seeing detail: good 12x50 vs. really good 10x42? (1 Viewer)

I'm trying to understand the tradeoffs between quality glass of 10x and lesser quality of 12x for identifying a dog breed 1.5 miles away in full daylight. I just want to understand the concepts.

Let me give you a real life scenario: On my deck on the hill. 1.6 miles away is a popular beach. I see two people walking and what I think is a dog. Can't tell whether the people are male or female, or what kind of dog it is. This is through a Chinese made Olympus 10x42 EXWP I. I say Chinese made b/c it does not seem to perform anything like the Japan made EXWP I of 13 years ago that got very good reviews. For the sake of argument let's just say my current binos resolve in betwen a Vortex Diamondback and Viper, or maybe even Monarch 5.


Assume tripod use, so shaking isn't an issue.
Also assume it is middle of the day and not a low light situation.
Also assume my target is fully within the center 20% of the FOV.

Let me use what I think is a fair comparison by keeping exit pupil somewhat equivalent:

Vortex Razor 10x42 (Japan made or China made)
vs. Vortex Diamondback 12x50

Or if you prefer:

Nikon Monarch 7 10x42
vs. Nikon Monarch 5 12x50
-or- vs. Monarch 3 12x50
-or- vs. Action EX 16x50

or if you prefer:

Maven B1 10x42
Maven C3 12x50

Will the 10x superior optics have a better chance of telling me what kind of dog is on that beach than the 12x lower quality optics, or 16x even lower quality optics? Or is the glass difference so small that magnification will trump a higher quality glass?

DunninLA said:

I'm trying to understand the tradeoffs between quality glass of 10x and lesser quality of 12x for identifying a dog breed 1.5 miles away in full daylight. I just want to understand the concepts.

Let me give you a real life scenario: On my deck on the hill. 1.6 miles away is a popular beach. I see two people walking and what I think is a dog. Can't tell whether the people are male or female, or what kind of dog it is. This is through a Chinese made Olympus 10x42 EXWP I. I say Chinese made b/c it does not seem to perform anything like the Japan made EXWP I of 13 years ago that got very good reviews. For the sake of argument let's just say my current binos resolve in betwen a Vortex Diamondback and Viper, or maybe even Monarch 5.


Assume tripod use, so shaking isn't an issue.
Also assume it is middle of the day and not a low light situation.
Also assume my target is fully within the center 20% of the FOV.

Let me use what I think is a fair comparison by keeping exit pupil somewhat equivalent:

Vortex Razor 10x42 (Japan made or China made)
vs. Vortex Diamondback 12x50

Or if you prefer:

Nikon Monarch 7 10x42
vs. Nikon Monarch 5 12x50
-or- vs. Monarch 3 12x50
-or- vs. Action EX 16x50

or if you prefer:

Maven B1 10x42
Maven C3 12x50

Will the 10x superior optics have a better chance of telling me what kind of dog is on that beach than the 12x lower quality optics, or 16x even lower quality optics? Or is the glass difference so small that magnification will trump a higher quality glass?

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Hi, my friend:

It looks like you are needing a simple mathematical answer. Sadly, optics doesn’t work that way. The first thing to recognize is that you must define: “good,” “really good,” AND “dog.” I am used to being thought of as always over the top. But if that raises the bar of understanding ... so be it.

The binocular is made of MUCH more than most popular articles relate, and every aspect weighs in. Then there’s the consideration for the atmosphere between you and your subject, the alignment of the instrument, and your personal visual acuity. Finally, the Irish wolfhound and “Miracle Millie” (the tiniest Chihuahua are both “dogs.” But I would venture you could make out the particulars of one before the other. Depending solely on mathematics, the 10-power binocular is going to make the dog appear 528 feet away. Could you determine what you wanted to with a view from that distance with the unaided eye? Now figure in atmospheric conditions, extraneous light, your visual acuity, the size of the dog, and more.

Again, based on math, the 12-power bino would bring you to a distance of 440 feet. That’s much better. Or, is it? Because of the increased magnification, resolution SHOULD be increased. However, that increase in magnification will take a toll on contrast, by accentuation both atmospheric and physiological conditions, which in turn will affect resolution.

In minutes, you will undoubtedly get advice to buy this or that, and I would encourage you consider that advice very well. I’m just a long-time optics geek who would like you to understand that there is MUCH more to your question than you probably realize. In optics, one size does not fit all. In real life, I see people overthinking their optics all the time and I like to keep things simple. I just want to offer a little something to POSSIBLY think about ... OCCASIONALLY. :cat:

Bill

WJC said:

Hi, my friend:


based on math, the 12-power bino would bring you to a distance of 440 feet. That’s much better. Or, is it? Because of the increased magnification, resolution SHOULD be increased. However, that increase in magnification will take a toll on contrast, by accentuation both atmospheric and physiological conditions, which in turn will affect resolution. I just want to offer a little something to POSSIBLY think about ... OCCASIONALLY. :cat:

Bill

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:t:

Hi DunninLA,

(The last few days the BBC have been flogging LaLa Land movie), O.K. I suppose.

The answer to your question is, Neither.
Use a scope, and a good one at that.

A person at 1 mile is seen to average eyesight, about 1.5ft wide by say 5ft 9 ins tall or so if standing.
If a relative resolution possible. Stranger, doubtful.
I used Herne Bay pier before it burned down, as it was about a mile long.
Either unaided eyes or 3 inch refractor or 25-40x55 Broadhurst Clarkson drawtube scope. Good teenage eyes.

1.6 miles is about 8,400ft or 2,800yds.
10 times nearer is 280yds. I think most dogs would not be clearly identified.

My selected 12x45 Russian binocular clearly, easily and repeatedly outresolves a Nikon 10x35 EII hand held.
This is because the 12x45 is long and beautifully balanced.
However, a Canon 10x30 IS with IS off showed Mizar as double as easily as the Russian 12x45. 14.4 arcsecond unequal double star. both binoculars very well braced.

The Fijinon 14x40 IS easily outresolves a Canon IS 10x, even though the Canon has a better stabiliser.
The Canon 18x50 IS outresolves anything hand held, except a Zeiss 20x60S, which easily beats it.
The Yukon 30x50 folded refractor binocular equals the Zeiss 20x60S.

In my opinion a low quality, but good condition 12x50 binocular will equal a good 10x50 and probably a good 10x42.
A 16x50 Nikon Action or Aculon will outresolve a top quality 10x50.

But it has to be a scope for dog identification and assuming it is not thick fog, driving rain or awful heat haze.

DunninLA said:

...Will the 10x superior optics have a better chance of telling me what kind of dog is on that beach than the 12x lower quality optics, or 16x even lower quality optics? Or is the glass difference so small that magnification will trump a higher quality glass?

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Just for this purpose, it may be the quality of the centre field, seen by both eyes in combination, which matters, but the 'glass difference' may not be that small.

The main thing might be that if the binoculars are cheap there is a greater likelihood for the barrels to be misaligned. If you were lucky they would not be, but if they were the image would be hard to focus, or harder to keep in focus, relying entirely upon adjustment by muscles of the individual user's eyes.

Alignment aside, near the centre the cheap ones are likely to be ok for focussing ability, but the point remains that cheap binoculars would tend to vary more.

Dunnin,

Firstly just a few numbers to think about.

With average 20/15 eyesight and high quality 10x magnification you should just be able to read Snellen standard letters 10" tall at 1.5 miles. At 12x that might improve to about 8.5" tall. Not easy to translate that into dog features, but probably enough to tell a difference between long or short haired and maybe upright or floppy ears, but probably not much more. 20x might get you to head shape and eye placement which might be enough to be reasonably confident of the breed?

Unfortunately the very good 20x binoculars tend to be rather expensive, but something like the Opticron MM4 60mm scope with the eyepiece of your choice should come in well under the price of a Vortex Razor HD, and give you a bit more flexibility on magnification and exit pupil to suite the conditions.

David

ABSOLUTELY agree with David....a spotting scope is the way to go. It will make all the difference in the world.

DunninLA said:

Let me give you a real life scenario: On my deck on the hill. 1.6 miles away is a popular beach. I see two people walking and what I think is a dog. Can't tell whether the people are male or female, or what kind of dog it is.

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1.6 miles (2.57km) is a considerable distance. If I needed to tell whether I was looking at a saluki or a greyhound at that range (or while I was at it, if the comely lifeguard on the beach is Pamela Anderson or Carmen Electra...) ... I would bring out your spotting scope.

Re. Post #1.

I just spoke with a top dog trainer and dog specialist and asked at what distance a medium size dog breed could be identified.
He said that it is impossible to generalise. There are many clues as with identifying birds.
It depends on a person's eyesight.

Or identifying cars.
Our panel beater could identify a whole row of cars along the street just from their side panels. I didn't have a clue usually from just this.

Anyway, with dogs, he says there are many different breeds of doberman, for instance. I asked if he could be sure at 100 yards. He said no.
50 yards, yes.
This is with unaided eyes.

So taking 50 yards for an expert.
1.6 miles is about 2,800 yards.
In perfect conditions, which rarely occur, one needs 56x.

Even before I asked my friend, I reasoned that if I was lucky enough to have a viewing platform to a nice beach 1.6 miles away, I would use a 120mm astro refractor or 150mm Maksutov.
I would use 75x to 125x depending on conditions.
If conditions were poor I wouldn't try for high power views.
Mornings and late afternoons are usually best.

If one insists on a binocular it should be a good powerful observation binocular.

A 25x100 low priced binocular might be useful if selected and in good alignment.
How long it would keep alignment I don't know.

The Swift 20x80 long Porroprism binoculars were used on Baywatch, but not at 1.6 miles usually.

The Zeiss 20x60S is probably the best hand held binocular for this purpose, but really not powerful enough.
Maybe A Kowa Highlander, APM or Large Vixen binocular would work.
But in the real world 1.6 miles is a big distance for dog breed identification.

On a budget, a 100mm ED Skywatcher refractor with suitable eyepieces might be sufficient.

Binastro said:

On a budget, a 100mm ED Skywatcher refractor with suitable eyepieces might be sufficient.

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Hah! I looked at that one and saw $875, and as you know by now from my other Thread, I took your advice about a telescope, but settled on the much cheaper Maksutov 127mm. I'm hoping the image through the MAK would be comparable to that obtained through the Skywatcher refractor... but if not, I can live with the savings and shorter physical length of the MAK.

DunninLA said:

Hah! I looked at that one and saw $875, and as you know by now from my other Thread, I took your advice about a telescope, but settled on the much cheaper Maksutov 127mm. I'm hoping the image through the MAK would be comparable to that obtained through the Skywatcher refractor... but if not, I can live with the savings and shorter physical length of the MAK.

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Please keep in mind that while APERTURE IS KING reflectors scatter more light than refractors and that central obstructions cause a loss of contrast. For a number of reasons, I would also choose the 127. But just thought I would throw in a reminder. :cat:

Bill

WJC said:

I would also choose the 127. :cat:

Bill

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I did. Using it with a 32mm eyepiece, and finding is incomparably better at 50x that my spotting scope, which I sold Thursday.