Binocular magnification: an immutable 2008 perspective (1 Viewer)

[Owlbarred]

With the stated advocacy by some on BF for using 12x and soon, perhaps, even 14x binoculars handheld, the following is a well known interesting counterpoint (obvious to many BF members). The excerpt, from a 2008 Audubon article on binocular magnification, is as true today as it was then. Binocular magnification No, 7x is not a panacea, but the article's fundamental postulation remains germane and is sometimes ignored on BF posts.


"My final point is that lower power binoculars provide more useful information. Remember that a binocular which magnifies an image 10 times also magnifies the small movements of your hand 10 times. Even the steadiest hands have some movement. Even if those micro-tremors aren’t obvious to you, they will make your eyes tired and you won’t know why, because your brain must work to compensate for your hand movements. A 7 power binocular will be more comfortable and less tiring to use for a full day of birding. Although this seems counter-intuitive, 7 power binoculars will give you more detail than 10s.

If you are not convinced try the following experiment. Tape a dollar bill to a wall in a sunny place with the back of the bill showing (the back is the side with the written “one” in the middle). Below the letters of the “one” there appears to be a shadow. If you look very closely you will see that the shadow is really made up of very fine lines.

Now take a pair of 10 power binoculars and mount them on a tripod and focus on the dollar bill at a distance of 10 feet. Be sure that you can distinguish the lines below the “one.” Now move the tripod back, a few feet at a time, until you can no longer distinguish the separate lines. The next step is to repeat the experiment with a pair of 7 power binoculars. You will not be surprised to find that the 10s offer superior resolution.

Now repeat the same experiment while holding the binoculars in your hand rather than mounting them on a tripod. This time the 7s will always win. It’s like a digital camera with an electronic image stabilizer. You get a much sharper image by minimizing movement.

What do I carry? My standard birding binocular is a 7x42. What did Roger Tory Peterson use while he was working on his last revision of his field guide? He used a pair of Zeiss 7x42s. Which binoculars did David Sibley use while he was working on the Sibley Guide to the Birds? You guessed it. Zeiss 7x42.

 

[Mono]

You don't need to convince we of the virtues of 7x. My three go to bins are all 7x.

 

[Swedpat]

This article is very unnuanced. Some people are more stable and definitely can make gain by 10x compared to 7x at free hand. Worth to state is that because of the magnified micro vibrations the resolution with 10x is not really 10/7x higher than 7x. But the resolution definitely is higher unless the shakings are not too strong.
Apart from that it's also about the time you use the binocular. After a few hours use your arms and shoulders become tired and this increase the hand shakings compared to from start.
An experienced binocular user is better to hold binoculars steady, it's pretty similar to an experienced shooter. So while 7x at first may be the best, after a certain period of regular practise he can increase the magnification with good result.
A good advice, though, is to choose 7 or 8x for a beginner. Ignorant users think that higher is better and choose 10, or even 12x.
Another advantage with 7x is better field of view, brightness and depth of field. So 7x is very good allround option even for an experienced user. But it is not a law that you cannot see more details with higher magnification.

 

[dorubird]

I am one of those who see more details with 10x42 than 7x42 in hands. This does not mean that 7x42 does not keep its speed in stabilization. Yes of course 7x42 bino stabilization does not require special efforts or techniques like the 10x42 one. But 10x42 bino, with a little effort in the technique, resolves more details than 7x42.
It is about my Swarovski Habicht 7x42 new version binoculars and my Zeiss Victory SF 10x42 binoculars. Both binoculars are 42mm and have similar very high performance optics. So the only thing that differentiates them in resolving the details on the center is the difference in magnification. But I must specify the fact that Zeiss SF 10x42 is not just like any 10x42, but one with phenomenal handheld stabilization. Due to the positioning of the focus wheel fixed in the center of gravity, it makes it stable during focus adjustment, more like a stable 8x42

 

[tenex]

Why do some people like to keep telling me (immutably!) why the binoculars I like to use won't work? Not even worth conversation.

 

[Owlbarred]

Why do some people like to keep telling me (immutably!) why the binoculars I like to use won't work? Not even worth conversation.

OMG. Why? Just to irritate you, though there is no challenge involved.

 

[tenex]

OMG. Why? Just to irritate you, though there is no challenge involved.

But I'll take it anyway. I happened to have an old-style dollar bill and bins of 8x, 10x, and 15x(!), and performed the hand-held portion of your esteemed author's experiment -- not with the shadowing under the letters, whose extremely fine detail requires standing closer than some of my bins focus and would make distance comparison imprecise, but the lines on the letters themselves, and other such features. The higher the magnification, the further the distance at which these lines were distinguishable. This really didn't surprise me. As a generalization for all observers, which is obviously how the author presents it, the argument above is bunk.

 

[Maljunulo]

This article is very unnuanced. Some people are more stable and definitely can make gain by 10x compared to 7x at free hand. Worth to state is that because of the magnified micro vibrations the resolution with 10x is not really 10/7x higher than 7x. But the resolution definitely is higher unless the shakings are not too strong.
Apart from that it's also about the time you use the binocular. After a few hours use your arms and shoulders become tired and this increase the hand shakings compared to from start.
An experienced binocular user is better to hold binoculars steady, it's pretty similar to an experienced shooter. So while 7x at first may be the best, after a certain period of regular practise he can increase the magnification with good result.
A good advice, though, is to choose 7 or 8x for a beginner. Ignorant users think that higher is better and choose 10, or even 12x.
Another advantage with 7x is better field of view, brightness and depth of field. So 7x is very good allround option even for an experienced user. But it is not a law that you cannot see more details with higher magnification.

The elephant in the room is the fact that some people can see better than others.

 

[Patudo]

What do I carry? My standard birding binocular is a 7x42. What did Roger Tory Peterson use while he was working on his last revision of his field guide? He used a pair of Zeiss 7x42s. Which binoculars did David Sibley use while he was working on the Sibley Guide to the Birds? You guessed it. Zeiss 7x42.

I don't for a moment question the chops of any of those birders, but other great birders have used, and still use, different formats. There's a well known photo of an incredibly well worn 10x50 porro (edit - found it! - Chandler Robbins). I always liked (though not necessarily agreeing with) Stephen Ingraham's comment from way back that 10x40s "mark a birder as a certain sort: steady handed; intently focused; experienced enough to know that he or she wants something more than the average 8 power glass; generally the type who goes boldly after the far and wee (or deep and dark) id when all about him (or her) are hedging their bets, reaching for their field guides, and bemoaning the distance and the light."

I think if you look at actual binocular sales (reflected in the models available today), even though the 7x42 format is much praised, the market has spoken - top-tier models designed for birding are hardly available. I'd guess that advancements in field of view have eroded the advantage that 7x used to have in that regard, and maybe, ergonomics (including things like the Swaro headrest) have made higher magnification binoculars steadier - I know when I tried the MHG and comparable binoculars (Meostar etc) I felt they fit my grip better than even the 10x40 Dialyt, a model I was really familiar with and always thought fitted my hands really well.

The flip side to the steadiness argument you quote is that the larger image of say a 10x can sometimes offer more information and be more satisfying. Ingraham, I think, voiced it well when he wrote: "When dealing with birds, the large image size is particularly addicting, yielding a psychological advantage that is sometimes out of proportion to the actual gain in resolution. The bird is bigger, so we think we see more detail even if we don't! Off the tripod, some of the big glasses are noticeably harder to hold steady, but for some birders added detail gained in shaky glimpses is more rewarding than a steadier but more distant view. And, of course, some of the 10x glasses are so well balanced, so finely tuned in weight and "holdability," that, in some hands at least, they provide about as steady a view as anything you could carry."

Ultimately we all agree that fieldcraft and knowledge count for more than kit. There have been plenty of times I found myself (thanks to space/weight constraints, such as when travelling) using a lower magnification than I'd have liked and was still able to both be effective and enjoy the experience. That said, for my own birding, I know I need (or at least really want) the reach sometimes. I use 10x by far the most despite also owning 7x, 8x and 12x.

 

[Thotmosis]

With the stated advocacy by some on BF for using 12x and soon, perhaps, even 14x binoculars handheld, the following is a well known interesting counterpoint (obvious to many BF members). The excerpt, from a 2008 Audubon article on binocular magnification, is as true today as it was then. Binocular magnification No, 7x is not a panacea, but the article's fundamental postulation remains germane and is sometimes ignored on BF posts.


"My final point is that lower power binoculars provide more useful information. Remember that a binocular which magnifies an image 10 times also magnifies the small movements of your hand 10 times. Even the steadiest hands have some movement. Even if those micro-tremors aren’t obvious to you, they will make your eyes tired and you won’t know why, because your brain must work to compensate for your hand movements. A 7 power binocular will be more comfortable and less tiring to use for a full day of birding. Although this seems counter-intuitive, 7 power binoculars will give you more detail than 10s.

If you are not convinced try the following experiment. Tape a dollar bill to a wall in a sunny place with the back of the bill showing (the back is the side with the written “one” in the middle). Below the letters of the “one” there appears to be a shadow. If you look very closely you will see that the shadow is really made up of very fine lines.

Now take a pair of 10 power binoculars and mount them on a tripod and focus on the dollar bill at a distance of 10 feet. Be sure that you can distinguish the lines below the “one.” Now move the tripod back, a few feet at a time, until you can no longer distinguish the separate lines. The next step is to repeat the experiment with a pair of 7 power binoculars. You will not be surprised to find that the 10s offer superior resolution.

Now repeat the same experiment while holding the binoculars in your hand rather than mounting them on a tripod. This time the 7s will always win. It’s like a digital camera with an electronic image stabilizer. You get a much sharper image by minimizing movement.

What do I carry? My standard birding binocular is a 7x42. What did Roger Tory Peterson use while he was working on his last revision of his field guide? He used a pair of Zeiss 7x42s. Which binoculars did David Sibley use while he was working on the Sibley Guide to the Birds? You guessed it. Zeiss 7x42.

How many 7’s do you own? In your signature i only see 8’s. Practice what you preach!

 

[Ignatius]

The market speaks only because it is not full of birders or other binocular afficionadoes, but replete with average Joes (and Janes) who buy what is recommended to them by the salesman/marketing teams/other Joes and Janes/has the coolest numbers/is easily available.

 

[YuShan]

You cannot generalise these things. It is personal and depending on many factors, and ultimately a tradeoff.

I had a similar choice to make myself, of course, when choosing between a 8.5x and 10x. I went for the 8.5x because I found it brighter and more pleasant and relaxing to look through, so I enjoy it more, which for me is the entire point of birding/ nature watching. But I definitely could see a bit more details with the 10x when conditions are good.

In open areas like wetlands etc where you often look at things from great distance, I would probably prefer 10x. However, in woodland where it is darker, or when trying to locate a bird that is hidden in a bush, I prefer a lower magnification. So for general use it is a trade-off that can go either way depending on personal preferences and perhaps how steady your hand is.

Another consideration for me at the time was that in places like wetlands where larger magnification helps, you can always complement your binoculars with a spotting scope, which will then perform way better than 10x binoculars. So lower powered binoculars combined with a spotting scope seems a good combination. In practice though, I ended up never buying a spotting scope because I hate carrying one around, so I would almost never use it anyway. Or worse, having spent a small capital on a good scope I would feel obliged to carry it, which would negatively affect how much I enjoy my birding (my birding style involves a lot of walking).

So, I want just one can-do-it-all instrument, which is always a trade-off. I think Swarovski was clever to offer 8.5x magnification, because most people are weighing 8x vs 10x and then 8.5x seems a great compromise. Also, I find it amazing how much you can see with such an instrument. But I'm sure I would have been happy with a 10x too.

 

[Swedpat]

The market speaks only because it is not full of birders or other binocular afficionadoes, but replete with average Joes (and Janes) who buy what is recommended to them by the salesman/marketing teams/other Joes and Janes/has the coolest numbers/is easily available.

You can see that even some reputable brands offer some models who are aimed to serious users and other to ignorant people.
For example Pentax offer 10x21 pocket model. These are cheap and by a lower quality. No knowledgeable binocular user want 10x with only 2,1mm exit pupil. Pentax have better models but not with this configuration.
Some other cheap brand offers a 12x24.
No high grade model is to find with these configurations.
Ignorant users think higher power is better while knowledgeable users know it is not that simple. But experienced users can use 10, or even 12x but then with larger aperture and with high quality and they have practised a while for it.

 

[Scott98]

What do I carry? My standard birding binocular is a 7x42. What did Roger Tory Peterson use while he was working on his last revision of his field guide? He used a pair of Zeiss 7x42s. Which binoculars did David Sibley use while he was working on the Sibley Guide to the Birds? You guessed it. Zeiss 7x42.

He forgot depth of field! The other big advantage of 7x. I think almost everyone would prefer a 7x42 for forest birding. For me the higher power is worth it when the birds start to be farther away. When they're a half mile away there is no advantage of greater DOF with lower power.

It's funny, with my astronomy telescope the magnfications used range from about 25x to 350-400x. The difference between 70x and 100x would be considered negligible. You typically jump magnifcation by 50x or more to get a different view. That argues for one bino in the 7x-10x range and higher power with a spotting scope.

For me the eye placement is the real payoff of 7x though. When I pan around to follow or locate birds, the higher the magnification is, the more KB's and blacking-out occurs as you move the binos and/or move your eye within the field. I don't see that when I look around without binoculars. Interruptions like that make using binoculars feel unnatural.

When you get out with the same exact model of binocular in 7x42 and 8x42 and use both of them for a few hours, these differences become obvious. I can guess which bino I"m using from the blacking out, not from different image scale in the view. It makes me return to the 7x42's and eventually sell the 8x and 10x

 

[OrangeO]

My final point is that lower power binoculars provide more useful information. Remember that a binocular which magnifies an image 10 times also magnifies the small movements of your hand 10 times. Even the steadiest hands have some movement. Even if those micro-tremors aren’t obvious to you, they will make your eyes tired and you won’t know why, because your brain must work to compensate for your hand movements. A 7 power binocular will be more comfortable and less tiring to use for a full day of birding. Although this seems counter-intuitive, 7 power binoculars will give you more detail than 10s.

I haven't used a 7x but I have done 10x vs 8x comparisons.

It's not life or death for me but I find that with 10x the image looks quite natural and visually pleasing. Looking through 8x I always feel like I'm missing more magnification and it feels quite unsatisfying. I always wonder if my preference is due to habit. Would I feel the same way about 10x if I started using a 12x or higher? Would I get accustomed to an 8x or lower if I used them exclusively? I'll never know.

10x is shaky enough for me that I wouldn't dream of a higher magnification for handheld use, but my experiences in the field validates my 10x. I always encounter scenarios where I wish I had more than 8x and scenarios where I'm reaching the limit of my 10x but glad I have them. My friend runs 8x and occasionally for very distant subjects we trade so he can see what I'm seeing with the 10x and it makes a difference. There are also birds beyond the range of my 10x but that is nothing I could achieve handheld so I don't feel too bad about it. There are plenty of situations I can see an 8x or lower being ideal but overall the 10x works for me.

Lower weight can be a plus but with 10x, 8x, and sometimes even 7x being built on the same "platform" they often end up being the same size and weight. I wonder how much our opinions would change if field of view and exit pupil were the same. When we compare 10x, 8x, and 7x, we are talking about the category and class of binoculars so are we really talking about our preference in field of view and exit pupil that come with these binoculars?

 

[wllmspd]

A wide 7/8x bino and a scope (size depends on the situation) for me. Wide field to find stuff and the scope to get the detail. My “only one optic” is an aged pair of canon 12x stabilised binoculars, could ace the dollar bill test with one hand. There are 15/18x stabilised models, but they are much bigger and heavier. There are always times youll want more magnification or bigger objectives to see that hit longer in the twilight, satisfying all these situations results in a collection of optics and the risk you’ll bring the wrong one for the specific salutation you’re observing in….

Peter

 

[Tringa45]

How often have we read in comparisons of 8x and 10x on this forum of "the extra 2x magnification"?
Well, it's not and when one considers that the size of the bird or its distance from the observer can differ by several hundred percent, a difference in magnification of 25% seems rather trivial, particularly as an 8x binocular already affords around 600% improvement on naked eye viewing.
There are, of course, specialised applications and I know that one of the posters on this thread whose major focus(!) is observing Hobbies in flight and uses 12x. But, increased magnification involves more image shake, reduced exit pupils and viewing comfort, almost invariably reduced FoV and a disproportionate reduction in depth of field.
The arguments for hand-held magnifications above 7x or 8x then get rather thin.

John

 

[tenex]

when one considers that the size of the bird or its distance from the observer can differ by several hundred percent, a difference in magnification of 25% seems rather trivial

This is exactly why I use 15x too, or some others 12x.

...almost invariably reduced FoV and a disproportionate reduction in depth of field.
The arguments for hand-held magnifications above 7x or 8x then get rather thin.

Yes, these are the obvious trade-offs; when the typical distances are rather long, DOF is a non-issue, and one can spare some FOV in return for more magnification (at least proportionately, often better). At short range, of course lower magnification is more convenient. (Funny, I consider this a "specialized situation", not to mention that I could recognize many of these birds without bins.) But some people just seem to like this argument so much they keep on reciting their authorities, even spontaneously out of the blue as here. It's a matter of conditions, not an immutable truth.

 

[NDhunter]

I agree, not sure what immutable means, but that is why there are lots of sizes of optics available.
Take your pick and get out there and enjoy................the great outdoors.
Jerry

 

[Maljunulo]

immutable/ĭ-myoo͞′tə-bəl/

adjective​

1. Not subject or susceptible to change.
2. Not mutable; not capable or susceptible of change; unchangeable; unalterable.
   Similar: unchangeable unalterable
3. Unable to be changed without exception.

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