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The Easy View (1 Viewer)

Bill,


I think subjective focus and sharpness are a function of the optics transfer functions, contrast at various scales, false color, glare, sharpness across the field and a bunch of other factors, and also of the ability of each binocular to maintain sharpness when focused closer than infinity, which is not an obvious property.

An interesting side effect of buying binoculars, for me, has been a huge improvement in my ability to discriminate detail at a distance. My eyes got trained within a few weeks, to the point where now I see little reason to use the binoculars most of the time!

I know that as an engineer I shouldn't say such things, but usually with these high-end psychophysiological instruments - binoculars, camera optics, loudspeakers, headphones pianos, computer screens and TVs- the user feeling becomes as important to the customer-base as the tech performance and is hard to quantify.

By accident, I tested a bunch of alphas on some crows at about 500m, and had no problem focusing with any of them, static or in flight, Zeiss, Swaro or Leica.

It's quite possible that some people get something out of fiddling with the focus knob, and also that field curvature on some binoculars has something to do with it. I know that birds are always no-problem sharp on my Ultravid HD, and so is infinity, but roof lines never "snap" and drive me crazy when I try to "feel" the texture of stones and chimneys. I would be delighted on a comment about this, it's my main "official" use of my binoculars and what they do least well in fact. I can see very car and pedestrian a mile away, but the statues on cathedrals and inscriptions on monuments simply don't "pop".

Edmund


190528

Hi, Edmund:

You said, “It's quite possible that some people get something out of fiddling with the focus knob ...”

That comment was RIGHT ON!

I knew a fellow who, each time he would speak in church, would incessantly shift the microphone like a racecar driver. Once in a 12-minute talk, he moved it more than 60 times. Did his height change? It did not. Did the podium change its height? It did not. Did any of those 60+ settings alter the content of what he had to say or the volume thereof ... substantially, anyway? It did not. Obviously, the useless exercise provided some unknown something for him.

As far as “snapping” into focus, Lee has the basics of an answer for you. To push it a little farther, let’s look at those statues. From top to bottom they are made of bright and dim promontories, recesses, and flat areas, separated, sometimes by only inches. Your brain is doing the best it can to quantify things for you, but you are just being too hard on it. Looking through an “ALPHA” is not going to change the physiological realities of you not being Superman.

This is the kind of topic that can be talked about and speculated to death. My original comment concerning “staring” I KNOW to be true. I have proven it through conversations with many customers, using binoculars ranging from ALPHAS to OMEGAS. I didn’t set out to conduct scientific testing. However, over time, the database builds. I wanted so badly to become an optical engineer. But I didn’t have the mathematical sense to become one. Thus, I have had to satisfy myself with having devised some of the routines in some of the best optimization programs and knowing that when seasoned engineers flounder with the nuts and bolts of the technology, they often call on me. That most certainly is not to say that my seat-of-the-pants engineering (Zemax-EE) is on par with even the dumbest engineer out there. But when you have dealt with certain facets of the technology every day for years, you can’t escape learning something. :cat:

Bill
 
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Sorry, but no cigar, this time...
[snip, snip]
Last week, in post #4—relating to the “focus drift” thread—on Cloudy Nights (attached), I had a friend post something from my book, dealing with that very issue...
[snip, snip]
That's OK, I don't smoke.

Now I see that the problem was that you don't explain what you mean by "Focus by STARING and let the bino’s focus mechanism do its job". Once the context is provided (in that attachment) it becomes clear that you're talking about some strange problem with focusing itself that I've never had (and how many have?), which is why I missed your point and imagined that you were suggesting something else (that refocusing wasn't always necessary). Trying to preemptively correct misunderstandings that people aren't suffering from is unnecessary and can even create misunderstanding. Perhaps a simpler approach without negative preconceptions would cause less trouble, unless you actually enjoy feeling misunderstood.

Nice to have connected better on the Inland Sea, though.
 
I've experienced focus drift before, though fortunately only on only two binoculars. Some binoculars with an external focusing mechanism (like most porros have - although not all porros are susceptible to focus drift) can have the focuser move slightly if the binocular is pressed too hard against one's face. The flimsier and less precisely built the bridge assembly is, the more likely it is to happen. A well-made binocular can sometimes be put right by a competent technician (as I've seen with a 7x42 Dialyt that had a minor case of focus drift); but if the binocular in question is less well designed or built, as the PRC-made 15x70 in the Cloudynights thread may be, the issue may be much harder to remedy.

...let's say you have an accommodation range of 4 diopters and stop focusing the instant you have an adequate image. As time goes on, observing may become problematic because your natural (relaxed at that distance) focus setting should be -1.5 diopters. That means being in a hurry has placed your focus at an accommodatable, but strained, setting.

With regard to the passage above... if you find yourself in the situation described, you can STARE all you wish, and try to make the image you're seeing improve itself by force of will, or you can move - fiddle with, if you want to call it that - the focus wheel and tweak it to perfect sharpness. With today's fast focusers only a very tiny adjustment may be required - I actually prefer a slower focuser for what I do because it gives more leeway.

Ease of view - as others have mentioned, larger exit pupil helps, and for me, the so-called field flatteners also help, making for easier eye placement and reducing fatigue when observing for long periods. I think a large field of view can help, but some of my porros with large fields of view are also on the fiddly side. Viewing conditions can make a huge difference too - most binoculars are easy to use on a nice sunny day. As far as specific models I've tried are concerned, the 10x50 WX had the most fantastically fatigue-free, effortless view I've ever seen, but requires your elbows to be well braced, or ideally mounted on a tripod. The lower magnification of an 8x makes for an easier view in itself (hence the praise on this thread for 7x42). I don't, alas, have extensive experience of as many quality 8x class binoculars as I'd like to, but I have a goodly number of hours behind a 8.5x42 Swarovski field pro and that most certainly offers an effortless, as well as superbly sharp and detailed view. I have also briefly tried the 8x56 SLC which was large and bulky but outstandingly good in all respects including ease of view.
 
That's OK, I don't smoke.

Now I see that the problem was that you don't explain what you mean by "Focus by STARING and let the bino’s focus mechanism do its job". Once the context is provided (in that attachment) it becomes clear that you're talking about some strange problem with focusing itself that I've never had (and how many have?), which is why I missed your point and imagined that you were suggesting something else (that refocusing wasn't always necessary). Trying to preemptively correct misunderstandings that people aren't suffering from is unnecessary and can even create misunderstanding. Perhaps a simpler approach without negative preconceptions would cause less trouble, unless you actually enjoy feeling misunderstood.

Nice to have connected better on the Inland Sea, though.

Hi, Tenex

It was a figure of speech; I have never smoked, either. I don’t even like the word “cigarette.”

I’m glad you don’t have problems with “focus drift.” But I can assure you that far more than you realize ... DO! And that’s why the comment was appropriate. So many suffer unnecessarily with the problem because they have convinced themselves, (like the non-reading CN member) “it’s the eyes,” when, in fact, it IS NOT! But although you can’t save some people from themselves, I do try. Having cared about the science and working everyday with repair and retail customers gives one a perspective not shared with the average bino user. :cat:

Bill
 
I've experienced focus drift before, though fortunately only on only two binoculars. Some binoculars with an external focusing mechanism (like most porros have - although not all porros are susceptible to focus drift) can have the focuser move slightly if the binocular is pressed too hard against one's face. The flimsier and less precisely built the bridge assembly is, the more likely it is to happen. A well-made binocular can sometimes be put right by a competent technician (as I've seen with a 7x42 Dialyt that had a minor case of focus drift); but if the binocular in question is less well designed or built, as the PRC-made 15x70 in the Cloudynights thread may be, the issue may be much harder to remedy.



With regard to the passage above... if you find yourself in the situation described, you can STARE all you wish, and try to make the image you're seeing improve itself by force of will, or you can move - fiddle with, if you want to call it that - the focus wheel and tweak it to perfect sharpness. With today's fast focusers only a very tiny adjustment may be required - I actually prefer a slower focuser for what I do because it gives more leeway.

Ease of view - as others have mentioned, larger exit pupil helps, and for me, the so-called field flatteners also help, making for easier eye placement and reducing fatigue when observing for long periods. I think a large field of view can help, but some of my porros with large fields of view are also on the fiddly side. Viewing conditions can make a huge difference too - most binoculars are easy to use on a nice sunny day. As far as specific models I've tried are concerned, the 10x50 WX had the most fantastically fatigue-free, effortless view I've ever seen, but requires your elbows to be well braced, or ideally mounted on a tripod. The lower magnification of an 8x makes for an easier view in itself (hence the praise on this thread for 7x42). I don't, alas, have extensive experience of as many quality 8x class binoculars as I'd like to, but I have a goodly number of hours behind a 8.5x42 Swarovski field pro and that most certainly offers an effortless, as well as superbly sharp and detailed view. I have also briefly tried the 8x56 SLC which was large and bulky but outstandingly good in all respects including ease of view.

Hi, Patudo:

You, too, missed the point. You are speaking of a mechanical “Focus Drift,” not the more common physiological “focus drift.” I have covered the mechanical version at length. One of the attached is a snippet from my first bino book and the second is a graphic from one of my monographs.

Tenex has pointed out that I may not have explained adequately in my forum post. I can accept that. But please understand, that sometimes pages could be offered on a simple topic and there would be those who still didn’t get it. And if I offered enough information for people of all persuasions and levels of understanding to “get it,” you may rest assured I would be viewed as verbose, arrogant, condescending, and worse. ‘Been there; done that; have the tee shirt. Sometimes, a guy can't win for losing.

Wasn’t it Aristotle who said, “Confidence is often seen as arrogance when viewed from below.”

In the particular instance above, I am not speaking of Aristotle P. Snodgrass from Bugtussle, Kentucky but that real old Greek feller. :cat:

Bill
 

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Hi, Tenex

It was a figure of speech; I have never smoked, either. I don’t even like the word “cigarette.”

I’m glad you don’t have problems with “focus drift.” But I can assure you that far more than you realize ... DO! And that’s why the comment was appropriate. So many suffer unnecessarily with the problem because they have convinced themselves, (like the non-reading CN member) “it’s the eyes,” when, in fact, it IS NOT! But although you can’t save some people from themselves, I do try. Having cared about the science and working everyday with repair and retail customers gives one a perspective not shared with the average bino user. :cat:

Bill

I think that Bill is both right and not right. I was watching gulls this weekend whenever I saw them, on vacation. Most of the time, I could pick up the binos frpm the table, no focus necessary, keep the finger away from that knob, enjoy the view. But for scenery near infinity tiny adjustments really help, and the same goes for the gull perched 20 yards away.

Edmund
 
I think that Bill is both right and not right. I was watching gulls this weekend whenever I saw them, on vacation. Most of the time, I could pick up the binos frpm the table, no focus necessary, keep the finger away from that knob, enjoy the view. But for scenery near infinity tiny adjustments really help, and the same goes for the gull perched 20 yards away.

Edmund

That means your spatial accommodation focussed your eye lens for you. That is how Steiner made a bazillion dollars ... convincing people who were easily convinced that what was impossible was commonplace in THEIR binoculars. The verbal explanation in post 45 explains it all. :cat:

Bill
 
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Easy view, preferred format, most used...some interesting threads here lately.
The easiest view may be my preferred format, but it is not my most used, because of ergonomic tolerance.


Eventually failing strength and worsening arthritis will mean I'll be squinting and using an 8x30 porro ;)
 
That means your spatial accommodation focussed your eye lens for you. That is how Steiner made a bazillion dollars ... convincing people who were easily convinced that what was impossible was commonplace in THEIR binoculars. The verbal explanation in post 45 explains it all. :cat:

Bill

Yes, yes, you are undoubtedly right. But the $$$$ question is how much an optical design can compress the depth of field to where eye accomodation can then allow one to view stuff sharply.

It's not obvious that the depth of field is the same for all binos.

Edmund
 
Yes, yes, you are undoubtedly right. But the $$$$ question is how much an optical design can compress the depth of field to where eye accomodation can then allow one to view stuff sharply.

It's not obvious that the depth of field is the same for all binos.

Edmund



I think it is the same for all 6x's; all 7x's; all 8x's, all 10x's and on up the line.

Bob
 
I think it is the same for all 6x's; all 7x's; all 8x's, all 10x's and on up the line.

Bob

Eronald:

Not only is ceasar as correct as he is succinct, but I would also suggest you read the article found at:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4461356/

It is part of an all-inclusive article by the US National Library of Medicine, published Oct. 2014 and I have attached the abstract. After reading the article, you will see why I have such fun talking about all the “BB stacking” that takes place on binocular forums. You will undoubtedly find the last sentence of the “conclusion” most interesting. :cat:

Bill
 

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The problem with roofs is focus asychronicity, aka focus slop.i have two roofs that don't focus both directions, only one way.Swaro fixed this with a spring, but folks didn't like that. I guess.
 
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I think it is the same for all 6x's; all 7x's; all 8x's, all 10x's and on up the line.

Bob


In telephotos, mathematical depth of field depends on objective lens aperture and focal length. Subjective front and back depth of field, bokeh, and subjective separation depend on the actual lens design. This every photographer knows.

For binoculars, one could assume that dof will diminish with magnification and increase with smaller objective sizes. Thus an 8x20 could be expected to have much more dof than a 10x50 and won't demand much focusing near infinity, but also the 10x50 will pick a bird better out of the clutter of a tree-line :)

Also both sides of a bino can probably be focused slighly apart, the faulty setting actually increasing the subjective dof :) It might make sense to voluntarily mis-set the diopter slightly.

Edmund
 
In telephotos, mathematical depth of field depends on objective lens aperture and focal length. Subjective front and back depth of field, bokeh, and subjective separation depend on the actual lens design. This every photographer knows.

For binoculars, one could assume that dof will diminish with magnification and increase with smaller objective sizes. Thus an 8x20 could be expected to have much more dof than a 10x50 and won't demand much focusing near infinity, but also the 10x50 will pick a bird better out of the clutter of a tree-line :)

Excellent observation. My impression is that magnification has a greater effect on DOF in binos than objective size, but it seems complicated because that isn't the same as aperture or speed ("f/?"). Does aperture in this sense vary much among binos?
 
In telephotos, mathematical depth of field depends on objective lens aperture and focal length. Subjective front and back depth of field, bokeh, and subjective separation depend on the actual lens design. This every photographer knows.

For binoculars, one could assume that dof will diminish with magnification and increase with smaller objective sizes. Thus an 8x20 could be expected to have much more dof than a 10x50 and won't demand much focusing near infinity, but also the 10x50 will pick a bird better out of the clutter of a tree-line :)...

To anyone interested in this topic, I recommend spending a day doing searches and reading from the archives of BirdForum. Much discussion of these topics suffers from misapplication of intuitions/assumptions that come from experience with camera lenses. Nevertheless, the topic of DOF in bins and scopes has been discussed in great and accurate detail here on BirdForum, including theoretically/mathematically, and through practical/experimental demonstrations. Long story short, binocular DOF is determined by magnification alone, not aperture or length or other factors. Magnification aside, the biggest variation in user experiences comes from how much eye accommodation users have, and perhaps, occasionally in some low light levels, how much their pupils open.

--AP
 
In telephotos, mathematical depth of field depends on objective lens aperture and focal length. Subjective front and back depth of field, bokeh, and subjective separation depend on the actual lens design. This every photographer knows.

For binoculars, one could assume that dof will diminish with magnification and increase with smaller objective sizes. Thus an 8x20 could be expected to have much more dof than a 10x50 and won't demand much focusing near infinity, but also the 10x50 will pick a bird better out of the clutter of a tree-line :)

Also both sides of a bino can probably be focused slighly apart, the faulty setting actually increasing the subjective dof :) It might make sense to voluntarily mis-set the diopter slightly.

Edmund


The brain rarely works on mathematical principles and the workings of the physiological principles differ from person to person. I know people get tired of me talking about the physiological. However, as long as people try to skirt its realities, I will keep bringing it up. I thought that scientific/medical abstract would do the trick. Apparently not.

I know most want concrete—one size fits all—answers. Yet, those of us destined to live in the real world know that’s not a happening thing and it is never going to be.

The optical submarine periscope is being replaced by the electronic “photon mast.” Perhaps we could have eyes replaced by photonic sensors. That way things could be a LITTLE more quantifiable. But then, people would argue about who had the latest “Alpha” sensors.

Funny? Perhaps. Off the wall? Oh, yeah. Accurate? The track record says undoubtedly so.

Bill
 
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Hi, Patudo:

You, too, missed the point. You are speaking of a mechanical “Focus Drift,” not the more common physiological “focus drift.” I have covered the mechanical version at length. One of the attached is a snippet from my first bino book and the second is a graphic from one of my monographs.

The section of text from your attachment in your post #37 I commented upon relates to physiological, not mechanical focus drift. I quoted it in my post (#43) to make sure that was fully understood. Here it is again:

However, let's say you have an accommodation range of 4 diopters and stop focusing the instant you have an adequate image. As time goes on, observing may become problematic because your natural (relaxed at that distance) focus setting should be -1.5 diopters. That means being in a hurry has placed your focus at an accommodatable, but strained, setting.

Now, if the above discusses mechanical rather than physiological focus drift, please let us know. (Funnily enough, the Cloudynights thread you requested your friend respond to with the above extract would seem to be an example of mechanical focus drift in the original poster's 15x70mm binocular, as he has no such issues with his other binoculars.) But, in any case, if observation is problematic or strained, should one STARE, and hope the image will improve by itself - or move that focus wheel, and do something about it?

I myself certainly experience physiological focus drift of a sort, in that my favourite spot is a fifteen minute walk from the bus stop and up six or seven storeys. That's nothing compared to the distances many of you travel, of course, but enough that after finding my target on (hopefully) my first look around the area, I'll have to tweak the focus to achieve the most effortless possible view as I cool off. I need to keep my target, normally 550m or more away, under observation until it flies, which could be as soon as five minutes but which might take a quarter of an hour or more. It's important that the image be as "easy", effortless, call it what you will, as possible while doing so, and to achieve that, I need to adjust the focus wheel - normally not by very much, nor very often, but some fine-tuning is almost always necessary. Granted, when using a 7x less fine tuning is required than with 8x or 10x because of the greater depth of field. But I really prefer to use one of the latter two when looking at pigeon-sized targets that distance away...

I use my accommodation when I have to - when the bird has taken off in hot pursuit and things are happening too fast to refocus. But for the much longer periods of waiting and watching, why on earth should one have to accommodate - when a tweak of the focus wheel can deliver a more relaxed view? :cat:
 
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The section of text from your attachment in your post #37 I commented upon relates to physiological, not mechanical focus drift. I quoted it in my post (#43) to make sure that was fully understood. Here it is again:



Now, if the above discusses mechanical rather than physiological focus drift, please let us know. (Funnily enough, the Cloudynights thread you requested your friend respond to with the above extract would seem to be an example of mechanical focus drift in the original poster's 15x70mm binocular, as he has no such issues with his other binoculars.) But, in any case, if observation is problematic or strained, should one STARE, and hope the image will improve by itself - or move that focus wheel, and do something about it?

I myself certainly experience physiological focus drift of a sort, in that my favourite spot is a fifteen minute walk from the bus stop and up six or seven storeys. That's nothing compared to the distances many of you travel, of course, but enough that after finding my target on (hopefully) my first look around the area, I'll have to tweak the focus to achieve the most effortless possible view as I cool off. I need to keep my target, normally 550m or more away, under observation until it flies, which could be as soon as five minutes but which might take a quarter of an hour or more. It's important that the image be as "easy", effortless, call it what you will, as possible while doing so, and to achieve that, I need to adjust the focus wheel - normally not by very much, nor very often, but some fine-tuning is almost always necessary. Granted, when using a 7x less fine tuning is required than with 8x or 10x because of the greater depth of field. But I really prefer to use one of the latter two when looking at pigeon-sized targets that distance away...

I use my accommodation when I have to - when the bird has taken off in hot pursuit and things are happening too fast to refocus. But for the much longer periods of waiting and watching, why on earth should one have to accommodate - when a tweak of the focus wheel can deliver a more relaxed view? :cat:

It is definitely about physiological.

“But, in any case, if observation is problematic or strained, should one STARE, and hope the image will improve by itself ...”

I said nothing even resembling that! You don't HOPE for anything.

Although I have beaten this dead horse ... to death, I will try, again.

If you learn to stare and be doing so while you are turning the focus knob, you will arrive at a RELAXED focus for that particular distance.

If you don’t do that, if you think it’s irrelevant, or think your opinion supersedes the realities of the matter, you will spend an inordinate amount of time fiddling with the focus. One over, one under, one on is appropriate for artillery ... not so good for optics.

Finally, he shouldn’t have to accommodate!!! That’s what I have spent a few hundred words trying to explain. If you don’t focus correctly, you must use accommodation. To focus correctly means to learn to stare and let the focus mechanism do its job. Although I want to be helpful, I have chased my tail long enough to see I’m not making any headway. Although I’m an old dog, I still haven’t learned I need not chase ever car that passes. :eek!:

Bill
 
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Threads a little dated but just found it. I’ve come to the conclusion that dof is one of the most important virtues in a binocular, for me anyway. I translate an easy view as being lifelike and natural, as close as possibly to performing as the naked eye.

I’ve noticed when I hand 9 out of 10 people, especially the inexperienced, a binocular such as a Leica 7x42, a swaro slc 8x50/56, even the original 98-2000 Nikon venturer, they almost immediately say it’s better than say the same manufacture in a 10x or even many 8’s. It’s a natural reaction, a relief of sorts to have a lifelike view as close as possible to what we see unmagnified.

I understand why many like a shallow dof, especially viewing small objects and when pinpoint accuracy is needed, but for me a relaxing bin with a great dof, all being equal quality of course, gets used more.

It’s really to bad Leica, swaro, and Zeiss hasn’t put r@d to make a modern 7x with a large apparent fov. I feel like a Leica/swaro 7x42 with a 64 to 70 apparent fov combined with their already great natural image would be the most useable and wow factor binoculars made.
 
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