What are your priorities in binoculars? (2 Viewers)

[tenex]

Amazing how many customers go for ease of use. Many are using binoculars for the 1st time. So how they
balance in the hands and how easily they can adjust them set them to suit their eyes, regards avoiding blacking
and correct eye relief is top of the list.
Also in many cases they will put a better set to one side because they cant get on with them despite my efforts
to help.

What's amusing is that such considerations never appear in any promotional material (except for eye relief). Viewing comfort comes to seem more a happy accident than a design feature. But I agree with Edwin above that this is not just a beginner thing; even today, a bin that isn't straightforwardly comfortable won't seem "better" to me. (This is why I don't care about the legendary qualities of Habichts.) My own list:

Viewing comfort (good eyebox, adequate depth eyecups -- not necessarily large EP)
60°+ AFOV
Excellent central sharpness with gentle falloff
Minimal aberrations, none ugly even at edge
Reasonably natural color/contrast (slight variation is fine; few today actually fail this test)
Not overly glare-prone
Solid quality feel, smooth focusing (not too slow; ~6ft/2m preferred)

(To elaborate for the OP, smeary coma/astigmatism near the field edge is a deal breaker for me, while modest field curvature or CA is not.)

 

[Dennis Mau]

From my observations, here are the possible tradeoffs that occur with each desired criteria, which one could look for and strike a balance. Thanks Dennis for the list:

1. Large AFOV (The bigger the better)
Eye relief, spherical aberration of exit pupil, hue shift in spectral extremes (reds and blues), weight and size

2. Flat field with tack sharp edges (The sharper the better)
globe effect, wavy distortion, blur at 70% field

3. On-axis sharpness
off axis sharpness

4. Good ergonomics and ease of use with no blackouts (Eye cups are long enough for ER)
shorter eye relief usually less blackouts, but maybe not glasses friendly

6. Brightness with high transmission
colour inaccuracy in spectral extremes (hue shift or dullness in reds and blues)

7. Low glare
tighter baffles, more vignette, less global brightness/throughput

8. True colors (No green, yellow or red tints)
neutral white balance can be tricked, causing colour inaccuracy (like fluorescent lighting, bright but less pleasing colours)

9. Low CA
maybe higher other aberrations, best to check for all of them.

10. Repairability, warranty, reputation and resale
cost

11. Country of origin and I prefer MIA, MIG, or MIJ (No MIC)
papilio and some other interesting binos are MIC

13. It must say Swarovski on it
all swaros feel similar, lacks variety if restricting yourself to one brand. Different brands have different strengths and personality.

I thank Kimmik for his posts. I am replying to his responses to my original post.

1. Large AFOV (The bigger the better)
Eye relief, spherical aberration of exit pupil, hue shift in spectral extremes (reds and blues), weight and size

The Swarovski NL has a huge FOV, no spherical aberration of exit pupil, no hue shift in the spectral extremes, and both the NL 32 mm and 42 mm are not overly heavy or big compared to the competition like a Leica Noctivid 8x42 that doesn't have nearly as big of a FOV.

Swarovski NL Pure 10x42 - binoculars review - AllBinos.com

The best binocular tests on the net. The comprehensive database of binoculars with their parameters and users opinions. Interesting articles and comparisons.

www.allbinos.com

2. Flat field with tack sharp edges (The sharper the better)
globe effect, wavy distortion, blur at 70% field

The Swarovski NL has very little globe effect, no wavy distortion and no blur at 70% field. It is one of the most distortion free binoculars made, and Allbinos found almost nothing wrong with it. One reason it is the number one binocular on their list.

Swarovski NL Pure 10x42 - binoculars review - AllBinos.com

The best binocular tests on the net. The comprehensive database of binoculars with their parameters and users opinions. Interesting articles and comparisons.

www.allbinos.com

3. On-axis sharpness
off axis sharpness

The Swarovski NL is probably one of the sharpest binocular there is off axis. With a perfect 10 on distortion and a 10 on blurring at the edge of the field on Allbinos.

Swarovski NL Pure 10x42 - binoculars review - AllBinos.com

The best binocular tests on the net. The comprehensive database of binoculars with their parameters and users opinions. Interesting articles and comparisons.

www.allbinos.com

4. Good ergonomics and ease of use with no blackouts (Eye cups are long enough for ER)
shorter eye relief, usually fewer blackouts, but maybe not glasses friendly

You're plain incorrect here. What determines blackouts is eye cup length, matching the ER of the binocular and how it interacts with the depth of your eye sockets. The NL series of binoculars has over six adjustments to get this adjustment as accurate as possible to avoid blackouts.



6. Brightness with high transmission
Color inaccuracy in spectral extremes (hue shift or dullness in reds and blues)

Brightness and high transmission has nothing to do with color inaccuracy in spectral extremes. The Swarovski NL has very high transmission but very accurate colors. The Zeiss HT and Swarovski Habicht are two other binoculars that have very high transmission but very accurate colors because of their very flat transmission curve.



7. Low glare
tighter baffles, more vignette, less global brightness/throughput

Proper baffling does not necessarily reduce transmission or brightness/throughput or vignetting. A Swarovski Habicht 7x42 and Zeiss HT 8x54 have very little glare and excellent baffling, but yet they have some of the highest transmission of any binoculars.



8. True colors (No green, yellow or red tints)
neutral white balance can be tricked, causing color inaccuracy (like fluorescent lighting, bright but less pleasing colors)

The NL has an excellent whiteness of image, but it still doesn't have any off colors or tints in the image. You don't need green and red tints for color accuracy. The Zeiss SFL is a good example. It has superb true colors, but no green tint like the FL.



9. Low CA
maybe higher other aberrations, best to check for all of them.

Just because a binocular has low CA doesn't mean it will have more aberrations in other areas. The aberrations are independent of each other.



10. Repairability, warranty, reputation and resale
cost

Sure, to get all these things, you have to pay more for the binocular. The manufacturer has to charge you more to build a binocular well enough that it can be repaired, and a good warranty is going to drive the price of the binocular up also, but isn't it worth it in the long run. Having these things builds the reputation of the manufacturer and also increases the resale of the binocular.



11. Country of origin and I prefer MIA, MIG, or MIJ (No MIC)
papilio and some other interesting binos are MIC

They may be interesting, but I have found the consistency and build quality on most MIC binoculars to be fair to poor. I avoid the frustration of dealing with these problems by not buying MIC. You get what you pay for in general.



13. It must say Swarovski on it
All swaros feel similar, lacks variety if restricting yourself to one brand. Different brands have different strengths and personality.

I agree, different brands have different strengths and personality. It is personal preference which brand you like because of their strengths. I have tried almost every major brand, and I have decided my main priorities when buying a binocular are a big FOV with a flat field and sharp edges. I have found Swarovski's to have some of the biggest FOV's with the flattest fields and sharpest edges of any binoculars, and that is what I prefer. I am not saying they are best for everybody, just for me.

 

[Harrier22]

always been a 8x42 fan for 30+ years

for me the biggest factors are

handling and how they feel in the hand
easy to use focus knob
weight and feel, i like a solid feeling binocular
sharpness
field of view
low light performance

and the strap! but this is the only thing i can change......my meostars came with no strap (ebay buy) tried to get a meopta strap but no luck, so got a black rapid bino strap good but too stretchy but always liked to distinct look of the kahles / waldkauz strap and cover, so after a few emails back and forth to austria it arrived last week. im hppy with them View attachment 1492397

The strap is beautiful and the binoculars look positively cozy!

 

[Ratal]

Do I get a feeling of deep satisfaction when looking at the bird and other wildlife / nature about me? Is the binocular a joy to use?

If yes? Keeper.

If no? Move it on.

Opticron Aurora 8x42 is a keeper for me.

 

[has530]

Skeleton bino 6x25, for the super wide 11.5° FoV, very solid construction and minimalist design.

Does this happen to be one of the ones made by Asahi Optical (pentax)? Judging from your post we have similar priorities and one of my favorite newer (to me) binos is a "Bushnell Broadfield" 6x25 11* that now lives in the center consul of my car. Excellent depth of field thanks to the 6x magnification means rarely do I need to refocus and the 11* field of view makes them perfect for a quick grab and find your target pair.

1. (with the power to end the list here): usability, ease of use, comfort, whatever you want to call it. The fact that you forget you are using them: be it for perfect eyecups, perfect focus wheel, perfect armour. A pet peeve of mine are narrow eyecups, which have ruined many an otherwise excellent bino for me.

I am the same, this ruined the 8x32 meostars for me (until I came across the UV eyecup codification here on the forum, now they are my "all purpose" bino) and may make me give up on my 8x20 UV and made me pass on the habichts. On the other hand I have a wide nose and deep set eyes so too large of eyecups are also a problem for me as I can't get them comfortably to my eyes, especially without intermediate stops. This made me give up on the Conquests, Sig zulu7 and zulu9, and almost the vortex vipers.

2. Flat field with tack sharp edges (The sharper the better)

What is about this that you love so much? Do you frequently fill your whole massive field of view of your NL's and want to observe details at each edge at the same time? Is it just that you have started looking at edges and can't unsee softening at the edge? Is it just you are enamored with the technology and enjoy it purely for the sake of having the best?

No ugly binos, aesthetic design must be pleasing or at least acceptable to me

I agree but this is also highly subjective. Would you mind sharing some you consider especially pleasing and especially ugly?

And nowadays I also want a stabilizer ...

I also have been grabbing my stabilized pairs more and more. This is mostly because it is the time of year for waterfowl and shorebirds which are frequently at a great distance so I either grab my Canon 15x50 IS for the extra reach or the 8x20 IS for steady one handed scanning while holding my spotter in the other.

7. Low glare
tighter baffles, more vignette, less global brightness/throughput

Proper baffling does not necessarily reduce transmission or brightness/throughput or vignetting. A Swarovski Habicht 7x42 and Zeiss HT 8x54 have very little glare and excellent baffling, but yet they have some of the highest transmission of any binoculars.

The problem arises when the baffling intrudes on the light path. Then you do not get a fully illuminated exit pupil and as a result vignetting.

9. Low CA
maybe higher other aberrations, best to check for all of them.

Just because a binocular has low CA doesn't mean it will have more aberrations in other areas. The aberrations are independent of each other.

I would contend that neither of these are accurate. My background comes from more electron optics, microscopy, and lasers/fiber optics but I will do my best to give a brief explination of my reasoning. Low CA is generally not corrected at the expense of other abberations, but most easily corrected at the expense of a compact size. See for example binoculars with exemplary correction of CA; Zeiss Victory SF, Bushnell Legend M, Kowa Genesis (which also benefits from a pure flourite element in an apochromatic triplit objective I believe), many porros... these are all above average in dimensions and specifically have objectves with a slower focal ratio. On the other hand some models I have found to have above average CA are the Leica Ultravid line, Nikon Monarch 7/HG, vortex razor...all nice and compact optics. Having a slower objective also generally reduces other aberrations such as spherical aberration. Additionally comatic and astigmatic aberrations are intimately related and often jointly corrected (along with field curvature...likely a reason your field flattened NL's are largely absent of these aberrations). This resource somewhat touches on some of this from the perspective of microscopy.

 

[mfunnell]

Low CA is generally not corrected at the expense of other abberations, but most easily corrected at the expense of a compact size.

Which explains much of my one-time problem, now (expensively) fixed. Until I set on my 8x32 FLs, I found plenty of 8x3x bins I thought were fine optically but were too big (for me, and my intended uses). I also found plenty of right-size 8x3x bins which didn’t work for me on the optics front. TBF, this was’t just CA - I found other problems too. (Sometimes the failure was as simple as insufficient ER, for me.)

…Mike

 

[Binocollector]

Does this happen to be one of the ones made by Asahi Optical (pentax)? .

No, it's a Seiwa Kogaku J-B93. According to the "miniaturebinos" website one of the largest makers.

 

[has530]

TBF, this was’t just CA - I found other problems too. (Sometimes the failure was as simple as insufficient ER, for me.)

That would make sense because although there are many other factors that go into eye relief (namely eye lens diameter, and field of view), eye relief is generally proportional to eyepiece focal length. Because magnification is objective focal length divided by eyepiece focal length, a longer objective focal length (and thus longer binocular body) requires a longer eyepiece focal length in order to achieve the same magnification, which therefore generally has more eye relief.

 

[A2GG]

I agree but this is also highly subjective. Would you mind sharing some you consider especially pleasing and especially ugly?

some attractive examples IMO would be Swaro EL SV and original CL, Leica Ultravid and Classic Trinovid. Noctivid and Trinovid HD are also nice.
Zeiss SF 32 is mostly attractive but not quite on the level as the above mentioned.

Ugly IMO would be original Meostar with the little bumps on it as a prime example.
Zeiss FL and Swaro NL are mostly ugly IMO

 

[Harrier22]

Do I get a feeling of deep satisfaction when looking at the bird and other wildlife / nature about me? Is the binocular a joy to use?

If yes? Keeper.

If no? Move it on.

Opticron Aurora 8x42 is a keeper for me.

Well said!
Cheers

 

[Dennis Mau]

Does this happen to be one of the ones made by Asahi Optical (pentax)? Judging from your post we have similar priorities and one of my favorite newer (to me) binos is a "Bushnell Broadfield" 6x25 11* that now lives in the center consul of my car. Excellent depth of field thanks to the 6x magnification means rarely do I need to refocus and the 11* field of view makes them perfect for a quick grab and find your target pair.


I am the same, this ruined the 8x32 meostars for me (until I came across the UV eyecup codification here on the forum, now they are my "all purpose" bino) and may make me give up on my 8x20 UV and made me pass on the habichts. On the other hand I have a wide nose and deep set eyes so too large of eyecups are also a problem for me as I can't get them comfortably to my eyes, especially without intermediate stops. This made me give up on the Conquests, Sig zulu7 and zulu9, and almost the vortex vipers.


What is about this that you love so much? Do you frequently fill your whole massive field of view of your NL's and want to observe details at each edge at the same time? Is it just that you have started looking at edges and can't unsee softening at the edge? Is it just you are enamored with the technology and enjoy it purely for the sake of having the best?


I agree but this is also highly subjective. Would you mind sharing some you consider especially pleasing and especially ugly?


I also have been grabbing my stabilized pairs more and more. This is mostly because it is the time of year for waterfowl and shorebirds which are frequently at a great distance so I either grab my Canon 15x50 IS for the extra reach or the 8x20 IS for steady one handed scanning while holding my spotter in the other.


The problem arises when the baffling intrudes on the light path. Then you do not get a fully illuminated exit pupil and as a result vignetting.


I would contend that neither of these are accurate. My background comes from more electron optics, microscopy, and lasers/fiber optics but I will do my best to give a brief explination of my reasoning. Low CA is generally not corrected at the expense of other abberations, but most easily corrected at the expense of a compact size. See for example binoculars with exemplary correction of CA; Zeiss Victory SF, Bushnell Legend M, Kowa Genesis (which also benefits from a pure flourite element in an apochromatic triplit objective I believe), many porros... these are all above average in dimensions and specifically have objectves with a slower focal ratio. On the other hand some models I have found to have above average CA are the Leica Ultravid line, Nikon Monarch 7/HG, vortex razor...all nice and compact optics. Having a slower objective also generally reduces other aberrations such as spherical aberration. Additionally comatic and astigmatic aberrations are intimately related and often jointly corrected (along with field curvature...likely a reason your field flattened NL's are largely absent of these aberrations). This resource somewhat touches on some of this from the perspective of microscopy.

Do you prefer the 55-inch big flat screen TV's we have now, or do you prefer the old 25 inch curved CRT TV's we used to have? When I go from a smaller FOV to a larger FOV it feels like looking down a tunnel. I notice soft edges and I can see the edges of the FOV in my binocular just like you can see the edges of your TV, and I don't care for it when they are fuzzy. Would you want your TV to have fuzzy edges with just the center sharp? I don't think so. With a bigger FOV I can see more at once, and I catch birds and wildlife that I might miss in a binocular with a smaller FOV. That is why Lee enjoys his SF 8x32 in Scotland because of the big open country he is observing and the bigger FOV lets you see more of it at one time without scanning all the time. It is personal preference, but I don't think Swarovski and Zeiss would have made the NL and SF their new alpha binoculars if a lot of people didn't like a big FOV. I sold my Zeiss SFL 8x40 because my NL 8x32 had a much bigger FOV and sharper edges, which I prefer.

There was a long thread on baffling and light transmission on Bird Forum and I have linked it below, but it was concluded, and many experts agreed, that if baffling is done correctly it has no or very little effect on transmission. There are many binoculars that have excellent baffling with very little glare and still have superb light transmission, like the Habicht 7x42 and Zeiss HT.

I agree that focal length plays a big part in CA and SA control, but it is just one part of binocular design, and you have to consider the total binocular design in determining how much CA it will have. With modern ED and fluorite glass types, a lot of CA can be eliminated without having a long focal length. Look at how short the newer Apochromatic Triplet telescopes are, and they have almost no CA. The Zeiss FL 8x32 is another good example. It has a short focal length, but because of its high content of fluorite glass, it has some of the best CA control of any binocular. A lot of the other aberrations like comatic, astigmatic and field curvature are corrected at the eyepiece by adding extra elements like field flatteners. A big reason why the SF and NL are longer and bigger than a Leica UVHD binocular, which has a less corrected FOV.

Baffles and Light Transmission

On the thread comparing NL 8x42 with SF 8x42 dorubird posted the following and I am hoping one of our optics experts (Henry, are you there?) will comment on this: "Maybe EDG 8x42 it is such a rare bird. But due to the very aggressive baffling diaphragm I think it loses light transmission. No...

www.birdforum.net

 

[kimmik]

transmission is not same as light throughput.

look through a straw and it is 100% transmission.

look through WTC glass and it is maybe 30% transmission.

so agree, baffle doesn't affect "transmission" as defined by manufacturers. it never did.

 

[Binocollector]

Do you prefer the 55-inch big flat screen TV's we have now, or do you prefer the old 25 inch curved CRT TV's we used to have? When I go from a smaller FOV to a larger FOV it feels like looking down a tunnel. I notice soft edges and I can see the edges of the FOV in my binocular just like you can see the edges of your TV, and I don't care for it when they are fuzzy. Would you want your TV to have fuzzy edges with just the center sharp?

That TV-comparison makes no sense. The actually sharp FoV of your own eyes is 2° and sharpness declines very fast towards the periphery.
A TV is fixed in place and you move your eyes to see the whole image (and that does not even take into consideration that nowadays often cameras with very shallow depth of focus are used so often 90° of the image on the TV is out of focus anyway).
In a wide angle bino, you cannot even notice with peripheral vision (and I mean it is physically impossible) that the edge is fuzzy, so you need to be moving your eyes within the FoV and looking straight at it because your eyes only see 2° sharp (of the FoV of your own eyes, not sure how it translates to the FoV of the bino) and in focus.
So instead of rolling your eyes around within the FoV, how about moving the bino?
I mean, I like a flat field as much as the next bloke but still, it's impossible to "see" the fuzzy edges when keeping your bino pointed at what you want to observe.
Flat field makes more sense when using a tripod or for astronomy.
It's nice to have of course. But it's not really necessary because you cannot even see it, especially when flat field is combined with a large FoV. And binos with smaller FoV will have better edge sharpness anyway.
When noticing movement in peripheral vision (which is just as easy with a normal bino compared to a flat field bino -- especially when considering that the movement at the edge would have to be in the same focal plane to even be in focus) you can simply move the bino so that whatever you want to see is in the middle of the FoV.
So bottom line is -- yes, a super well corrected FoV is nice (and expensive) but it will basically make not much difference in daily use.
That doesn't mean that the NL is not the technically the best (one of the best maybe, together with the Zeiss SF) EWA bino out there but really for any use case apart from stationary use, a large FoV with a flat field is "nice to have" at best.
And we haven't even mentioned the fact that what we are looking at is not a flat wall in a certain distance but there might well be a bit of shrubbery closer to you which would then be in focus in a wide FoV with field curvature.
For long range observation on a tripod -- yes, it would absolutely be more useful than for other use cases.

 

[Dennis Mau]

That TV-comparison makes no sense. The actually sharp FoV of your own eyes is 2° and sharpness declines very fast towards the periphery.
A TV is fixed in place and you move your eyes to see the whole image (and that does not even take into consideration that nowadays often cameras with very shallow depth of focus are used so often 90° of the image on the TV is out of focus anyway).
In a wide angle bino, you cannot even notice with peripheral vision (and I mean it is physically impossible) that the edge is fuzzy, so you need to be moving your eyes within the FoV and looking straight at it because your eyes only see 2° sharp (of the FoV of your own eyes, not sure how it translates to the FoV of the bino) and in focus.
So instead of rolling your eyes around within the FoV, how about moving the bino?
I mean, I like a flat field as much as the next bloke but still, it's impossible to "see" the fuzzy edges when keeping your bino pointed at what you want to observe.
Flat field makes more sense when using a tripod or for astronomy.
It's nice to have of course. But it's not really necessary because you cannot even see it, especially when flat field is combined with a large FoV. And binos with smaller FoV will have better edge sharpness anyway.
When noticing movement in peripheral vision (which is just as easy with a normal bino compared to a flat field bino -- especially when considering that the movement at the edge would have to be in the same focal plane to even be in focus) you can simply move the bino so that whatever you want to see is in the middle of the FoV.
So bottom line is -- yes, a super well corrected FoV is nice (and expensive) but it will basically make not much difference in daily use.
That doesn't mean that the NL is not the technically the best (one of the best maybe, together with the Zeiss SF) EWA bino out there but really for any use case apart from stationary use, a large FoV with a flat field is "nice to have" at best.
And we haven't even mentioned the fact that what we are looking at is not a flat wall in a certain distance but there might well be a bit of shrubbery closer to you which would then be in focus in a wide FoV with field curvature.
For long range observation on a tripod -- yes, it would absolutely be more useful than for other use cases.

Quote from Dalat:
"It's not the first time this issue is raised here, and what I've learned from the many discussions is: those that have binoculars with edges not so sharp, think sharp edges are not important; and those that have binoculars with sharp edges think it is important."

Quote from Lee:
"I am a target-centering observer like you, and only stumbled into the realization of how important sharp edges can be when whale watching on Skye this July. With the whales only being visible for a very few seconds, it was necessary to decide very quickly whether that small shadow out at the periphery of view was the beginning of a whale-back surfacing or not. A wide FOV and better edge sharpness would have been appreciated. And since looking through Zeiss's new SF I have come to realize how this extra dimension to the view can be important, and, yes, I have to apologize to all of those EL SV owners who already knew this and whose opinion on the matter I have not taken seriously enough."

Quote from Torview:
"I didn't use to think it's important, however I’ve used my SE as my primary Birding bin for 18 months now and really notice the lack of edge sharpness in bins without it. I think nearly all SV owners will tell you it's hard to give up on once accustomed."


When I go from a binocular with sharp edges and a huge FOV like the NL to a binocular with less sharp edges, I notice it right away. Even though I may not be looking at the edges all the time. I can see them in my peripheral vision. I also find the sharp edges useful, as Lee says to identify a bird that comes into my FOV at the edge. I think some people rationalize that they don't need sharp edges because sharp edges are expensive, It takes a complex expensive Nagler type eyepiece as in the NL to deliver a fully corrected FOV that is sharp to the edge. And we all know Swarovski's are not cheap. I easily notice when a binocular starts softening towards the edge and I find it distracting, especially if it severe. A fully corrected big FOV with sharp edges is more advantageous than you might think because you can scan a bigger area and really see what is there quicker and faster than with a smaller FOV that is even made smaller by soft edges. The only reason I can see to accept a smaller FOV with soft edges, IMO, is cost.

 

[has530]

Quote from Dalat:
"It's not the first time this issue is raised here, and what I've learned from the many discussions is: those that have binoculars with edges not so sharp, think sharp edges are not important; and those that have binoculars with sharp edges think it is important."

I don't think we have the same interpretation of this quote. Do you think they are saying that once you try E2E sharpness you realize how important it is? Because my interpretation would be that those who have convinced themselves to fork out the extra money for flat field binoculars have convinced themselves of the advantage while others have decided it is not worth paying for.

I do not dispute the advantages of a wide field of view when scanning for a moving target, but as mentioned above by @Binocollector, your eye only has a sharp FOV of about 2° (unmagnified, not to be confused with binocular TFOV, this would mean only the central 2° of the total AFOV will have full visual acuity). This means that you can never use the full sharp FOV of flat field binoculars all at once. While it can be nice to let your eye wander and observe to the edge of the field of view without moving the optic (especially while mounted... the reason I own a flat field astronomical telescope eyepiece for my spotting scope), in reality you can see the same thing by just slightly changing where the binocular is pointing rather than where your eyeball is pointing (this has the added advantage of keeping your eye centered in the exit pupil mitigating problems that come with pupil decentering). Is it nice to "have the best" and be able to let your eye wander and not notice any softening? Sure. But do you gain much from having tack sharp edges vs good enough to see something is there edges? I would contend the answer is no...in the case of handheld binoculars.

There are many applications where flat fields are advantageous. For starters, telescopes and mounted optics in general. I do not have a tracking mount for my telescope so having a wide perfectly corrected field of view is advantageous in that you can watch your target progress through the field of view without aberrations at the edge (the same holds true for spotting scopes with moving targets). For any imaging application (photography, microscopy...) where the sensor reads the full image simultaneously, then it is advantageous as any edge aberrations will be recorded. It is for these applications the technology was developed and where it really shines.

 

[Dennis Mau]

I don't think we have the same interpretation of this quote. Do you think they are saying that once you try E2E sharpness you realize how important it is? Because my interpretation would be that those who have convinced themselves to fork out the extra money for flat field binoculars have convinced themselves of the advantage while others have decided it is not worth paying for.

I do not dispute the advantages of a wide field of view when scanning for a moving target, but as mentioned above by @Binocollector, your eye only has a sharp FOV of about 2° (unmagnified, not to be confused with binocular TFOV, this would mean only the central 2° of the total AFOV will have full visual acuity). This means that you can never use the full sharp FOV of flat field binoculars all at once. While it can be nice to let your eye wander and observe to the edge of the field of view without moving the optic (especially while mounted... the reason I own a flat field astronomical telescope eyepiece for my spotting scope), in reality you can see the same thing by just slightly changing where the binocular is pointing rather than where your eyeball is pointing (this has the added advantage of keeping your eye centered in the exit pupil mitigating problems that come with pupil decentering). Is it nice to "have the best" and be able to let your eye wander and not notice any softening? Sure. But do you gain much from having tack sharp edges vs good enough to see something is there edges? I would contend the answer is no...in the case of handheld binoculars.

There are many applications where flat fields are advantageous. For starters, telescopes and mounted optics in general. I do not have a tracking mount for my telescope so having a wide perfectly corrected field of view is advantageous in that you can watch your target progress through the field of view without aberrations at the edge (the same holds true for spotting scopes with moving targets). For any imaging application (photography, microscopy...) where the sensor reads the full image simultaneously, then it is advantageous as any edge aberrations will be recorded. It is for these applications the technology was developed and where it really shines.

No, I think once you get used to a flat field binocular with sharp edges you notice the difference when you try a binocular with softer edges even if you are not looking directly at the edges. As Torview says, once you become used to a binocular with sharp edges, it is hard to give it up. You may not be able to use the full flat field of the FOV at one time, but you can move your eyes quickly to the edge when you pick up movement, and a lot of times you can make an ID that way. That is what Lee is saying in his quote about spotting whales. As soon as the whale was back surfacing, if he had had a binocular with sharp edges he could have identified it, but with soft edges the whale would have been submerged again before he could see it clearly.

A lot of times with a binocular with sharper edges you can ID a bird as soon as it comes into the FOV which you could not with a binocular with fuzzy edges. When you say in reality you can see the same thing by just slightly changing where the binocular is pointing rather than where your eyeball is pointing (this has the added advantage of keeping your eye centered in the exit pupil, mitigating problems that come with pupil recentering) is true, but it takes LONGER to do that and by the time you get the bird recentered it could be gone!

Why do you think Swarovski and Zeiss developed huge FOV's, flat fields and sharp edges for their SF and NL binoculars? It is because there is a huge advantage to using them when birding and hunting. They didn't do it just for the heck of it!

 

[Hermann]

I do not dispute the advantages of a wide field of view when scanning for a moving target, but as mentioned above by @Binocollector, your eye only has a sharp FOV of about 2° (unmagnified, not to be confused with binocular TFOV, this would mean only the central 2° of the total AFOV will have full visual acuity). This means that you can never use the full sharp FOV of flat field binoculars all at once. While it can be nice to let your eye wander and observe to the edge of the field of view without moving the optic (especially while mounted... the reason I own a flat field astronomical telescope eyepiece for my spotting scope), in reality you can see the same thing by just slightly changing where the binocular is pointing rather than where your eyeball is pointing (this has the added advantage of keeping your eye centered in the exit pupil mitigating problems that come with pupil decentering). Is it nice to "have the best" and be able to let your eye wander and not notice any softening? Sure. But do you gain much from having tack sharp edges vs good enough to see something is there edges? I would contend the answer is no...in the case of handheld binoculars.

Strongly seconded.

Hermann

 

[dries1]

"No, I think what he is saying is if you can't afford to buy a flat field binocular like the Swarovski NL or Zeiss SF, you rationalize it by saying you can't see the edges when in reality you can".

 

[Binocollector]

Quote from Dalat:
"It's not the first time this issue is raised here, and what I've learned from the many discussions is: those that have binoculars with edges not so sharp, think sharp edges are not important; and those that have binoculars with sharp edges think it is important."

Yeah, not sure how that quote even applies as I currently own 7 flat field binos.

 

[Binocollector]

When you say in reality you can see the same thing by just slightly changing where the binocular is pointing rather than where your eyeball is pointing (this has the added advantage of keeping your eye centered in the exit pupil, mitigating problems that come with pupil recentering) is true, but it takes LONGER to do that and by the time you get the bird recentered it could be gone!

You must be really slow in moving your binoculars.
And like I already mentioned - this line of thought implies that everything you observe is in the same distance.
Another thought - even the best modern flat field binos have still not reached the FoV of vintage EWA binos. So in one of those I might even see another bird even further out from the center.
And yet another thought - with eyes that accommodate quite well, the edge of the FoV of a Kowa 8x32 with 8.8° is pretty damn sharp. You won't identify all that more birds with an NL.
And once more for the record - I don't doubt they are the best but for any practical applications it makes no difference.