What’s the use of extra wide FOV (if you can’t see it) (1 Viewer)

What's the use of sharp edges?

Does anyone look at binocular edges to ID/admire a bird (not mentioning stars)?

I love wide angle. If you have ever looked for diving birds or breaching whales and dolphins, or a fast moving bird through dense foliage, and are eagerly anticipating the moment said bird / dolphin would come into view again by trying to track the location it should reappear for (sometimes) a split second, you realize how much difference a wide field can make.

It's easy to critisize bad wide angle binoculars. But using that as an argument to critisize all wide angle binoculars, is a bad argument. There are good wide angle binoculars, stick to those.

Life is too short to critisize bad binoculars, be it wide field or tunnel view.

temmie said:

Life is too short to critisize bad binoculars, be it wide field or tunnel view.

Click to expand...

Temmie, maybe I didn't make my point clear enough. My idea/test is far from trying to critisize bad binoculars, just stating a surprising fact I've discovered (in my case), that I just can't make use of the wide FOV of some binoculars, when that particular feature is actually one of their main selling points. The EII is by no means a bad binocular (is actually my favourite binocular! ), but I just can't use the 8,8º FOV (and I don't wear glasses); Binastro, on the other hand, seems to be able to enjoy the full FOV, and even more. Is just about sharing experiences

Binastro said:

This morning I tried the Nikon EII 8x30.
It was bright sunshine so my pupils would be small.

Both field stops are easy to see. They are sharp.
The binocular gives a beautiful view and is very bright. Too bright this morning. I would have liked neutral density filters.
Eye placement is very easy for me with the EII unlike the Nikon 8x32 SE.
The eyecups were fully up on the EII.

Click to expand...

That's both interesting and surprising. With a "relaxed and natural" viewing position I cannot see the field stop with eyecups up. If I crush the eyecups against my eye sockets, I can (if I push hard enough) reach to see the field stop, but that position is simply a pain It seems that facial features may play a big role in how much FOV you can see (?).

yarrellii said:

Chosun. Wow! I think I had to read your comment at least 3 times before I could try to understand the logic behind. Not your fault, I'm a mess when it comes to maths and geometry (I studied Humanities!). However, I think I you might have taken my aim too seriously (or my skills to highly!). The little test was just a simple game to show what I can see through different binoculars, and the relationship with their claimed FOV (and the conclusions or discussions derived from the results).

As a general note, I don't wear glasses, so I've never used binoculars with them (I assumed, I don't know if incorrectly, that without glasses you are generally speaking in a "easier" starting point to enjoy full FOVs). Sometimes I try to mimmic the experience of using glasses (just to try and get a feeling of what that might be like) by using the binoculars with my sunglasses on, and the result is quite disappointing. I guess sunglasses are not meant to have good bino-using performance.

Anyway, back to the topic. I'm very interested in your bit that says "At the correct ER setting you should be able to see the full Fov". Is that a expression of desire/wishful-thinking or is it the way it should be? (I'm asking from the humble standing point of plain ignorance, no second intention intended). If this is the case, I'm not sure if it is just me and my eyeballs, or there's something wrong with superwideFOV binoculars. Take the 8x30 EII, for example. There's no way I can see the field stop without leaning sideways, even with the eyecups fully down and my eyelashes brushing the eyepieces (let alone with eyecups up). And I don't even want to start talking about what happens when I try to look for the field stop in the 11º FOV Minolta. I have to lean sideways so much, that I simply loose the "roundness" of the image and by the time I see the sharp field stop I see little more than a crescent of image (find attached a "dramatization" that shows more or less what happens).
I am aware that there are many EII 8x30 users among forum members. It will be interesting to know how many (if any) actually see the sharp field stop when using their binoculars "naturally" (without hoovering or leaning sideways, so to speak).

Always interesting to read your comments, really informative and enlightening

Click to expand...

Yarrellii,

I've flicked through the thread a bit, and a few folk have pointed out the limitations. I'm pretty sure most of your issues centre around Eye Relief. When you say you "lean", I gather you mean that you look sideways across the eyepiece - not lean your body sideways !

As Bill has said there are fundamental physics limitations to providing all the bells and whistles. You can have an extra wide apparent field, well corrected aberrations, long Eye Relief, light weight, and low cost --- but not all at the same time ! :eek!:

Binastro raised the factor of an individual's physical characteristics, and this certainly plays a big part in how well a binocular can be adjusted to fit you. What is very seldom mentioned around here is that most people's facial features aren't symmetrical - so you need to carefully adjust ER, and IPD for not only your face, but viewing distance too with a Porro. Also make sure the diopter is set correctly for you. It may also pay to check that your binoculars are functioning correctly - optical centering, collimation, focus precision (no hysteresis) , etc.

(You can check the EP's for roundness by moving a sheet of paper perpendicularly back from the ocular with a light source [sunshine etc] shining through the objectives - you can measure the ER distance when the circle becomes a focused minimum Exit Pupil [Objective diameter ÷ magnification] roughly. You will also get an idea of how critical it is - or how much margin of error in other words).

In addition to getting all the above set correctly, and checking that it is functioning within spec, David mentioned that there are other unknown factors affecting the ease of view - things such as focal accommodation, Spherical Aberration of the Exit Pupil, Truncation of the Exit Pupil due to undersized elements in the optical train, the Randpupille qualities of the design, etc, just to mention a few.

You could really do your head in speculating about it all. The best way to cut through the confusion is to set the bins up correctly for you, and then get that 10m builder's tape measure out, find a brick wall, or fence, some chalk, and just do a few simple measurements - do the simple trigonometry (itself a small angle approximation) and then compare to stated specs. Then you will know for sure. :t:

As Hermann, Jring, and others have said - most folk should be able to detect 60° out to ~80° to 90° AFov. There is research to back this up. Everybody is an individual of course but I think we can say that the wide angle Wow kicks in at around a well corrected 70°, anything under 60° can feel a bit tunnel-like, and over ~90° can perhaps start to feel a bit weird for some people.

Good luck !




Chosun :gh:

With 8x30E2 I can see the edges easily, same with 7x35 bushnell rangemaster 11degree, though I do need to wipe my eyeballs against the glass to use them properly.... intimate views?!
I recently got an 70mm APM binocular telescope and use 82degree Nagler eyepieces for birding, these make the view of the E2 feel claustrophobic with very blurry edges. There are other similar eyepieces with better eye relief (And less distortion) if I ever need them. You just lose the feeling you are looking through anything. You can’t go looking for the sides of the field as turning your eyeballs means one eye is then not looking down the exit pupil (only got about 3mm exit pupil on these). Looking up and down is easier to see the field stop.
Having sharpness to the edge is useful as when used at night and you pan about, having stars constantly growing and shrinking as they go past can get annoying!
Got to say I’d love some 6-7mm exit pupil 7-8x binoculars with 80degree Apparent field of view... likely impossible to realise or to use (unless you don’t have a nose).

PEterW

wllmspd said:

Got to say I’d love some 6-7mm exit pupil 7-8x binoculars with 80degree Apparent field of view... likely impossible to realise or to use (unless you don’t have a nose).

Click to expand...

Hi,

yes, it will be a bit difficult...

TFOV in deg = 180/PI * EP field stop / objective focal length

Since we're looking at 80 deg afov at 8x or roughly 10 deg tfov, we need with your APM 70/400mm bino as an example

10 * PI / 180 * 400 = 70mm or a tad over 2.7"

The barrel size needs to be in the same ballpark which makes the interpupilary distance too wide for most.

The 16mm Nagler you used in your APM 70/400 was probably your widest 1.25" option for 80 deg afov.
Or maybe Baader Morpheus 17.5mm - you trade a better eye relief against 6 degree less afov and a 55mm outer diameter - which might be problematic for people with narrow IPD and a strong nose...

Joachim

Yep, 16mm ultrawide or 24mm sort of wide is the best I can hope for. Looked at options for bigger reflective binoculars, but the lack of coma correctors and secondary obstruction become issues. https://analogsky.co/ is working on a commercial 8” unit, should be great for night usage.

Peter

Peter,
I wouldn't fancy collimating large reflective binoculars.

Several people have made nice binocular telescopes using secondhand 6 inch f/8 Skywatcher refractor tube and optics, and mirrors at the back.

Personally, I have never been attracted to large binoculars.
I much prefer a larger telescope.
Much less complicated.

Regards,
B.

wllmspd said:

Yep, 16mm ultrawide or 24mm sort of wide is the best I can hope for. Looked at options for bigger reflective binoculars, but the lack of coma correctors and secondary obstruction become issues. https://analogsky.co/ is working on a commercial 8” unit, should be great for night usage.

Click to expand...

Hi,

you will not get any larger true field of view though with a bigger binoscope... plus getting them collimated is a major pita.

I mean for night use, a bino dobsonian is really great - had the privilege to enjoy the view through a 13" example at some star party... it was quite breathtaking. I needed to remind myself that the owner had spent quite some hours fiddling with collimation before to come back to senses...

I would probably be more drawn to some 100 or 120mm astro bins... less hassle... otoh two guys from the club have 120mm APMs so I get to enjoy those from time to time...

Joachim

I remember the first time I looked (at a perched Red-tailed Hawk) through a Swarovski 8X32 EL SV with its 8 degree field of view.

I was stunned.

I owned the Minolta 7x35 Standard for a couple of months and noted my impressions in this thread: https://www.birdforum.net/showthread.php?t=350877. It didn't have enough focus beyond infinity to compensate for my myopia (not really the binocular's fault) and I personally could not see any greater field of view with it than with a 7x42B Dialyt, so was not too surprised that the original poster found the Nikon 8x30 EII gave him a greater field of view.

My current 7x35 extra wide is a Swift 766. I haven't tested its field of view against the 11 degrees claimed, but it's noticeably wider than the 7x42 Dialyt and my 8.5 degree 8x30 porros. I can see the field stop quite well - incidentally, I am a little confused by the original poster's statement that "my eyeballs were literally touching the glass on the eyepieces long before I could even reach to see the field stop", as the field stop ought to get further out the closer your eye gets to the glass? It's a good bit bulkier than the Minolta, but the bulky body accomodates the large prisms needed to provide that field of view. Center sharpness is very good. Edge sharpness is interesting, in that at shorter distances it falls off, to my eyes, quite similarly to the 8x30 Binuxit, that is to say, quite acceptably. At long distances the sweet spot is smaller and edge performance worse - but this may well be influenced by the fact that, as with the Minolta, although to a lesser (though still noticeable) extent, the big Swift's focus does not go enough beyond infinity for me to get the left barrel tack-sharp on distant targets. (I have the same problem with quite a few binoculars, including the EII.) I really ought to get its focus adjusted by a professional. I'd gladly give up close focus for extra focus beyond infinity.

I've read some suggestions that the various JB extra wides (my Swift is a JB-26, Futaba) may have had different eyepiece designs. Those with the widest field of view may well, as Hermann mentions, have had the tightest eye relief and the most compromised edge performance.

Extra wide field of view isn't totally necessary, but is very useful to have, especially when scanning around in search mode. My most memorable experience with the Swift 766 was following a peregrine tiercel flying out to hunt a high-flying pigeon. As he closed in on his quarry and some incredible high-speed manoeuvering ensued, I remember very well how easy it was to capture those amazing acrobatics within the big 7x35's generous field of view. I'm perfectly fine with not being able to see the field stop - I think it makes the view more immersive. I get that effect with Nikon's 10x50 WX, which combines great field of view with excellent edge performance - an amazing optical device but, alas, also very bulky and costly.


PS. I also have the Zeiss West 10x50 Hermann refers to and it works well for me, too. No trouble seeing the full field of view. If only this superbly manufactured classic had made it into the T* multi-coated era...

Made another convert to Very wide field views last night under the stars... which are very good at getting fuzzy and showing up the issues with your optics!

Peter

Patudo said:

PS. I also have the Zeiss West 10x50 Hermann refers to and it works well for me, too. No trouble seeing the full field of view. If only this superbly manufactured classic had made it into the T* multi-coated era...

Click to expand...

Zeiss did a special (anniversary?) re-issue of that glass sometime in the 1980s. I've never seen one, and always wondered whether it had multicoating.

Minolta MK Standard 7x35 11* EWA

Yarelli Patudo

[Forgive me if I in part repeat what I have said in previous threads where we have each, as I recall, also posted]

I think people's issues with the Minolta MK Standard 7x35 11* Extra Wide Angle binocular may largely have to do with the distinctive ergonomics, namely, as I understand them to be, near-zero eye relief (and possibly also wide ocular lenses and eyecups) of the 7x35 EWA specification as implemented by Minolta.

I bought a Minolta about April 2017, and immediately, thanks to the compatibility with it of my personal ergonomics, got the full field of view simply by turning down the eyecups.

Here are my measurable ergonomics:
* Inter-pupillary distance: 64mm
* Maximum width of nasal bone: 20mm

According to some American study data that I have read, the IPD is close to the adult male average. The width of nose is though almost certainly more--possibly significantly more--narrow.

The dimensions of the eye socket, or of the set of the eyes, are not conveniently measurable or usefully describable.

It goes without saying, given the lack of eye relief of the Minolta, that I don't wear spectacles when using it*.

Otherwise, as to the rest of my experience with the Minolta, the resolution of the image in the outer field remains sufficient for relaxed observation well out towards the field stops. The image of the edge of the field stops is though certainly blurred.

I occasionally experience small blacks, but unlike eg the blacks that I used to experience with the ergonomically admittedly very different Swift Osprey 7.5x42, they don't bother me in use.

When for instance tracking a foraging small warbler, or observing several interacting small birds, I rove the field of view without recentering almost as freely as I do the field of view of a good 7x50 (in my case, a recently purchased Zomz 7x50).

I don't find contact of the eyelashes with the ocular lenses to be a big issue, although others definitely might. Puzzlingly, the ocular lenses don't seem to dirty quite so quickly as the ocular lenses of the ergonomically similar Opticron 8x32 SR.GA. My usage of the two binoculars though is different: I use the Minolta most frequently as a house binocular; the Opticron most frequently as a field binocular.


Stephen


* The diopter corrections of my spectacles, should the state of my eyesight for some optical reason be relevant, are:
- Correction of spectacles for distant vision: Right +1.00, Left +1.25
- Correction of spectacles for intermediate vision: Right +2.75, Left +3.00

In a general sense, there is not much use for these extra wide FOV binoculars. The only ones that
are well known are the older Japanese made porros from the 50's and newer.

The wide FOV is in name only, as they only offer a smallish sweet spot, the outside is fuzzy and not usable.

Jerry

NDHunter, you haven’t tried the 7x35 11degree Bushnell Rangemaster then? Considered the equal of the Nikon 8x30E2? Very deep depth of focus too. Only downside is they are a bit weighty.

Peter

wllmspd said:

I recently got an 70mm APM binocular telescope and use 82degree Nagler eyepieces for birding , these make the view of the E2 feel claustrophobic with very blurry edges.

PEterW

Click to expand...

I take my hat off to you sir - isn't that a 3.3kg unit? What magnification would these eyepieces be, and can you tell us more about how that big Astro kit performs in daytime use?

Yes, 3.5kg, but a comfortable daytime backpack carry with a tripod, bit like a BTX, but with much wider views. Main eyepieces are 13mm naglers for 30x (better options exist). I am about to get some higher power ones for brighter days, when you need smite reach. Everyone who has looked through them likes the view. Sharp across the wide view (nikon 8x30 E2 are claustrophobic with fuzzy edges in comparison). Best for hide/static use, individual eye focussing is not ideal for panning about too much, but is easy to get used to. They do sell larger models, but then they weight a lot more and need a much heavier.
Not for everyone, but the views are great.

Peter

I'm sure they are, and would certainly like to have a look through them! Where do you do your birding - I recall you mentioned the London Wetland Centre some time back? I visit every now and then. It'd be interesting to try your Rangemaster alongside my Swift too!

Minolta MK Standard 7x35 EWA

Yarelli

To expand what I said about being able to rove the entire field of view without re-centering, which I find to be a useful feature of the Minolta MK Standard 7x35 EWA*, I have now conducted a general test of the optical performance in my hands of the Minolta.

It's a limited, rough and ready test, because optics is not my field, but here goes with the result:

Resolution is good almost right out to the field stop. Fine focus is progressively lost starting about half way out (5/10) from the centre of the ocular lens. At about 8/10 the loss of focus becomes more pronounced, with appreciable loss of detail, but continued preservation of pattern and silhouette. At the field stop (10/10) detail has for the most part been lost, and silhouette has become blurred, but the image is still usable. I can still make out strong pattern (eg the pattern of a Great tit or Goldfinch), and I can of course, as one would expect from the list of the sensitivities of peripheral vision, detect movement.

Field curvature, as I understand from posts on Bird Forum, is the likely cause of the progressive loss of focus. Thus I can restore good resolution right out to the field stop by a slight rocking of the focusser. The focusser of the Minolta turns fast, but its motion is damped by an adequate provision of friction. The rocking action can be accordingly be performed rapidly without loss of precise control.

The cumulative result of the above aspects of optical performance is, to present point, that, once the rocking of the focusser becomes intuitive, the eyes can rove virtually the whole of the field of view the Minolta without re-centering.


Stephen


* In close to near observation, the timing of the sequence 'Spot - Lay on - Accommodate - Focus - Appreciate' is often critical. Should one fail to lay the binocular precisely on the bird, roving the field of view may in favourable circumstances locate it more quickly than re-centering