[denco@comcast.n]

Why can't Nikon or Swarovski or Zeiss make an alpha binocular with a 600 foot FOV and totally sharp edges? The old Nikon porros had a huge FOV but the edges were usually lacking in sharpness. They have telescope eyepieces like the Nagler now with a huge FOV and they keep getting larger so why not binoculars. What optical principal limits the FOV. I want a Nikon EDG like view with a 600 foot FOV!

[FrankD]

My limited understanding from what I have read would lead me to believe that prism size is the culprit. I am sure you have seen many of the lclassic porros that do offer huge fields of view. Almost all of them have huge prism housings to, well, house the large prisms. The larger prisms are needed to avoid any type of incursion into the light path.

How far off am I on this one Henry?

Since roof prism models have narrower bodies it would be difficult to create one with an extra wide field of view that did not have extremely fat barrels to accomodate the larger prisms needed.

[denco@comcast.n]

Originally Posted by FrankD

My limited understanding from what I have read would lead me to believe that prism size is the culprit. I am sure you have seen many of the lclassic porros that do offer huge fields of view. Almost all of them have huge prism housings to, well, house the large prisms. The larger prisms are needed to avoid any type of incursion into the light path.

How far off am I on this one Henry?

Since roof prism models have narrower bodies it would be difficult to create one with an extra wide field of view that did not have extremely fat barrels to accomodate the larger prisms needed.

So if you didn't need a prism like in a telescope eyepiece you can have huge FOV like the Naglers?

[SEOW]

Holger Merlitz on the subject:

http://www.holgermerlitz.de/wide/wideangle.html

[black crow]

Originally Posted by denco@comcast.n

Why can't Nikon or Swarovski or Zeiss make an alpha binocular with a 600 foot FOV and totally sharp edges? The old Nikon porros had a huge FOV but the edges were usually lacking in sharpness. They have telescope eyepieces like the Nagler now with a huge FOV and they keep getting larger so why not binoculars. What optical principal limits the FOV. I want a Nikon EDG like view with a 600 foot FOV!

Because God has put an upper limit on FOV. But if he ever relents I'd like those wide views to be in 10x.

[David Swain]

Originally Posted by SEOW

Holger Merlitz on the subject:

http://www.holgermerlitz.de/wide/wideangle.html

Holger puts it rather well:

"Wide angles are tough: Optical aberrations increase rapidly with the angle of view, and even a sophisticated design leaves a lot for the amateur optics tester to pick at and complain about ("poor edge-sharpness!") on the Internet discussion boards - something no high-end manufacturer likes to read about his product."



David

[SEOW]

Yes, I liked his take on that too (along with just about everything else he says there)

I'd say he's way, way off on FOV not being that important for birding though

[denco@comcast.n]

Originally Posted by SEOW

Yes, I liked his take on that too (along with just about everything else he says there)

I'd say he's way, way off on FOV not being that important for birding though

I agree. A big FOV is an advantage when following small warblers. I think in almost any case it is beneficial.

[denco@comcast.n]

Originally Posted by black crow

Because God has put an upper limit on FOV. But if he ever relents I'd like those wide views to be in 10x.

Exactly. A 10x with a 600 FOV. Now that would be something wouldn't it!

[denco@comcast.n]

Originally Posted by David Swain

Holger puts it rather well:

"Wide angles are tough: Optical aberrations increase rapidly with the angle of view, and even a sophisticated design leaves a lot for the amateur optics tester to pick at and complain about ("poor edge-sharpness!") on the Internet discussion boards - something no high-end manufacturer likes to read about his product."



David

Holger also says that it would be possible to make a modern SWA binocular in say an 8x40 that would outperform the older SWA porro's. It's just nobody has done it. What's the widest quality WA binocular available today outside of the Nikon EII?

[denco@comcast.n]

Originally Posted by FrankD

My limited understanding from what I have read would lead me to believe that prism size is the culprit. I am sure you have seen many of the lclassic porros that do offer huge fields of view. Almost all of them have huge prism housings to, well, house the large prisms. The larger prisms are needed to avoid any type of incursion into the light path.

How far off am I on this one Henry?

Since roof prism models have narrower bodies it would be difficult to create one with an extra wide field of view that did not have extremely fat barrels to accomodate the larger prisms needed.

"Almost all of them have huge prism housings to, well, house the large prisms."

Like these.

[black crow]

Originally Posted by denco@comcast.n

Exactly. A 10x with a 600 FOV. Now that would be something wouldn't it!

One of the best drugs ever.

[Steve C]

A $25.00 investment will get a non eyeglass wearer the fov experience. I don't think 600' is necessary, although it sounds nice. 11* or 578' for a 77* afov in a vintage 7x35 porro will illustrate this. What happens with 75-80* afov is that the edge almost goes away. Yes, you can still have perceptual awareness that there is a black border out there at the edge of the earth. However, you can't really see it. When you try to actually look at the edge, you basically can't. If you go, say to the left edge, your right eye gets black out before you get there, if you force the issue and keep going you see two edges...which one is the real edge?

This does a couple of things. First it puts the pre edge image softness out into the periphery of the field, where it should be. In effect, you have a magnified peripheral view with much less edge awareness. The second thing it does is cause an apparent widening of the sweet spot. If you have eyes with some accommodation, they will focus out a lot of the gradual field curvature in the softness of the image. ETA: Combine the above with the 3-D effect of the porro gives a pretty outstanding view in many respects.

You will need a porro with large prisms, American style rather than the smaller German/Zeiss style. A smaller prism porro with a 578' fov does not give the same impression of width as the larger. For one thing, they have a little more eye relief and you have to back off a few mm to avoid blackout. The closer you can get your eye to the ocular the wider things look. The large prism UWA 7x35's are a large double handful of binocular, small they really are not.

Eye glass wearers are out of luck here, you can't get close enough to the ocular to even completely merge the images. They are not for cold weather either, because with your eyes that close to the lens, there is a lot of external fogging potential.

I have been thinking about what one of these would look like with modern glass and coatings. After reading Holger, I agree with him. Another eye piece is needed too.

So, I don't think SV/EDG type sharp edges are needed, but a lessening of the softness of the image and widening the sweet spot would be a view to be seen.

The old porro will perform at surprising levels, but an alpha they are not. They serve to illustrate the fov phenomena quite well.

[Pinewood]

Hello Dennis,

I think this 11x50 8.5* binocular is what you would have to fulfill your wishes.

Happy viewing,
Arthur

[denco@comcast.n]

Originally Posted by Pinewood

Hello Dennis,

I think this 11x50 8.5* binocular is what you would have to fulfill your wishes.

Happy viewing,
Arthur

That's pretty cool! Two BIG Naglers. That would work good for astronomy on a tripod. The view would be great I'll bet.

[denco@comcast.n]

"So, I don't think SV/EDG type sharp edges are needed, but a lessening of the softness of the image and widening the sweet spot would be a view to be seen."

I agree I think it would create an awesome view. The sweet spot would be so huge you probably wouldn't notice the edges.

[brocknroller]

One thing that Holger didn't mention was that the Porro II prism packs more into less space.

Check out the prism shape and size in the 9.5* FOV Miyauchi 7x50 Binon. Nowhere nearly as big (or heavy) as the prism housings of the 6.5* FOV Fuji 10x50 FMT-SX.

Given this, I'm not sure why optics more companies don't use Porro II prisms for WF bins? Well, other than the fact that porros are considered déclassé these days.

Of course, the EPs are still humongous, but note the way Miyauchi indented the eyecups instead of taking them out to the edge of the ocular housing the way Nikon does with the SE series or Fuji does with the FMT series. More comfortable fit.

http://www.bigbinoculars.com/m750w.htm

Brock

[Pinewood]

Originally Posted by denco@comcast.n

That's pretty cool! Two BIG Naglers. That would work good for astronomy on a tripod. The view would be great I'll bet.

Dennis,

I think anything that would come near to fulfilling your wishes either would be tripod mounted or very unportable.

Happy bird watching,
Arthur Pinewood

[John Dracon]

I suspect that the number crunchers and optical designers have already conferred on the super wide sharp-to-the-edge binocular. Too many technical problems not to mention production costs and projected sales at astronomical prices have probably dampened their enthusiasm somewhat. If the world had millions of Warren Buffets, we would have witnessed this already, I believe. Dr. Merlitz's opinions combne both technical knowledge and extensive binocular use. It is no surprise, then, to learn of his recommendation of the 8x40 format for such a project.

For those of you not familiar with the older porro Bushnell 8x40s with Erfle lens, they are indeed very impressive binoculars. Some of us have wondered why Nikon hasn't slipped in its SE line an 8x42 by now. Much of the yearning for the super-wide-angle binocular would probably be satisfied with many users should this happen.

John

[etudiant]

Would it be possible to achieve a much wider field by sacrificing magnification?
Ideally, something along the lines of the old 6x Leica Amplivid, which had about 12 degrees field of view, but even lower power, with a correspondingly wider field.
For hawk watches, a wide field really helps and magnification is less critical, so 4x or 5x would be fine, ideally with a 15+ degrees field of view.
There is precedent for a 5x glass. Ross produced a large number of 5x air raid spotter binoculars which gave faithful service in WW2.

[ceasar]

Originally Posted by John Dracon

I suspect that the number crunchers and optical designers have already conferred on the super wide sharp-to-the-edge binocular. Too many technical problems not to mention production costs and projected sales at astronomical prices have probably dampened their enthusiasm somewhat. If the world had millions of Warren Buffets, we would have witnessed this already, I believe. Dr. Merlitz's opinions combne both technical knowledge and extensive binocular use. It is no surprise, then, to learn of his recommendation of the 8x40 format for such a project.

For those of you not familiar with the older porro Bushnell 8x40s with Erfle lens, they are indeed very impressive binoculars. Some of us have wondered why Nikon hasn't slipped in its SE line an 8x42 by now. Much of the yearning for the super-wide-angle binocular would probably be satisfied with many users should this happen.

John

AFAIK the three SE's are semi-modular. To save costs I guess. Their eyepieces and prisms and prism housings are the same. Only the objectives and their tubes change. An 8 x 42 SE would need an entirely new eyepiece and I suppose if you wanted it to be super-wide it would probably need a redesigned prism with a new housing. (Unless one of those Porro II prisms that Brock mentions would work.) But that is speculation on my part.

Bob

[Holger Merlitz]

Originally Posted by SEOW

Yes, I liked his take on that too (along with just about everything else he says there)

I'd say he's way, way off on FOV not being that important for birding though

Is that true? Birders would in fact appreciate having more field of view? In that case, perhaps, you should make a little more noise to be heard by the manufacturers.

In my opinion, the most recent improvements implemented by the high-end manufacturers concerned things like an increase of transmission by a few percent, improvements of edge-sharpness from 85% to 90% and so on. Small, but costly improvements with questionable impact on real life performance.

What I regard the most important parameter to be addressed in future upgrades is the field of view which hasn't seen any significant improvements during the past few decades.

Cheers,
Holger

[Kammerdiner]

Originally Posted by Holger Merlitz

Is that true? Birders would in fact appreciate having more field of view? In that case, perhaps, you should make a little more noise to be heard by the manufacturers.

In my opinion, the most recent improvements implemented by the high-end manufacturers concerned things like an increase of transmission by a few percent, improvements of edge-sharpness from 85% to 90% and so on. Small, but costly improvements with questionable impact on real life performance.

What I regard the most important parameter to be addressed in future upgrades is the field of view which hasn't seen any significant improvements during the past few decades.

Cheers,
Holger

I think most serious birders are not interested in ultra-wide field of view. They don't need it. They know their bins and they get on the bird fast. It's a matter of experience. Some folks around here never seem to use a particular binocular long enough to ever get the hang of it. No wonder they can't find what they're looking for and yearn for more field of view. What the heck do you need 600' FOV for if you're looking at a tiny warbler? Can't find it? Then you don't know your binocular. Newbie.

I've used birding bins from 262' to 477' and if I had to choose a favorite it would be around 400'. Really anything from maybe 350' to 420' in an 8-8.5x is just fine for me. Less is a bit fussy, more is a waste. That's my experience anyway.

Mark

[vop]

How can a wider field of view be a waste? If the field is too wide, you can always put extensions on the eyecups to narrow it down.

600ft/200m with edge to edge sharpness I understand... but a 400 is about the least I'd go for next time I buy a pair.

I'd like a 7x42 with about 500ft/170m FoV, and at least 75% sweat spot (really sweet), please!

[Kammerdiner]

Originally Posted by vop

How can a wider field of view be a waste? If the field is too wide, you can always put extensions on the eyecups to narrow it down.

600ft/200m with edge to edge sharpness I understand... but a 400 is about the least I'd go for next time I buy a pair.

I'd like a 7x42 with about 500ft/170m FoV, and at least 75% sweat spot (really sweet), please!

I'd call it a waste because it will probably be fuzzy and useless. There's the bird, front and center, and then there's all that wasted fuzzy stuff surrounding it.

If a warbler darts off--which is precisely what they love to do--even 1000' isn't going to help you much. You'll have to be a better birder. You'll have to know the birds.

Hunters don't have this problem, which is why they favor 10x and aren't so concerned with FOV. They look at stuff far away and relatively slow. Or else they're hunting stuff fast and close like grouse and pheasant, in which case a binocular is mostly window dressing.