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How much of x10 (over x8) is psychological?

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Old Saturday 19th January 2019, 09:11   #26
StephenHampshire
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Originally Posted by elkcub View Post
All,

This discussion might benefit from the attached article by Daniel Vukobratovich (1989), who co-authored SPIE's more recent "Field Guide to Binoculars and Scopes." Fig. 1 and Table 1 pretty much tell the story without having to ponder the main equation. Basically, hand-held detection efficiency approaches a calculated upper limit, or plateau, at a magnification of about 10. Of course, that doesn't take other performance factors into account such as FOV, ER, weight, size, and balance. The article is amazingly comprehensive.

Ed
Thank you, as a relative newcomer to "proper" binoculars, that article is a good primer
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Old Saturday 19th January 2019, 19:46   #27
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There are targets just too far away for a 10x but which a 12x would reveal, while targets even further away are only accessible by 15x.
This. At one of the best viewpoints I go to the nest building is some 1.7km away and the birds will range much further. I normally use 10x there as I have had them go out of range of 8x often enough that the extra mag is needed more than the field of view of an 8x. There is a time of year (coming soon) that even 12x is justified but I use the 12x I have quite reluctantly because its field of view (96m, from memory) begins to feel limiting.
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Old Saturday 19th January 2019, 20:42   #28
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Years ago, I put great effort in analysing this topic. I used to think of 8x as a bad compromise, and advocated a 10x32 combined with a 6.5x32.
I found my previous 8x33 lack in depth of field compared to 6.5x, while still being not as binary sharp/fuzzy as a 10x. That was then, and then I got myself an E II 8x30. With supported elbows, I compared it to my FL 10x32 and found there's exactly nothing visible with the 10x not visible with the 8x, and I'm talking about small details over 2 km distance. As a result, I sold all my 10x.

---

The linear magnification of a 10x is 25% greater than that of an 8x, however the image area of an object (bird) is 56% greater.
The impression is undeniably massive, but given the other disadvantages, I hardly see the 10x as a jack-of-all-trades. Over really long distance, I have found that a 12x often can replace a 30x scope. Not so with a 10x.

Compared to an 8x binocular, the 12x greatly emphasises the background. The foreground can often be covered with less magnification if you can access the area by foot, but the background requires considerably longer walks, obviously impossible to undertake if it's the sea or a lake.

So 8x is the baseline/allround binoculars for me,and the 12x serves a completely different purpose, where it is markedly different from the 8x, and, for that particular purpose, superior to a 10x.

I live close to the sea, and if the coastline was all my birdwatching, and if I could only own one binocular, maybe it should be a 10x42 or 10x50. But the compact 8x32, the powerful 12x50 and the very bright 7x42 cover everything I could possibly encounter. If I lived in the inland, maybe an 8x42 would be the closest to an allround binocular I could ever get.

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Old Saturday 19th January 2019, 22:33   #29
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Skill, ability, experience will trump a 20% mag. increase every time.
Agree fully with this.

Worry less about magnification and focus on being a better birder.
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Old Sunday 20th January 2019, 11:52   #30
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On a visit to Keyhaven Marshes that was quite right.

Until the leader of the group had spotted the first one, we could not see a Dartford Warbler anywhere - he had looked for an easier Stonechat as a marker, and also knew just just where in the bushes to look.

I had both Nikon SEs 8x and 10x along at the time, in order to determine which was best for such expeditions. In the end I could not say which showed the best detail but ease of use came into it so I picked the 8x32.

However the view with 10x was more satisfying and I'm certain such 'personal' impressions might just as well be called 'psychological'!
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Old Sunday 20th January 2019, 14:12   #31
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Both 8X and 10X have their uses, and not just for the ID of a bird. Perhaps most can hold an 8X steady, and fewer can hold 10X -12X steady.

Andy W.
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Old Sunday 20th January 2019, 16:33   #32
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All I know is....when I go to the coast, or in any other open area, and many times during winter, I use 10X or even 12X binoculars. Why? Because I believe the increased magnification helps me to ID birds. Is there a lot of difference? No. BUT I do believe in using the best instrument for the job and 10X/12X is the better instrument for the job in some situations.
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Old Sunday 20th January 2019, 18:20   #33
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Agree fully with this.

Worry less about magnification and focus on being a better birder.

Yep, getting good at understanding and interpreting GIS on distant birds will result in needing less mag. for an ID.

I switched to an 8 a few years ago, after 30 years with 10's and have never had occasion to think that I can't make an ID due to losing that mag. Distant raptors are ID'ed on GIS [overall shape, flight style, wing loading etc] not field marks per se. Same applies to most groups - waders present distinctive profiles and feeding actions and postures, far more useful than trying to look for tertial patterns, which you really need a mounted scope for anyway.

Even when looking for fieldmarks on distant waterfowl for instance - like the white shoulder crescent on a Ring-necked Duck or the throat pattern of a Merganser, an 8 provides [me] with a better [more stable, more observable], albiet slightly smaller, view of such marks.
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Old Sunday 20th January 2019, 19:32   #34
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One other thing in this regard that cannot be ignored here is field of view, most importantly apparent field of view. Chris 6 illustrates this in post 23. I have started to develop the thought that AFOV is actually a bigger draw to 10x than the extra magnification. A 6.5* angular fov plants a 10x in the typically acceptable wide angle view definition. Obviously it takes 8* to do that with an 8x. Wider fields it seems have more aberrations to deal with than smaller ones. With the smaller, yet apparently as wide 10x fov, the image both looks closer. larger, and there is less distractions around the target bird, and our eyes wander somewhat less. How different eyes react to this is largely due, I think, to psychology as well as to technology. The wide angle view folks may well take issue here, so feel free to disagree. My preference is 8x with an 8* angular fov.
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Old Sunday 20th January 2019, 20:26   #35
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One other thing in this regard that cannot be ignored here is field of view, most importantly apparent field of view. Chris 6 illustrates this in post 23. I have started to develop the thought that AFOV is actually a bigger draw to 10x than the extra magnification. A 6.5* angular fov plants a 10x in the typically acceptable wide angle view definition. Obviously it takes 8* to do that with an 8x. Wider fields it seems have more aberrations to deal with than smaller ones. With the smaller, yet apparently as wide 10x fov, the image both looks closer. larger, and there is less distractions around the target bird, and our eyes wander somewhat less. How different eyes react to this is largely due, I think, to psychology as well as to technology. The wide angle view folks may well take issue here, so feel free to disagree. My preference is 8x with an 8* angular fov.
I use a 10x32 for watching birds in my garden. My prime interest is in observing there behaviour, ID is not normally a problem. I do find I enjoy the view more with a 10x than with my 8x bins, narrower FoV concentrates the view on the subject. Locating a bird is less of an issue as they tend to concentrate round the feeders etc so I know the areas I need to look at. I am sure that magnification plays a role alongside the FoV- in photographic terms I would call this increased subject isolation.
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Old Sunday 20th January 2019, 21:05   #36
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This discussion might benefit from the attached article by Daniel Vukobratovich (1989)...Basically, hand-held detection efficiency approaches a calculated upper limit, or plateau, at a magnification of about 10.
Interesting article, thanks. Note however that he defines "detection" in terms of whether you can detect a distant target at all, not identifying subtle details (like color) in your view of it. Are these quite the same thing?

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One other thing in this regard that cannot be ignored here is field of view, most importantly apparent field of view. Chris 6 illustrates this in post 23. I have started to develop the thought that AFOV is actually a bigger draw to 10x than the extra magnification.
I agree that larger AFOV is a significant part of the attraction of 10x to me, and the first thing I miss when I pick up an 8x bino. This is more an aesthetic preference than a matter of practical results, but enjoyment counts too.
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Old Sunday 20th January 2019, 21:33   #37
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I've been woefully inadequately equipped with optics recently, but this leads to an interesting obervation perhaps - with cheaper bins 8x may be better than 10x?

Went into an optics shop last week to purchase some reasonably priced optics for the partner (and by default, myself as I will likely use them more ) - looking at the Opticron Oregon 110 - 130 price range.

The much brighter image of the 8x far outweighed any advantage the 10x (in the same range) gave looking at a Herring Gull on a nearby roof - no contest.
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Old Sunday 20th January 2019, 22:50   #38
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Hi Lars,
Post 28.

Have you heard the one 'Alpaca walks into opticians shop'?

I just saw this on the BBC that claimed it spent half an hour perusing the lenses.

Off topic I know, but maybe it needed glasses. (:

In Brittany, France.

B.

P.S.
I use all magnification binoculars from 2x to 30x.
I brace the higher magnification ones well.
My normal binoculars used to be 10x50, 12x45 and 12x50.
I had no trouble hand holding 20x60 and 20x80 binoculars, either free handed or braced. The weight and bulk steadied them.
The balance and fit of a binocular is very important.

Even though the Canon 10x30 Mk2 IS has better stabilisation than the Canon 18x50 IS, the extra weight and inertia of the 18x50 gives it the steadier view.
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Old Sunday 20th January 2019, 23:24   #39
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Interesting article, thanks. Note however that he defines "detection" in terms of whether you can detect a distant target at all, not identifying subtle details (like color) in your view of it. Are these quite the same thing?
...
Hi Tenex,

As stated in the article, Vukobratovich relied on Kohler and Leinhos' definition of range efficiency based on visual acuity, which incidentally was measured using Landolt C rings as opposed to the more popular grating acuity, but neither acuity method addresses the effect of color. So binocular range "efficiency" is simply an effort to express how much visual acuity is recovered using a binocular compared to the naked eyes. The approach does have technical limitations but the relative effectiveness of increasing magnification under handheld daylight viewing conditions is pretty evident. Basically, it's just the familiar case of diminishing returns.

Ed
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Old Sunday 20th January 2019, 23:34   #40
dantheman
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Have you heard the one 'Alpaca walks into opticians shop'?

I just saw this on the BBC that claimed it spent half an hour perusing the lenses.

Off topic I know, but maybe it needed glasses. (:
As jokes go, I've not heard llama.


;-)
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