FOV - beyond what value is too much? (1 Viewer)

[Paultricounty]

ugh... those SF's are looking mighty tempting. For small EP, I assume eye relief would be poor. I wonder how the 8x32SF's do with eyeglasses?

Absolutely no problems with the SF wearing sunglasses, and I can take in the whole field. Another interesting thing that occurred today, while playing around with eye positions and moving my eye around with and without the sunglasses, was the blue ring I described earlier. With the cups all the way extended if you can get the cups close and tight around the eye socket the blue was to noticeable. Pull it slightly away and it can be seen.

 

[Maljunulo]

Close, but no cigar …… “globe sphere“ is redundant.

 

[Steve C]

I'm wondering, do we create these issues being discussed here today? If we think we're buying binoculars as distinct from say, going birding, and we're trying really hard to assess this bino vs that one, so we work the view real hard trying to see this visual issue or that, are we setting up the reactions a couple of you are describing here?

Just a thought.

I think there is a lot to this point. I have often wondered about it and have come to the conclusion we probably do indeed create some of our own problems. There is the phenomenon of the self fulfilling prophecy.

 

[Steve C]

We need to stop calling it rolling ball, because that sounds dizzying. Why don’t we call it globe affect🤣 that way when people look in their binoculous they’ll see globeffect and not get nauseous 😜

It is aptly named as it is. When I had to give up on the Swarovski SV EL series, it was due to the way rolling ball affected me. It did make me nauseous and dizzy. Much like Binocollectors point in post 113. I never did expect to see it in the firat place from my first view through the SV, but was soon disabused of that notion. I have no doubt there was something somewhat unique between my DNA based optical system and the mechanical optical system iof the SV, and I harbor no illusions that my experience is in anyway applicable to anyone else. I have often thought that if I was GOD, I'd give everyone my rolling ball experience just for a few hours. That would be enough of an experience to settle the issue.

 

[Troubador]

It is aptly named as it is. When I had to give up on the Swarovski SV EL series, it was due to the way rolling ball affected me. It did make me nauseous and dizzy. Much like Binocollectors point in post 113. I never did expect to see it in the firat place from my first view through the SV, but was soon disabused of that notion. I have no doubt there was something somewhat unique between my DNA based optical system and the mechanical optical system iof the SV, and I harbor no illusions that my experience is in anyway applicable to anyone else. I have often thought that if I was GOD, I'd give everyone my rolling ball experience just for a few hours. That would be enough of an experience to settle the issue.

I have only seen this phenomenon on one occasion and then only briefly. I was using a scope to view ducks and thought I had finished but a small flock of ducks arrived nearby and I couldn't resist quickly panning the scope around to get 'one last look'. At this point the scope was defocused and as I panned it the resulting rolling ball nearly made me throw up (only slight exageration). It was a shock because I hadn't noticed any RB when previously panning but those panning events were done at much slower rates and with the scope focused. Point is when I saw the RB it was not pleasant. At all. I haven't done extensive experimenting looking through binoculars with a reputation for RB but when I have panned with them I haven't seen RB, but as Steve hints at, my DNA-based optical system is probably unique to me and is no guide to what others may experience.

Lee

 

[mwhogue]

If the field gets too wide it is going to look bad; I wouldn't want to bird through a fisheye lens, for example. Maybe 65 degrees is the reasonable limit to how wide a field can be and still look good to a typical user. I haven't looked through any old-school wide field binoculars, so I am not sure why they've gone away

Brink, I would be happy to be corrected but I believe these binos had very little eye relief.

Lee

Brink,Lee,

That's my guess. I recently got a very nice old 7x35 porro with a 12.5 field. But with only 10 mm ER the view and FOV is fairly compromised with my close fitting spectacles. So I prefer using them without glasses but the ER is so tight I have my wife trim my eyelashes to avoid smudging the lenses. So these types are not as convenient or versatile generally.

Mike

 

[mwhogue]

Hi Tom
(edit)

It is simply the case that I find bigger fields of view of great practical value in the field and I note that if one bino has an X% bigger area of view at 1,000 metres than another bino model. it also has an X% advantage at every viewing distance.

Lee

I agree with Lee. Extreme example - looking at faster flying butterflies and dragonflies the much wider FOV of the Kowa 6.5x32 (CF 1.1 m) versus Papillio 6.5 (CF 0.5 M) is a big practical advantage for me even at 1.1 m. Both excellent bins though IMO.

Mike

 

[Ted Y.]

Well... yes, we do. I get SAFOV is proportional. So too is linear FOV. The point? Writing SAFOV is 40% larger is another of those potentially impressive numbers. We both have agreed, I believe though, pure SAFOV overstates things a bit as we cant take in the whole area at once anyway. We did right? Why not publish the number, the calculated product for SAFOV at 100 or 50? Isn't that better information?

It can be more relevant for some users, agreed.

It is also important to have a unique way to present the FOV, for easy comparison.

It seems it is, globally, x @ 1000m (or yrds).

Two keywords: “is” and “globally”.

This way to present the FOV is almost impossible to change. Like for keyboards, a laptop and a 100 years old manual typewriter have the same keyboard layout, even if it is not optimal.

 

[Troubador]

I agree with Lee. Extreme example - looking at faster flying butterflies and dragonflies the much wider FOV of the Kowa 6.5x32 (CF 1.1 m) versus Papillio 6.5 (CF 0.5 M) is a big practical advantage for me even at 1.1 m. Both excellent bins though IMO.

Mike

Exactly, Mike.

Lee

 

[William Lewis]

We're used to a field of view of roughly 135 degrees when we haven't got binoculars in the way. For context an 8x bin gets you up 125m from a target 1000m away - if you were actually standing that 125m away with no bins your field of view would be 1080m...

I'm happy as long as I can get a bird on the wing within the field stop first go and have found that I can with around 115m at 1000m as my last few pairs of bins have had around that true field of view so I'm used to pointing them.

That's all providing you primarily bird with you naked eye first then train in on movement or likely areas of interest - for scanning large areas looking for that movement a wider field of view would definitely be preferable as Lee says.

Well corrected large fields of view are quite expensive though!

 

[Ted Y.]

We're used to a field of view of roughly 135 degrees when we haven't got binoculars in the way. For context an 8x bin gets you up 125m from a target 1000m away - if you were actually standing that 125m away with no bins your field of view would be 1080m...

I'm happy as long as I can get a bird on the wing within the field stop first go and have found that I can with around 115m at 1000m as my last few pairs of bins have had around that true field of view so I'm used to pointing them.

That's all providing you primarily bird with you naked eye first then train in on movement or likely areas of interest - for scanning large areas looking for that movement a wider field of view would definitely be preferable as Lee says.

Well corrected large fields of view are quite expensive though!

As I understand, the central view (foveal high-acuity part) is "only" 6 deg, the sepecific value for a person depending of some factors. This is during the day light.
I imagine a binocular having a FOV of 9 deg needs to be well corrected for the 6 deg of central view and less corrected for the rest.
Can someone to have a central view of 10 deg? I do not know. If "yes", the 9 deg of the binocular are not enough.

 

[Brink]

As I understand, the central view (foveal high-acuity part) is "only" 6 deg, the sepecific value for a person depending of some factors. This is during the day light.
I imagine a binocular having a FOV of 9 deg needs to be well corrected for the 6 deg of central view and less corrected for the rest.
Can someone to have a central view of 10 deg? I do not know. If "yes", the 9 deg of the binocular are not enough.

The angular subtense of the image you see through the binocular is much more than 6 degrees, more like 60 degrees for a modestly-sized field. So when looking through a binocular your foveal high-acuity part is only covering about 1% of the FOV.

 

[Troubador]

The angular subtense of the image you see through the binocular is much more than 6 degrees, more like 60 degrees for a modestly-sized field. So when looking through a binocular your foveal high-acuity part is only covering about 1% of the FOV.

But at least you can move your eyes around and direct this high-acuity field to different areas of the field of view.

Lee

 

[Brink]

But at least you can move your eyes around and direct this high-acuity field to different areas of the field of view.

Lee

Indeed. It has been mentioned a number of times that wide fields aren't very useful because our eyes can't "take it all in" or some such. The ad absurdum extension of this is that our eyes really can't take in more than a fraction of a degree true FOV for detail examination. Our eyes make excellent use of a much greater field of view than just what is focused on the fovea, this is why many of us prefer wider fields.

 

[Alexis Powell]

But at least you can move your eyes around and direct this high-acuity field to different areas of the field of view.

Lee

Exactly. Ideally, a bin will be well corrected across the whole FOV so one can look through it like an open window, darting one's eyes around the view just like when looking at the world without bins. Otherwise, one must keep one's eyes locked down the center axis and pan the bin to see around clearly, which is very unnatural and inefficient.

--AP

 

[Troubador]

Exactly. Ideally, a bin will be well corrected across the whole FOV so one can look through it like an open window, darting one's eyes around the view just like when looking at the world without bins. Otherwise, one must keep one's eyes locked down the center axis and pan the bin to see around clearly, which is very unnatural and inefficient.

--AP

Thanks Alexis, and full use of your peripheral vision means that you can quickly become aware of objects closer to the edge of the fov and re-direct your vision to take a more detailed look at it. The big point here is that these techniques enable you to make use of the full field of view even if your eyes cannot accept the entire field at any single moment.

Lee

 

[Tringa45]

But at least you can move your eyes around and direct this high-acuity field to different areas of the field of view.

Lee

Not really, Lee, unless your binocular has really large exit pupils.
The human eye has a diameter of 24 mm and I would guess the pupil is at a radius of about 11 mm, so a 30° rotation would result in a lateral movement of nearly 6 mm and vignette the exit pupil.
At one inland water observing location, where closer access was impossible I used to set up my 10x42 on a tripod next to my scope just to get a comfortable wider field view of what flew in before having a closer look with the scope. Anything on the left required moving my head to the right to compensate for the rotation of my eyes to the left.
Every year the German nature conservancy organisation, NABU, calls on the public to count the garden birds seen within an hour. An unusual situation perhaps, but I was able to direct my 8x56 SLC at any movement seen in the foliage and roam around the FoV searching for the bird. Couldn't do that with a compact!

John

 

[Binastro]

Post #131.

The fovea covers 1 degree.
The macula 5 degrees.

A 9 degree binocular has magnification, say 8 times.
The AFOV is about 70 degrees.
This is the coverage on the retina.

From my observations I take the sharpest part of my eyes to be 2 degrees across.

The Sun is 0.5 degrees across.
Directly staring at the Sun harms the most sensitive part of the eye.

With an 8x binocular staring at the Sun damages both eyes at the central 4 degrees.

The US soldiers in Vietnam took care to damage only the central part of the shooting eye with an exposure of 30 seconds. Without optical aid.
They were shipped home although doctors clearly saw this was deliberate self harm.

The eyes get information from 200 degrees sideways, considerably less up and down.

I have frequently seem meteors and artificial satellites with 70 to 75 degree AFOV binoculars that I would have missed with narrow angle binoculars.

B.

 

[StephenHampshire]

Exactly. Ideally, a bin will be well corrected across the whole FOV so one can look through it like an open window, darting one's eyes around the view just like when looking at the world without bins. Otherwise, one must keep one's eyes locked down the center axis and pan the bin to see around clearly, which is very unnatural and inefficient.

--AP

Interesting, I find darting my eyes around the field of view of a binocular quite disconcerting, If I see something of interest on the periphery I do move the whole bino, which I find much more comfortable! Might be because I wear varifocal specs, or possibly I'm just a little odd...Still would take a larger FoV over a smaller one given the choice

 

[Richard D]

Interesting, I find darting my eyes around the field of view of a binocular quite disconcerting, If I see something of interest on the periphery I do move the whole bino, which I find much more comfortable! Might be because I wear varifocal specs, or possibly I'm just a little odd...Still would take a larger FoV over a smaller one given the choice

No I don't think you're odd. If I scan the landscape for a bird without binoculars I move my head, so I do the same with binoculars, in my experience it's the most natural and efficient way. I don't recall seeing many people standing around with head still and eyes moving side to side