Binoculars and the eye?

[ollypenrice]

Obviously when you double the aperture by switching from a scope of aperture 'x' to bins of aperture 'x' you double the light grasp. But you don't, as even a casual glance will tell you, see this benefit. Similarly if you close one eye things don't appear significantly dimmer.

Does anyone know how to explain this rather disappointing situation?

Olly

[yesyes]

If I understand you correctly, then you only still have the same aperture per eye. Unfortunately the light collected by each eye is not cumulative.

[brianb]

IMHO there's no advantage in binoculars except comfort ... and comfort only applies when the eyepieces are not too far from the horizontal.

The obvious disadvantage of binoculars, in sizes over about 10x50, is that the weight is doubled for the same performance. This cancels out the comfort advantage.

[brantuk]

I figure you don't actually double the aperture or light grasp - per eye it's the same. The big benefit is seeing two slightly different pictures enabling you to comprehend depth and perspective - this is most marked in binoviewers that give a 3d spacewalk effect.

[yesyes]

this is most marked in binoviewers that give a 3d spacewalk effect.

Is that true? I thought, in the end, you see exactly the same with both eyes. The image is still coming through the same scope. Unless you're using a bino scope....

I never used bino viewers though...

[brantuk]

Oh - you just have to try bv's - it's an awesome way to view planets and stars. Totally different believe me

[yesyes]

I have no doubt about that. ;-)

But technically I don't think it's real 3D. It might be the brain making it appear so.

Still, binoviewers are on my "want list" ... ;-)

[Andrew*]

Using both eyes is the most natural and comfortable way to view - we have two: why not use two? Looking through a telescope one-eyed needs patience and skill, and usually causes more strain and discomfort than using both eyes. However, this only applies to well-adjusted binocular systems. If it's not set-up right, it causes just as much strain as the images are not aligned.

I'd say that using binoviewers in a telescope does not half the aperture (area, not diameter) due to light being shared by two eyepieces. You still get all the light - it is processed by the same brain, after all!

As for using 50mm binoculars rather than a 50mm monocular, I'd say you gain something, whether you call it an increase in comfort or a doubling of aperture...

To sum up, speaking personally, I've always seen the same or more with two eyes than one. I should add that I haven't done extensive tests on very faint objects with and without binoviewers, and would be very interested to know of experiences from folk who have.

Andrew

[Andrew*]

As for the 3D thing - you don't actually see 3D, it just seems like it.

[eddy]

It creates depth, thats why we have 2 eyes (being predators) to judge distance Thats what you get when you use a Bino viewer, a perception of depth, not a 3-D look, but more....i dont know how to word it, a more realistic look maybe? I guess using both eyes allows you to capture more detail and get a real feel about what your seeing in the sense of your not closing out 1 sensory input so making it feel a more natural and 'in the midst' of it feeling using 2 eyes, thusly producing a realistic, depth enabled enviroment.

Eddy

PS > Never used BV's just understand vision and the Brain

[yesyes]

OK, but for real depth perception (what I really meant when I said 3D) you need 2 completely independent light paths with a slightly different angle. The different angle is what allows your brain to perceive depth/distance.

With binoviewers you see exactly the same image with both eyes, i.e. you see the object you look at from the exact same angle with both eyes. So technically this should not allow you to perceive real depth. It can only be your brain adding that depth because it assumes that your eyes see things differently.

Anyway... way off topic now .. ;-)

Sorry, Olly..

[brianb]

With binoviewers you see exactly the same image with both eyes

at half the intensity (or a bit less) because the available light is spread across 2 "sensors". Binoviewers have never done anything for me, apart from losing faint objects, making the back end of the scope heavy & sometimes causing difficulty getting to focus.

Any sense of "depth" is an illusion, possibly caused by the axes of the eyepieces not being exactly parallel and/or the eyepieces being fractionally different in focal length.

Observing with both eyes open - and one covered - is just as comfortable and avoids the 50%+ light loss inherent in binoviewers.

[Jamie]

I am an avid fan of binocular viewing and the reasons for this are---

You get a more comfortable view than looking through a single lens + better eye relief.

Your brain is set up to receive information from 2 sources at the same time.

If the 2 sets of information are slightly different your brain will sort that out for you/merge the differences.

Binocular viewing enables you to see more detail and gives you a perception of depth.

Binocular viewing doesn't have the light loss/focusing issues associated with binoviewers

None of the above is guess work or what i THINK are reasons, these are my actual experience's of using binoculars of all shapes and sizes (even a pair i knocked up myself)

[yesyes]

Agreed. With binoculars (as opposed to binoviewers) you have 2 separate light paths. So you can see real depth.

[haitch]

I was under the impression you couldn't perceive depth of vision at (practical) infinity.

Surely it's the angle of view and comparitive spacing between the eyes of objects at different distances that gives depth of field? Even viewing the moon you wouldn't get that.

[Jamie]

When viewing the sun with my HA solar bins you get the perception of curvature on the outer limb of the solar disc. This has been viewed by many who have used these binoculars..

[Steve]

We are a million year-old species, we have evolved to use both eyes which is why we find it less comfortable using one and notice more when using two. Also, we 'see' with our 'minds eye', it isn't only physics which determines the view.

[Talitha]

IIRC it was EdZ (over at CN) who explained to me how/why the brain is able to 'process' more info when you use 2 eyes (binos) instead of one eye (telescope). There's apparently an actual improvement in magnitude detection but i can't recall exactly what the increase is. Regarding depth, my 22x100s definitely show the Dumbbell nebula in 3D. It seems to pop right out of the eyepieces.. absolutely mindblowing.

[Jamie]

I know that me and a couple of others have mentioned just how important the brain is in this equation. The thing that some folk might not know is that there is a bit of a learning curve involved in binocular viewing too.

You have to LET your brain do its job, that is not as easy as it sounds.

I have heard so many times "i can't see it" then all of a sudden you hear "wow" just as the brain factor kicks in and sorts the image out......

The brain has it's uses......

[GazOC]

I was under the impression you couldn't perceive depth of vision at (practical) infinity.

Surely it's the angle of view and comparitive spacing between the eyes of objects at different distances that gives depth of field? Even viewing the moon you wouldn't get that.

Thats my understanding. Looking at the moons of Saturn in my binoviewers I get the perception of 3D but I don't think its genuine. The spacing between the 2 sets of optics surely can't give genuine 3D at those distances?

[eddy]

You'd be suprised at how sensitive the brain is to images etc It really is an amazing piece of kit

[Jamie]

That's just it Gaz it's the "perception" of depth you get, this i think comes from your brain doing more work than you bargained for.

[GazOC]

That's just it Gaz it's the "perception" of depth you get, this i think comes from your brain doing more work than you bargained for.

It'd be an interesting test to get a set of binoviewers on Jupiter or Saturn and their moons and try and list the objects seen in order from nearest to farthest. It should tell how much if the view is perception and how much you are seeing genuinely in 3d.

[GazOC]

You'd be suprised at how sensitive the brain is to images etc It really is an amazing piece of kit

Its also very easy to fool though, theres plenty of 3d optical illusions kicking round the Internet.

[eddy]

Oh god yeah, the brain is FAR FAR FAR from perfect, it lies to you every single day! lol it'll always tell u the quickest answer before processing anything, a good educated guess as it were, so i guess the same rules true with Vision, what you think you see may not always be what you see....

Eddy