biggest myths ever in binoculars.

The downside is self apparent - heavier bigger bino.

Please forgive my ignorance and I certainly do not want to spread disinformation. I am still very much a rookie when it comes to optics. I thought this was more a scientific fact vs opinion (myth).
This quote is from Roger Vine’s review of a Nikon 7x50:

“Low light performance (twilight) is good for me with the Prostars, but only a little better than my binocs with 4mm exit pupils (12x50 SEs, 10x42 SEs and 8x32 Zeiss FLs). Why is this, given that a 7x50 should be much brighter?
The answer is that I am middle aged: older pupils don’t open as far and mine measure about 5-6mm in low light. So I am not a good judge of the Prostars in this respect; my 12 year old daughter says they are much brighter than binos with a 4mm exit pupil.”

 

[Mono]

An exit pupil larger than your eye's pupil is much more forgiving of placement. When one presents an optic to your eyes the light beam coming out of the eyepiece is rarely centred on your pupil, it takes a bit of wiggling to centre up. The larger the exit pupil the easier this is. If one is birding and taking one's bins up and down this can make quite a difference to one's experience of an optic.

 

[kimmik]

A couple of examples to illustrate the dilemma, in addition to the explanation from Mono:

Example - how familiar are you with photography and lenses, are you happy with that f4 kit lens, or do you want the f1.4, is the f1.4 only better for night time?

Example - do you prefer the comfort of a barstool, or a 3 person couch that technically is wasted space unless you want to lie down at night? If I take this further, how long can you enjoy sitting on a picket...

Example - can you fit a wide angle long eye relief eyepiece (ie large desirable eyepiece) in a 25mm binocular, or would it be better integrated into a larger objective body 42/50/56

 

[RandyBo]

@Mono and @kimmik
Thank You for your replys.
I can certainly see where a larger exit pupil would be less demanding on eye placement and, therefore create a more pleasant viewing experience….But, I do not see how this relates to pupil size and brightness (@kimmik, if your photography related comment explains this, I apologize).

So, for a very simple-minded man (myself), does a binocular with a 7mm EP have the same brightness for someone with a 5mm pupil size as it would for someone with a 7mm pupil size?

 

[Mono]

If you are using some 7x50 binoculars in the twilight when your pupils are wide open you will see a brighter image if you pupils open to 7mm then if they open to 5mm. This effect is much more relevant to astronomers than birders as under most birding conditions one's pupil will be much smaller. The benefit of larger exit pupils is more than just that extra brightness in twilight and full night-time conditions.

This is an interesting study, even up to 69 years old some people were recording 7mm pupils.

Dark-adapted pupil diameter as a function of age measured with the NeurOptics pupillometer - PubMed

The dark-adapted pupil diameter is an important clinical variable when planning refractive surgery. Surgeons can compare a patient's dark-adapted pupil diameter with the results of this population study to identify outlier measurements, which may be erroneous, and repeat testing prior to surgery.

pubmed.ncbi.nlm.nih.gov

 

[RandyBo]

If you are using some 7x50 binoculars in the twilight when your pupils are wide open you will see a brighter image if you pupils open to 7mm then if they open to 5mm. This effect is much more relevant to astronomers than birders as under most birding conditions one's pupil will be much smaller. The benefit of larger exit pupils is more than just that extra brightness in twilight and full night-time conditions.

This is an interesting study, even up to 69 years old some people were recording 7mm pupils.

Dark-adapted pupil diameter as a function of age measured with the NeurOptics pupillometer - PubMed

The dark-adapted pupil diameter is an important clinical variable when planning refractive surgery. Surgeons can compare a patient's dark-adapted pupil diameter with the results of this population study to identify outlier measurements, which may be erroneous, and repeat testing prior to surgery.

pubmed.ncbi.nlm.nih.gov

Thank You.
I will certainly check that link out.

 

[kimmik]

In theory same brightness. In practice, no one gets ipd and eye relief adjusted perfectly, and no one fixates only on image center to keep the pupils aligned. In this non perfect but actual use case, the 7mm will be brighter.

 

[Maljunulo]

@Mono and @kimmik
Thank You for your replys.
I can certainly see where a larger exit pupil would be less demanding on eye placement and, therefore create a more pleasant viewing experience….But, I do not see how this relates to pupil size and brightness (@kimmik, if your photography related comment explains this, I apologize).

So, for a very simple-minded man (myself), does a binocular with a 7mm EP have the same brightness for someone with a 5mm pupil size as it would for someone with a 7mm pupil size?

The retinas of person “A” (5mm pupils) will not receive as many photons as the retinas of person “B” (7mm pupils).

One might then assume that person “B” would see a brighter image, assuming equal photon-counting, signal processing, and image conversion performance in the two individual brains.

Also, the 7mm exit pupil only conveys an increased ease of eye placement if the observer’s pupils are smaller than 7mm at that moment.