A different set of four hand-held binoculars (1 Viewer)

[kimmik]

It is no secret who's thread inspired this post - @dorubird's essay made a lot of sense to me and I could see myself with the exact same set of four, but the way things worked out gave me a different but also satisfying complement of binos.



The biggest difference other than size, is that these represent each of the four modern prism topologies.

Porro - The Swarovski Habicht 8x30 W is my current go to. It has the sharpness you want from premium binoculars, but adds to it the perfect transmission character, and an image cleanliness that Porro so effortlessly offers. The eye relief took me some time to familiarise myself and even though I wear spectacles, I find it fun both used with and without. Things like glare and stiff focuser, are only a problem if you make it a problem - at the park today looking near the winter low sun, warm orange flares can be made at specific angles, remind me of photographs taken to deliberately produce lens flare and gives extra character to this otherwise perfectly neutral image. 4mm pupil, made in Austria.

Reverse porro - The Pentax Papilio is possibly the most deserving model of this format, by using the closely set objectives to its advantage, focusing closer than 0.5m when others can manage 1.5m at best. The transmission isn't as high as premium compacts being around 85%, but in summer looking at flowers and insects will not pose a challenge. The Porro cleanliness is also visible when put side by side with a more compact roof. The synchronised ipd adjust does make it easier to use. 3mm pupil, made in China.



Schmidt Pechan roof - The Leica Noctivid 8x42 is the smallest full feature binocular of the set, and is the one that produces the most beautiful autumn foliage and skin tones. The slight warmth also cuts through haze, adding to the excellent contrast and black point of a well baffled design. This pair gets a good share of use especially for when the arms are strong but the eyes want a rest. The 5mm pupil coupled with long eye relief takes any strain away and puts less pressure on the glasses. Made in Portugal

Abbe Koenig roof - The master of the house, the commander of the ship, the one that does it all and makes no compromises, SLC HD 8x56. This traditional full sized full cream extra organic animal of a binocular, is the one that keeps the rest in line. Too dim? never. Too shakey? never. Sharp? just point at it. No rolling ball, least black out, can be used with whatever fancy glasses and goggles you wish. Thick armour and excellent weight makes it feel strong and tough. It might not be used the most often due to the degree of excess, but the set would not be complete without it! My ultimate big eyes experience. 7mm pupil, made in Austria.



But the set may not stay at 4 forever, as there is no 10x pair which I have decided to buy, when the right specifications appear. It needs to be 10x42 with 70degree+ AFOV, and needs to be Zeiss made in Germany. Within 5 years what do you think? Surely NL will not be taking the spotlight for that long!

As for where are the other binos that I've mentioned previously, they are all in good hands or will be when the time is right. The NL 8x42 with CL 7x21 makes a fantastic two-bino set, exceptional light throughput for their weight, and widest true FOV of their respective classes. The EL 8x32 is amazing as a one-and-done, so it will probably go to a younger person to get the hobby started...

 

[Will K]

Lovely collection!

I’ve never looked through a Habicht, but there’s so much love for them on this forum, I need to check one out one day!

 

[Scott98]

Abbe Koenig roof -

You forgot to say who the "Master and Commander" is, but I think we can extrapolate - SLC 8x56.

So you think a successor to the Zeiss SF is coming soon? I think the 10x42 SF is 68 degree AFOV? so not too far off your goal

 

[kimmik]

@Scott98 woops, added in haha.

Hmm SF is listed as 64deg afov by zeiss, but I haven’t tried to confirm it, sounds about right for a field flattened binocular. Pure speculation on my part that 2025 or so will be 10years of SF, and 5 years of NL, a good time to introduce the next victory and set a new benchmark.

 

[Scott98]

it's weird, Zeiss specs say the AFOV is only 64 degrees, but allbinos measures the 8x42 and 10x42 SF at 67 and 68 degrees and that's what it looks like.

Will be interesting to see what happens next, they have to do something to make people with older binos upgrade to the new ones. Not much room for wider field. I'm hoping the 54mm's HT's are the ones replaced by the next upgrade from Zeiss.

 

[Tringa45]

What an ode to the 8x56 SLC!
After over two years of ownership the viewing experience surprises every time I pick it up, even though I am no longer able to make full use of its twilight capabilities.
Large exit pupils inevitably involve weight penalties and although many question their usefulness, I have never read a post in which a user denied their qualities.

John

 

[Conndomat]

it's weird, Zeiss specs say the AFOV is only 64 degrees, but allbinos measures the 8x42 and 10x42 SF at 67 and 68 degrees and that's what it looks like.

Quite simply because allbinos uses the simple formula, in fact this formula is practically always too high!

Andreas

 

[kimmik]

It may be a coincidence, or a clue to how my brain and eyes work, but the four binoculars have FOV of 7.5 (papilio), 7.6 (slc), 7.7 (noctivid) and 7.8 (habicht). If the future 10x42 has 7.4deg FOV would fit right in. Something about keeping the true FOV similar, makes switching between them easier and more natural, even if the magnification and eye relief differs. These also have generally conventional field curvature and pincushion distortion.

 

[Scott98]

Quite simply because allbinos uses the simple formula, in fact this formula is practically always too high!

Andreas

What happened to just mulitplying the FOV by the magnification to get the AFOV?? I think the 8x42's true FOV is 8.4 degrees...so 67

 

[kimmik]

What I don’t understand, is why AFOV specification is often calculated and estimated when it is so easy to measure the actual value.

True FOV x mag is only correct for afov if there is uniform angular magnification, but not all binoculars take this approach.

NL 10x42 has 7.6degrees true, but not 76degrees Apparent. It has 70degrees apparent.

 

[GrampaTom]

What I don’t understand, is why AFOV specification is often calculated and estimated when it is so easy to measure the actual value.

How is that done please?

 

[Tringa45]

How is that done please?

A simple and precise method of measuring AFOV

Speculation about the AFOV in a recently linked binocular test prompted the following:- AFOV is often calculated by multiplying true FOV by magnification, e.g. 10 x 6,4° = 64°, or using the ISO standard, which for the same binocular (112 m @ 1000 m) gives 58,5°. However, angular magnification...

www.birdforum.net

 

[Conndomat]

What happened to just mulitplying the FOV by the magnification to get the AFOV?? I think the 8x42's true FOV is 8.4 degrees...so 67

Quoting @Holger Merlitz

the confusion arises from the contradictory information provided by the manufacturers. While the objective viewing angle can be precisely converted into
the field of view, calculating the subjective viewing angle requires knowledge of the distortion, as John Russel already mentioned. Unfortunately, the manufacturers do not specify the distortions of their optics. Alternatively, they could at least publish the actual subjective viewing angles, but only a few do that (Swarovski and Zeiss only with their SF series, but not with the other models!). In all other cases, they use standard conversion formulas that either overestimate or underestimate the subjective viewing angles.

The ISO 14132-1:2002 conversion formula consistently used by Nikon is
a = 2 atan[m tan(A/2)] (1)

where 'a' is the subjective angle of view and 'A' is the objective angle of view and 'm' is the magnification. This formula only applies in the absence of distortion (strictly speaking, in the absence of radial distortion V), and this condition is almost never met in practice. In the presence of radial distortion, the above formula must be expanded to

a = 2 atan[m (V+1) tan(A/2)]

where 'V' indicates the relative radial distortion at the edge of the field of view. If this is equal to zero, then you immediately get the ISO formula again. V is almost always a positive number, in which case one speaks of pincushion distortion. Too bad that no manufacturer specifies the value of V. A special case is of interest, namely the so-called angle condition, in which

tan(mA/2)
V = ------------ - 1 (angle condition)
mtan(A/2)

is applicable. This leads to the well-known simple conversion formula

a = m A (2) (angle condition)

It can be shown that this special case, if it is fulfilled for every pixel, leaves the angular distances of all pixels unchanged when panning over the entire field of view. In astronomy, this means, among other things, that an open star cluster is displayed in the center of the image in exactly the same way as it is at the edge of the field of view (if the eye follows the position of the star cluster as it pans to the edge of the field of view). In the English-speaking world, one then speaks of the absence of an 'angular magnification distortion' (AMD) - for which there is apparently no specific expression in German (one could casually speak of 'angle distortion').

Historically, manufacturers have initially aimed for distortion-free imaging (V = 0), but since about 1950 they have increasingly relied on the angle condition (where V > 0 and there is clear pincushion distortion) in order to avoid the globe effect when panning the binoculars. In almost all binoculars currently on the market, the value of the distortion is somewhere between V = 0 and the angular condition, so neither (1) nor (2) reflect the correct ratios. We then have no choice but to measure the apparent viewing angles ourselves.

How is that done please?

Quoting @Tringa45

The best way to measure the AFOV is to measure it, and I've simplified Mr. Schön's method a bit (no laser, wizard, or complicated calculations). Mount the binoculars horizontally on a tripod, set the focus to infinity, and aim the eyepieces at a distant edge of a building. Viewed through a lens, one notes the degree measurements on the panoramic head where the edge of the building just disappears to the left and right. The AFOV is the difference between the two readings. At distances of around 50 m or more, the parallax error caused by the swiveling of the eyepiece is negligible.

My Swarovski 10x42 EL SV has a viewing angle of 6.4° and a field of view of 112 m @ 1000 m. The two calculations result in an AFOV of either 64° or 58.5°. With the above measurement method I have confirmed the Swarovski specification of 60°.

What I don’t understand, is why AFOV specification is often calculated and estimated when it is so easy to measure the actual value.

Quoting @Holger Merlitz

I've often asked myself why the manufacturers calculate their viewing angles with inaccurate formulas (instead of simply stating the laboratory values) and never received a convincing answer. As long as the angle condition was used consistently, the subjective viewing angles were usually overestimated - so it stands to reason that marketing could live well with this approximation. However, it is no longer understandable that Nikon systematically underestimates its viewing angles with the ISO formula. For the 10x50 WX they determined a viewing angle of 76.4°, while the actual value should be around 83°. They didn't accept my suggestion to simply publish the measured data...

Quoting @Conndomat

I hope the questions have been answered sufficiently?!

Andreas

 

[Conndomat]

A simple and precise method of measuring AFOV

Speculation about the AFOV in a recently linked binocular test prompted the following:- AFOV is often calculated by multiplying true FOV by magnification, e.g. 10 x 6,4° = 64°, or using the ISO standard, which for the same binocular (112 m @ 1000 m) gives 58,5°. However, angular magnification...

www.birdforum.net

Oops, I could have saved myself the hours of searching...

Andreas

 

[GrampaTom]

Thank you! Thank you John and Andreas. The Nikon published explanation, with sketch and the simple formula has never done it for me. Awesome.

 

[Scott98]

a trick I learned from astronomy eyepieces to compare AFOV is to hold two different oculars up to your eyes, and gradually move them into the correct position - where your eye sees the field stop. You don't have to focus. You can move the two circles around, merge them & move them apart again, and quickly see the difference in the AFOV by the size of the circles.

I do the same thing by holding one barrel of 2 binoculars up to each eye. So if you know the AFOV or 1 or 2 binoculars, you can see the relative difference and estimate the AFOV of another bino. They can be different magnification, it doesn't matter.

 

[dorubird]

Scott98,
I do the same when comparing two binoculars. The difference is much more eloquent for the eye than reading only the writing in the specifications!