oldfortyfiveauto
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The BirdForum is outstanding. I've been following it for a while and have learned a lot, especially about aging eyes.
CHEAP Hi end Binoculars
- Thread starter saenzrich
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taliv, I'm definitely interested in image stabilization at some point but that technology doesn't come cheap. Image stabilization with a built in range finder and some form of angle compensation would be awesome, particularly if the weight can be kept under 25oz.
buckhorn_cortez
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One of the things you can do in evaluating binoculars is to look at the exit pupil diameter. The maximum it can be is the diameter of the front lens divided by the magnification.
Most binoculars will be less than the calculated number because of the design of the optical system. The closer it is to the maximum number - the better because it gives an image with less edge cutoff and more light transmission.
This is important because it relates to the human eye. The eye's maximum pupil diameter is 8mm. As we age, the maximum gets less because of stiffening of the eye and loss of muscle tone in the eye causing the pupil's maximum opening to decrease.
However, the larger the exit pupil, the more light will be transmitted to the retina. As an example, the maximum exit pupil for an 8x42 binocular is 5.25, while the exit pupil on a 7x50 binocular will be 7.14. As can be seen by the simple math, the 7x50 will transmit approximately 23% more light - making a brighter image in lower light.
Related to this, but not nearly as important as it once was is a measurement called "twilight factor." This is an optical calculation giving a measurement of performance in dim light. Twilight factor = square root (magnification x front objective diameter). It is really no longer applicable as lens multi-coatings can double the amount of light transmitted.
Another metric that should be published by the manufacturer is the percentage of light transmission. One hundred percent would be perfect, and the maximum. However, no optical system is perfect because of internal light losses. Today, because of multi-coating and better glass the transmission should be above 94% for most binoculars.
Another thing that is not talked about is contrast. Unfortunately, most binocular manufacturers will not give a contrast measurement, but optics with higher contrast appear sharper because the human optical system is biased towards contrast differences. You have to look through the binoculars and evaluate the contrast yourself.
You can do that by looking at an object with bright and dark areas and making a mental note as to how much darker (or blacker) the dark area looks in comparison to another binocular. The greyer (or lighter) the dark area looks, the less contrast the binoculars have, and in use, the less sharp the overall image will look.
This has to do with an optical measurement called modulation transfer function (MTF) that gives the absolute measurement of optical sharpness, but has the ability to show a difference in contrast if you know how to read the MTF graph. Lower contrast makes the square waves generated by the black / white line pairs shallower and degrades the appearance of sharpness by lessening the differentiation between the line pairs. It does this because the line pairs no longer look like individual black and white lines, as they merge together and look grey.
The Germans (mainly Leica) will tradeoff absolute MTF resolution performance in their optics for better contrast because they understand the human eye will perceive greater sharpness because of greater contrast.
Another thing to look for is chromatic aberrations which will show up as fringing (colors at edges) when looking at a high contrast area. Well designed binoculars will be APO chromatic, meaning all of the colors will be focused at the same point - and you won't see fringing.
This is the main benefit of HD or ED glass (generally fluorite lens elements) as the give the optical designer the ability to engineer the same amount of refraction (light bending) without chromatic aberrations.
Lastly, you should look at the features and mechanical construction of the binoculars. Larger center hinges mean a more robust mechanical design. Other features can include individual diopter adjustment for both left and right sides.
The Leica binoculars have a feature that sets them apart in this area. They have two separate, independent center wheel adjustments for left and right diopters. Once you individually set the diopter correction for each eye - you "snap" the adjustment wheels together by pushing the top wheel down allowing you to focus both sides simultaneously to focus the binoculars.
Another thing you can look for is how the binocular creates an eyecup. Is the eyecup simply a rubber piece that can be folded over, or is it done as a built-in, retractable eyecup that can be set at an optimum distance for the user by screwing or pulling the built-in cup up or down.
A final feature that may make a difference to some users is the coatings on the eyepiece and objective lenses. Expensive binoculars will have "nano coatings" that give both abrasion resistance and water shedding ability so that droplets aren't formed on the lenses' surface and viewing remains relatively clear in fog, mist, and rain conditions.
Unfortunately, if you're buying binoculars over the Internet, you don't have the ability to handle the binoculars and make your own evaluation of the optics and mechanical build.
Most binoculars will be less than the calculated number because of the design of the optical system. The closer it is to the maximum number - the better because it gives an image with less edge cutoff and more light transmission.
This is important because it relates to the human eye. The eye's maximum pupil diameter is 8mm. As we age, the maximum gets less because of stiffening of the eye and loss of muscle tone in the eye causing the pupil's maximum opening to decrease.
However, the larger the exit pupil, the more light will be transmitted to the retina. As an example, the maximum exit pupil for an 8x42 binocular is 5.25, while the exit pupil on a 7x50 binocular will be 7.14. As can be seen by the simple math, the 7x50 will transmit approximately 23% more light - making a brighter image in lower light.
Related to this, but not nearly as important as it once was is a measurement called "twilight factor." This is an optical calculation giving a measurement of performance in dim light. Twilight factor = square root (magnification x front objective diameter). It is really no longer applicable as lens multi-coatings can double the amount of light transmitted.
Another metric that should be published by the manufacturer is the percentage of light transmission. One hundred percent would be perfect, and the maximum. However, no optical system is perfect because of internal light losses. Today, because of multi-coating and better glass the transmission should be above 94% for most binoculars.
Another thing that is not talked about is contrast. Unfortunately, most binocular manufacturers will not give a contrast measurement, but optics with higher contrast appear sharper because the human optical system is biased towards contrast differences. You have to look through the binoculars and evaluate the contrast yourself.
You can do that by looking at an object with bright and dark areas and making a mental note as to how much darker (or blacker) the dark area looks in comparison to another binocular. The greyer (or lighter) the dark area looks, the less contrast the binoculars have, and in use, the less sharp the overall image will look.
This has to do with an optical measurement called modulation transfer function (MTF) that gives the absolute measurement of optical sharpness, but has the ability to show a difference in contrast if you know how to read the MTF graph. Lower contrast makes the square waves generated by the black / white line pairs shallower and degrades the appearance of sharpness by lessening the differentiation between the line pairs. It does this because the line pairs no longer look like individual black and white lines, as they merge together and look grey.
The Germans (mainly Leica) will tradeoff absolute MTF resolution performance in their optics for better contrast because they understand the human eye will perceive greater sharpness because of greater contrast.
Another thing to look for is chromatic aberrations which will show up as fringing (colors at edges) when looking at a high contrast area. Well designed binoculars will be APO chromatic, meaning all of the colors will be focused at the same point - and you won't see fringing.
This is the main benefit of HD or ED glass (generally fluorite lens elements) as the give the optical designer the ability to engineer the same amount of refraction (light bending) without chromatic aberrations.
Lastly, you should look at the features and mechanical construction of the binoculars. Larger center hinges mean a more robust mechanical design. Other features can include individual diopter adjustment for both left and right sides.
The Leica binoculars have a feature that sets them apart in this area. They have two separate, independent center wheel adjustments for left and right diopters. Once you individually set the diopter correction for each eye - you "snap" the adjustment wheels together by pushing the top wheel down allowing you to focus both sides simultaneously to focus the binoculars.
Another thing you can look for is how the binocular creates an eyecup. Is the eyecup simply a rubber piece that can be folded over, or is it done as a built-in, retractable eyecup that can be set at an optimum distance for the user by screwing or pulling the built-in cup up or down.
A final feature that may make a difference to some users is the coatings on the eyepiece and objective lenses. Expensive binoculars will have "nano coatings" that give both abrasion resistance and water shedding ability so that droplets aren't formed on the lenses' surface and viewing remains relatively clear in fog, mist, and rain conditions.
Unfortunately, if you're buying binoculars over the Internet, you don't have the ability to handle the binoculars and make your own evaluation of the optics and mechanical build.
Last edited:
Vern Humphrey
Member
Two simple things you can do when evaluating binoculars. First, go outside and see how far away you can read the license plates of parked cars. You'll be surprised to find high magnification doesn't help much in this test.
Next, when you find binoculars that allow you to see the numbers clearly at a distance, repeat the experiment at dusk and see which binoculars crap out first.
Next, when you find binoculars that allow you to see the numbers clearly at a distance, repeat the experiment at dusk and see which binoculars crap out first.
I'm not sure what moderators and everyone else think, but IMO this post in itself is bona fide sticky material. A wonderful breakdown of major factors affecting the choice of binoculars, rifle scopes or any other optics for that matter.
Fantastic. Thanks, buckhorn_cortez.
.455_Hunter
Member
Steiner 8x30 man here. I have a daily pair for recreation/hunting/home use and a back-up pair for my GHB.
A larger exit pupil can mean more light passed into the eyes, but unless you're a youngster, your eyes may not dilate much larger than 5mm. An eye that dilates to just 5mm can only take in a 5mm beam of light whether the binocular's exit pupil is 5.25mm or 7mm. The very large exit pupils of "night binoculars" often go to waste on older eyes.
Last edited:
Pete D.
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light
This^^^^^^. Very true.
Image stabilization.....does not have to cost thousands of dollars. I have two IS binos...Fujinon 14X40s....meant for marine use, they will stabilize an image even from a small boat. Yes, they were not cheap but not in the arena with Swaros, etc. (they were just over a grand).
The set that gets much more use are the Canon 10X30IS that I referred to earlier...marvelous instrument at under $500.
This^^^^^^. Very true.
Image stabilization.....does not have to cost thousands of dollars. I have two IS binos...Fujinon 14X40s....meant for marine use, they will stabilize an image even from a small boat. Yes, they were not cheap but not in the arena with Swaros, etc. (they were just over a grand).
The set that gets much more use are the Canon 10X30IS that I referred to earlier...marvelous instrument at under $500.
buckhorn_cortez
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That's very true, but every reader of this forum doesn't have "older eyes" and may want to understand why a 7x50 looks brighter than an 8x42.
I'm 67 years old - my eyes fall into the "older eyes" category. I have a 7x50 and 8x42 binoculars. For me, the 8x42 provide all the performance I need and appear just as bright as the 7x50's in twilight use.
But, part of that may be that the 8x42 binoculars are Leica Ultravid with nearly 100% light transmission and extremely high contrast - all points you can pickup by very carefully reading what I've written and doing your own evaluation by simply using the information given.
What I'm trying to do, is give people the information to independently evaluate binoculars.
What we generally get in these type of discussions is, what I call, the "best chocolate cake" response.
Everybody has an idea in mind of the best chocolate cake they've ever had. I've had, what I consider to be, some really bad chocolate cake heartily recommended to me by people assuring me - "It's the best chocolate cake you'll ever eat."
It's the same with guns, optics, etc. People recommend their choices and want you to agree because it worked for them - it will work for you. They generally give no other reasons for the choice, just "This is what I have - you should like it too."
After all - why would they make a bad choice? Why would your choice be any better than theirs - and why would you not want to own what they own?
I prefer to make up my own mind, and I think most other people do to. What is not given in the chocolate cake response is the rationale used to make the choice. Given the reasons behind the choice, most people can decide whether they agree with the reasons or not.
People choosing an optic may not have enough information to do that with any kind of assurance they know what and how to make the evaluation.
I'm only attempting to give them a tiny bit of background material that will allow them to independently make up their own mind when purchasing binoculars - rather than simply trying to sift through all of the model recommendations with given with absolutely no relevant information or qualifiers as to why the choice was made.
Hopefully, there is enough information in my previous post that people who are not thoroughly familiar with optics will feel they have a basis for independently making a choice and not just taking a recommendation for the best chocolate cake...
People are far more likely to argue over 'value for money' than perceived quality. I doubt anyone here would use the top models from Leica, Zeiss, Swarovski etc., and decide that they're not that good. There are some absolutes in life. They might have the opinion that the cost isn't worth the incremental increase in performance though, which is a different discussion entirely. There are numerous sites with "how to choose a pair of binoculars" guides so the information is there for those that bother to look.
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