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

[Alexis Powell]

I have experience w/a lot of bins and other optical instruments and I can say for me that THE WIDER THE BETTER AS LONG AS THE VIEW IS SHARP AND FLAT. I have high-resolution (when corrected with eyeglasses) vision and am a very visually active person, constantly scanning my visual world, eyes darting this way and that. I like to see things sharply and to see details instantly as I look around my world in the course of everyday life. I make full use of the muscles that move my eyes around, so my eyeglasses are (modified) aviator style so that they impose no limits on the direction of my gaze. Moving the neck or body to see in different directions is important, but it is slow compared to pointing my eyes. For that reason, I also prefer glass eyeglasses lenses (or CR39 or Trivex if necessary) and abhor polycarbonate, which has too much chromatic aberration for sharp off-axis viewing. With polycarbonate eyeglasses lenses, I look around the field of view, catch sight of flying birds or other things that are hard to track or that appear and disappear from view quickly, but I can't see them clearly enough to identify them from a glimpse the way I can with better lens materials. Same sort of issues when driving a car. I want to be able to make maximal use of my darting and peripheral vision when crossing busy uncontrolled road intersections or when changing lanes in busy traffic, so aviator glasses with glass lenses are far superior to other options. To summarize, my goal, visually, at nearly all times in my life, is to have an instantaneously sharp view wherever my eyes are pointed. Consequently, when I put bins to my eyes, I want to be able to look at the world through the bins as if the bins weren't there and I were simply 8 (or 8.5 or 10) times closer to the world. Bins with a narrow field of view don't work--they make it restricted as if looking at the world through a tube, so I have to turn my head this way and that to see around. Bins with a super wide FOV but that are only sharp in the middle of the FOV are better, because more objects can be detected, but they are also very different from normal vision because I can't just look around the view and see things clearly. I want a bin to be like a transparent 8x picture window, not a window with a clear spot and a blurry surrounding area that requires me to move around on my side of the window to see different things on the other side of the window clearly by lining up the clear spot with my line of sight.

If you view the world the way I do, you will understand why a wide and flat field to the limits of one's peripheral vision is desirable. If you are the sort of person who looks at the world as if looking through a rifle scope, you won't understand where I am coming from at all. Different people are different. I also think that some older people have forgotten the joy and utility of darting one's eye's around. Unfortunately, progressive lens prescriptions do not allow for such viewing, so those who use them become trained to use their neck more actively to center objects in their view and they give up on the darting eyes. Side note: As my eyes have aged and lost accommodation ability I have been irritated at not being able to achieve sharp focus instantly when working (esp. indoors) at close to mid to far distances, back and forth, repeatedly. Consequently, I've been experimenting with bifocals and progressive lenses for several years. My current most-in-use eyeglasses set includes (1) single-vision glass prescription for distance viewing, (2) bifocal glass glasses with the close lens set low in the frame and with correction to allow sharp vision at about 12 inches, and (3) progressive Trivex glasses with the closest limit correction to allow sharp vision at 6 inches. All of these are set in aviator type frames. These days, I mostly use #2 when outdoors and birding/natural history exploring and I use #3 for indoors work and everyday life when the joy of quick sharp focus at different distances trumps the joy of a sharp off-axis view since a truly sharp off-axis view is no longer possible for my eyes at close distances except at a single specified distance with non-progressive glasses.

--AP

 

[Paultricounty]

I have experience w/a lot of bins and other optical instruments and I can say for me that THE WIDER THE BETTER AS LONG AS THE VIEW IS SHARP AND FLAT. I have high-resolution (when corrected with eyeglasses) vision and am a very visually active person, constantly scanning my visual world, eyes darting this way and that. I like to see things sharply and to see details instantly as I look around my world in the course of everyday life. I make full use of the muscles that move my eyes around, so my eyeglasses are (modified) aviator style so that they impose no limits on the direction of my gaze. Moving the neck or body to see in different directions is important, but it is slow compared to pointing my eyes. For that reason, I also prefer glass eyeglasses lenses (or CR39 or Trivex if necessary) and abhor polycarbonate, which has too much chromatic aberration for sharp off-axis viewing. With polycarbonate eyeglasses lenses, I look around the field of view, catch sight of flying birds or other things that are hard to track or that appear and disappear from view quickly, but I can't see them clearly enough to identify them from a glimpse the way I can with better lens materials. Same sort of issues when driving a car. I want to be able to make maximal use of my darting and peripheral vision when crossing busy uncontrolled road intersections or when changing lanes in busy traffic, so aviator glasses with glass lenses are far superior to other options. To summarize, my goal, visually, at nearly all times in my life, is to have an instantaneously sharp view wherever my eyes are pointed. Consequently, when I put bins to my eyes, I want to be able to look at the world through the bins as if the bins weren't there and I were simply 8 (or 8.5 or 10) times closer to the world. Bins with a narrow field of view don't work--they make it restricted as if looking at the world through a tube, so I have to turn my head this way and that to see around. Bins with a super wide FOV but that are only sharp in the middle of the FOV are better, because more objects can be detected, but they are also very different from normal vision because I can't just look around the view and see things clearly. I want a bin to be like a transparent 8x picture window, not a window with a clear spot and a blurry surrounding area that requires me to move around on my side of the window to see different things on the other side of the window clearly by lining up the clear spot with my line of sight.

If you view the world the way I do, you will understand why a wide and flat field to the limits of one's peripheral vision is desirable. If you are the sort of person who looks at the world as if looking through a rifle scope, you won't understand where I am coming from at all. Different people are different. I also think that some older people have forgotten the joy and utility of darting one's eye's around. Unfortunately, progressive lens prescriptions do not allow for such viewing, so those who use them become trained to use their neck more actively to center objects in their view and they give up on the darting eyes. Side note: As my eyes have aged and lost accommodation ability I have been irritated at not being able to achieve sharp focus instantly when working (esp. indoors) at close to mid to far distances, back and forth, repeatedly. Consequently, I've been experimenting with bifocals and progressive lenses for several years. My current most-in-use eyeglasses set includes (1) single-vision glass prescription for distance viewing, (2) bifocal glass glasses with the close lens set low in the frame and with correction to allow sharp vision at about 12 inches, and (3) progressive Trivex glasses with the closest limit correction to allow sharp vision at 6 inches. All of these are set in aviator type frames. These days, I mostly use #2 when outdoors and birding/natural history exploring and I use #3 for indoors work and everyday life when the joy of quick sharp focus at different distances trumps the joy of a sharp off-axis view since a truly sharp off-axis view is no longer possible for my eyes at close distances except at a single specified distance with non-progressive glasses.

--AP

I agree, different people are different 🤣.

 

[GrampaTom]

--AP

I was advised early on and think the advice is the same now, that because I was a heavy eye user, constantly looking here and there, demanded detail, and participated in activities that required in focus peripheral vision heavily, progressives were not the best idea. The lens shape of the progressive region was/is hourglass shaped, it was explained, and so things would be in and out of focus peripherally in unexpected and probably undesirable ways. So stick with conventional Bifocals. You seen this?

Like you my bifocals are set low, perhaps for a different reason than yours (maybe not). Im taller than many and with the conventional Optician location, the closeup lens top would often cut across people's chins I was looking at and talking to. As well like you I get more vertical vision with the distance lens above that way. I fully agree best sharpness across a nice flat field - (ahem that "effective FOV" thingy) is what I want. re your desire for widest FOV that supplies those, I suspect we need to look through and compare to see what we're talking about. As I recall for instance, I believe you love the Victory Pocket 825. So do I.

 

[Trinovid]

If you stay with the bino you have, train with it, learn its quirks, notice movement at the edge of the view, move your head so the thing that attracted you is now near the center of the field that is in focus... isnt that what we do? Its not about the bino. Its about what the bino does and how we learn to take advantage.

This is also spot on for everything we use in life, whether it's a brand/geometry of bicycle, fingerboard radius and strap hanging points for guitars and spatula styles for cooking. Learn the tool and you can make most all of them work for you.

I'm happy with the limited field of view in my ideally compact Leica's and they get better the more I use them.

 

[Thotmosis]

Since i use many different kind of binoculars daily about two years now my eyesight is really much better. I don't need glasses anymore, only for reading. So i'm telling my wife i need maybe even more binoculars in configurations i don't have yet, like an 8x56. We have to train this muscles to keep the eyes fit!

 

[Trinovid]

I also don't quite understand how it can be distraction when the field is too large and not "being able to take it all in". I mean, isn't that just how our eyes work with no bino attached?

That how my eyes seem to work and I'm glad you brought that point up!

 

[Brink]

That was my point Grandpa as well. First of all those super wide FOVs are barely noticeable. Nobody is birding at over three football fields, at least not with binoculars. If you are birding at 1000 whatever, then it’s a spotting scope with wide angle lens. This is a marketing thing, it’s about about the stat sheet to check boxes, where one has better performance numbers (that really don’t equate) to useful performance.

The difference between relatively modern binoculars with good FOVs (EL, FL, UVHD, MHG, conquest etc. etc.) are as useful as the newer kids on the block with very wide FOV, NL and SF. It’s like my car analogy, 500 hp is exceptional, start getting to six 700 hp and it’s not usable under normal conditions that you use a car for. It’s the same thing with wide field binoculars, in my opinion.

Think about some of these newer binoculars how much better the edges would be, if they just stopped them down a little bit. It would still be a very wide field.

Some birders use binoculars at distances > 1000 feet fairly often.

Also, the relative difference in FOV does not change with subject distance, so the NL Pure 10x42 will have a 40% bigger field than your 10x42 EL at any distance Tom.

 

[Alexis Powell]

I was advised early on and think the advice is the same now, that because I was a heavy eye user, constantly looking here and there, demanded detail, and participated in activities that required in focus peripheral vision heavily, progressives were not the best idea. The lens shape of the progressive region was/is hourglass shaped, it was explained, and so things would be in and out of focus peripherally in unexpected and probably undesirable ways. So stick with conventional Bifocals. You seen this?

Like you my bifocals are set low, perhaps for a different reason than yours (maybe not). Im taller than many and with the conventional Optician location, the closeup lens top would often cut across people's chins I was looking at and talking to. As well like you I get more vertical vision with the distance lens above that way. I fully agree best sharpness across a nice flat field - (ahem that "effective FOV" thingy) is what I want. re your desire for widest FOV that supplies those, I suspect we need to look through and compare to see what we're talking about. As I recall for instance, I believe you love the Victory Pocket 825. So do I.

Yes, I understand the advice that a "heavy eye user" might not find progressives satisfactory. It is as you note. I anticipated and received the same advice. But what I will say is that today's super-expensive progressives (e.g. Essilor Varilux X-series, as I have) are extraordinary technology that (like today's super-zoom camera lenses) seem to do the optically impossible, or at least are a major leap in capability and comfort over progressives of the past. If you have the money, I recommend giving them a try. I find them much more natural to use than I ever thought possible. No strange distortions. It is really very pleasurable to be able to instantly see things sharply from 6 inches to infinity, like having young eyes. Because I have such large frames, I can set the near correction very close and still have a gentle ramp to infinity. At infinity, they are very sharp off-axis, so distance vision is little compromised. Great for almost all everyday indoor uses.

I still prefer single vision or bifocals for birding, driving, or watching movies at the theater. With my large frames, the little close lens can be low but still quite large and easy to use when I want to look at small objects up close. Doesn't interfere with my view through bins most of the time.

Yes, I like the Zeiss 8x25 Victory because it is unmatched for that format, but it isn't truly flat or wide field so there is room for improvement. The Swarovski 8.5x42 EL SV is much closer to my ideal.

--AP

 

[GrampaTom]

Some birders use binoculars at distances > 1000 feet fairly often.

Also, the relative difference in FOV does not change with subject distance, so the NL Pure 10x42 will have a 40% bigger field than your 10x42 EL at any distance Tom.

OK, well. I'm skeptical of birders getting much information at 1000 yards or meters. Maybe someone on a boat coming into a harbor and wanting to discern the channel via green or red buoys. But birds? Maybe California Condors. Most will reach for their spotting scopes long before that.

Here's the point some of us are trying to make, expressed in numbers

@1000 yds NL Pure 1042 = 399'
@1000 yds EL 1042 = 336'
399-336=63/336=19% (rounded up), greater for NL

@100 yds NL Pure 1042 = 39.9'
@100 yds EL 1042 = 33.6
Thats 6.3', (divide that by 2 as you get half on each side)

@50 yds NL Pure 1042 = 19.95'
@50 yds EL 1042 = 16.8'
A whopping 3.15'

 

[Brink]

OK, well. I'm skeptical of birders getting much information at 1000 yards or meters. Maybe someone on a boat coming into a harbor and wanting to discern the channel via green or red buoys. But birds? Maybe California Condors. Most will reach for their spotting scopes long before that.

Here's the point some of us are trying to make, expressed in numbers

@1000 yds NL Pure 1042 = 399'
@1000 yds EL 1042 = 336'
399-336=63/336=19% (rounded up), greater for NL

@100 yds NL Pure 1042 = 39.9'
@100 yds EL 1042 = 33.6
Thats 6.3', (divide that by 2 as you get half on each side)

@50 yds NL Pure 1042 = 19.95'
@50 yds EL 1042 = 16.8'
A whopping 3.15'

California condors yes, hawk watching in general is often done at these distances. The late Jerry Liguori published a good (and quite popular) book about it.

The difference in FOV size changes with the square of field diameter, so the difference is actually closer to 40% (rounded down).

 

[Paultricounty]

Some birders use binoculars at distances > 1000 feet fairly often.

Also, the relative difference in FOV does not change with subject distance, so the NL Pure 10x42 will have a 40% bigger field than your 10x42 EL at any distance Tom.

Hi Brink

I was referring to a 1000 yards , over three football fields. Read Grandpa post #49, that about says it all. There might be applications at 1000 yards for 8 and 10 powered binoculars, but birding is very low on that list. As grandpa numbers indicate a distance of 50 to 100 yards you really just don’t notice it that much. I’ve experimented with this, handing very Widefield binoculars to people and then letting them compare something with substantially less FOV and they can barely tell the difference at relatively short distances. But everybody’s mileage may vary on how they like to use their equipment.

 

[Paultricounty]

OK, well. I'm skeptical of birders getting much information at 1000 yards or meters. Maybe someone on a boat coming into a harbor and wanting to discern the channel via green or red buoys. But birds? Maybe California Condors. Most will reach for their spotting scopes long before that.

Here's the point some of us are trying to make, expressed in numbers

@1000 yds NL Pure 1042 = 399'
@1000 yds EL 1042 = 336'
399-336=63/336=19% (rounded up), greater for NL

@100 yds NL Pure 1042 = 39.9'
@100 yds EL 1042 = 33.6
Thats 6.3', (divide that by 2 as you get half on each side)

@50 yds NL Pure 1042 = 19.95'
@50 yds EL 1042 = 16.8'
A whopping 3.15'

Perfect, that’s exactly what I was trying to relay. Thank you 🙏🏼

 

[GrampaTom]

The difference in FOV size changes with the square of field diameter, so the difference is actually closer to 40% (rounded down).

Oh, Ok the square area vs linear thing, got it. While I am in agreement, as folks who've read my prior stuff and seen my chart, (which includes SA) will know, I like SAFOV. But my take on it is it's another way of expressing FOV albeit one that probably should be taken along with linear, but does not stand in lieu of it. Two pieces of information are better than one as we struggle to describe what we see. I also think its one of those paper stats, that kind of overstates things. I don't know about you, but my brain can't take in all at once, all the information in the whole square area of the view in my EL1042. I believe what we're looking at, at any point in time is not the whole 360 degree circle, but a region of it, where our attention is focused. Movement on the periphery of the view catches your eye/brain, you shift your eyes there, simultaneously you move the bino to a more centered view and focus on that object. The square area obviously helps that, no doubt. I suggest the 40% value though, (and I put those on my chart) overstates the thing a bit. Actually just to be clear its Pi x radius squared, not diameter.

Either way, I stand by my point most birders are working at way less than 1000 yards and bino makers overstate FOV, using that distance for mostly marketing reasons, (at least if birders are the target market). Get much beyond a couple hundred yards and its spotting scope time.

 

[Brink]

Please explain that?

If the field of view is a flat circle (a fair approximation), it’s area is pi*r^2

 

[GrampaTom]

If the field of view is a flat circle (a fair approximation), it’s area is pi*r^2

See 53, sorry

 

[Maljunulo]

A have trouble understanding why some struggle so to grasp angular field expressed in degrees.

Distance is then irrelevant.

 

[GrampaTom]

A have trouble understanding why some struggle so to grasp angular field expressed in degrees.

Distance is then irrelevant.

We've had this conversation before. Youre welcome to your beliefs and opinions. You will remember others, like most notably Lee felt otherwise. Its all kinda BS, academic, as far as I'm concerned. We need to get out and use the things. These differences among the best binos we discuss, are not worth the ink... One bourbon in.

 

[Brink]

Diameter squared and radius squared are in direct proportion to each other and since you were using diameter I stuck with that for simplicity. This method does not overstate the difference, it is just very common for people to understate the difference.

It is true that the eye doesn’t examine the whole field at once, our eyes can only really see small details at a small central point on the retina- this is why your eye has to move to read this text, even on a tiny cellphone. Our eyes do use the rest of our vision to pick up shapes or movement to key in on though, and this is where a large FOV is really useful. Maybe some people don’t even realize the benefit they are getting from a larger FOV, or maybe the benefit is exaggerated for those of us who really try and get everything they can out of the instrument. In any case, it isn’t a marketing ploy. I say as long as the view is pleasant/useful, the wider the better.

 

[Steve C]

...

What if we cut through the smoke and mirrors? Divide the published linear FOV at 1000 whatevers by 10. After all with an 8X or 10X as a practical matter, 100 whatevers, (or less), is about where the birding information is actually useful. Then keep in mind you get half of that number on either side of the view. The differences, of the best new and improved aint huge. But the bino company convinces us this is a thing. Why? So they can sell more units.
...

I am a bit surprised somebody has not pointed this out. For example if a binocular has a liner FOV of 8*, each barrel is 8*. You don,t get 4* from each side. You get 8* from each side, just like we get 1x from our left eye and 1x from the right eye. Called binocular vision. This is dead simple to check for yourself.

I asked a couple of friends who were once optics dealers what most people looked for in a binocular. They said the most common wish was for one that would let them see a long ways off. I see that asked a lot at a couple of local dealers too. The next most common thing was wanting a binocular with big objective lenses so that they can get a bigger fov. 1,000 yards or meters is a "long ways off". More is better seems an integral part of human nature. More magnification, more fov.

Yeah there is a LOT of smoke and mirrors put out by the marketing folks. It's their job to make us think that buying their stuff was our idea. I agree there is such a thing as too much fov, just as there can be too little. That is a journey everyone need to take themselves. I also agree that just going out and using your binoculars and quit sweating the minutae is beneficial. However everybody is different.

 

[Ted Y.]

The monocular Leica Movid 8x20 has a Field of View of 110 m @ 1000 m.
The binocular Leica Ultravid 8x20 has a Field of View of 113.2 m @ 1000 m.

No binocular has the FOV the double of the FOV of the monocular: 110m x2 = 220m, meaning 220m @ 1000 m. Right?
For a binocular, the FOV of the left telescope has an intersection zone with the FOV of the right telescope.