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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Big fan of Porro prism . (1 Viewer)

The Habicht's have a lot of deal breakers ,as far as, being a usable birding binocular. The biggest ones for me are the tight focus and the awful veiling glare.

Talking about '"the Habicht" is more than slightly misleading here.

There are three different models, and while they share a common history, they're somewhat different optically. Take veiling glare, for instance: The 8x30 is pretty bad (although not that much worse than the SV8x32 so many people apparently like here), the 10x40 is good, and the 7x42 with its small field of view is very good indeed. Clearly better than the great majority of roofs I know.

Hermann
 
Talking about '"the Habicht" is more than slightly misleading here.

There are three different models, and while they share a common history, they're somewhat different optically. Take veiling glare, for instance: The 8x30 is pretty bad (although not that much worse than the SV8x32 so many people apparently like here), the 10x40 is good, and the 7x42 with its small field of view is very good indeed. Clearly better than the great majority of roofs I know.

Hermann
Sorry, but I found the Habicht 8x30W much worse than the Swarovski 8x32 SV , as far as, veiling glare in my actual use. No comparison. The 8x32 SV is much better that the Habicht 8x30 W. The Habicht 7x42 is tunnel vision! I returned that model immediately.
 
Well guys, we all know there’s a never-ending parade of different individuals praising and condemning the very same binocular. The sad fact is that the usual hand held evaluations at normal magnification occur in an ever shifting borderland where binoculars with unknown aberration levels and possible sample defects meet testing methods that are inherently compromised, uncontrolled and unrepeatable. Is there any wonder that the basic optical characteristics of the instrument are so difficult to establish that way?

I’ll happily admit that I’ve deliberately searched for testing techniques that are controlled and repeatable, and will prevent my particular eyesight profile from unduly influencing the results. How can we hope to understand the complex interactions of individual brains and eyes with particular binoculars if we don’t first accurately establish the optical characteristics of the thing our eyes and brains are interacting with?

On the specific question of the usefulness of the USAF 1951 chart, I agree that it isn’t very good for visual resolution testing of binoculars at normal magnification. The lines are too short and the elements crammed too closely together for reliable readings when the apparent size of line pairs becomes very tiny. I think the NBS 1963 Resolution Chart would be better for that purpose. It has longer lines and wider separations between groups of line pairs. I’d like to have one, but I would want a vapor deposited glass slide like the USAF 1951 I use now and those are quite expensive.

Henry
 
Hello Henry, hope you had a nice vacation.

Have you used a NBS 1963A target? I find they have the advantage of longer lines but I find them very hard to use on boosted optics. The USAF 51 target is nested so as you zoom in the relative position stays the same, with the NBS target when you change groups you have to reposition the target, a real pain in the neck.

Like you said, the price is out of the question for the average bino tester. Using Edmund as a relative reference the following are for comparative purposes:

A group 1-18 mm/lp target (USAF group 4 element 2) is $200.
A group 1-180 mm/lp target (USAF group 7 element 4) is $275.
A group 1-512 lp/mm target (USAF group 9 element 1) is $750.
Note the above prices are for a single image.

A USAF from Edmund’s that goes to group 9 element 3 (645 lp/mm) is $625, single image.

For amateur use you can get a very decent target from China for $80-$100 that has both positive and negative vapor deposited images. I actually paid less recently for a couple of these.

http://www.ebay.com/itm/322346775033?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Or just search “resolution target”.

I have used the NBS 180 lp/mm target and do not get any noticeably different results in boosted images than I do with USAF, so unless you have a professional need for a specified target, I would not recommend the spending the difference but you may be able to find a NBS 163A from China or elsewhere for considerably less.
 
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Fight Friday!

Ladies and Gentlemen. Welcome to Fight Friday!

In the red,green and blue corner representing optics, real science and common sense is the tag team of Holger Merlitz and Henry Link. Holger is a professor of Theoretical Physics and Astro Physics, with a long record of reviewing Binoculars for over a decade. Henry is the one of the most respected optics experts in Birdforum, with many published reviews over a decade. He is also polite to a fault.

In the translucent and/or transparent corner representing the "common man" is RATHAUS! He is more than a match for the two nerds. He owns countless pairs of expensive binoculars and spends endless time watching the world pass by. The only data he provides in his well written comments is that his vision is 20/15. He was the first to observe the rare optical phenomenon of a strand of spider web through his Habicht porro. Scientists speculate that this could be the elusive proof of String theory. He is also from a place where the North star is not visible in the night sky and where the water in a drain spins counterclockwise.

Ok! Thats enough and let's start. Gentlemen, shake hands and let's have a clean fight.
 
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I'll just be a referee as I wouldn't know if it is a funnel-web spider or not.

There is the point, though, that the sensor for binoculars is the eye.

Testing binoculars without considering the sensor is of course essential, but eventually our eye/s have to come into play.

For each of us our eyes are different, and as one gets older vary a lot during the day and from day to day.

So there is a place for both sides.

I often test a binocular type and cannot believe it is the same as tested by birdwatchers here.
Sometimes I am totally at odds with other's conclusions.
This is because I come from a different start point. Astronomy, telescopes, lenses and eventually binoculars.
I am both an observer, and someone with a lifetime interest in optics.
 
Ladies and Gentlemen. Welcome to Fight Friday!

In the red,green and blue corner representing optics, real science and common sense is the tag team of Holger Berlitz and Henry Link. Holger is a professor of Theoretical Physics and Astro Physics, with a long record of reviewing Binoculars for over a decade. Henry is the one of the most respected optics experts in Birdforum, with many published reviews over a decade. He is also polite to a fault.

In the translucent and/or transparent corner representing the "common man" is RATHAUS! He is more than a match for the two nerds. He owns countless pairs of expensive binoculars and spends endless time watching the world pass by. The only data he provides in his well written comments is that his vision is 20/15. He was the first to observe the rare optical phenomenon of a strand of spider web through his Habicht porro. Scientists speculate that this could be the elusive proof of String theory. He is also from a place where the North star is not visible in the night sky and where the water in a drain spins counterclockwise.

Ok! Thats enough and let's start. Gentlemen, shake hands and let's have a clean fight.

Well, like I clearly stated, I do engage in "somewhat silly and specialised hobby viewing" :t:
 
Yes, this is entirely possible, and from my personal testing, most likely. The standard resolution test procedure is just one of countless possible tests....hence the amount of time I have spent devising other tests for the Habicht.

If Henry and others question the Habicht due to its results in a simple two dimensional black and white bubble jet printed resolution chart, then I must likewise question the performance of otherwise excellent alpha binoculars when they simply cannot resolve a single length of shaded translucent spider or worm thread, when the Habicht can. Can we devise a simple and repeatable version of this test in which others can likewise rank and file binocular performance?

Also, I must wonder if certain folk can be less compatible with a certain instrument. A highly complex interaction is taking place between human, binocular and target. If we want to become excessively analytical and reductionist, which is what happens sometimes with myself and others, then should we also be asking what biological profile the viewer has, including full eye function and all possible (and often unexpected) medications which can impact the viewing and brain/eye function (which can cycle in a 24hr basis)? I know about this first hand, from using myself as a guinea pig.

Perhaps we should also be asking if a two dimensional resolution chart is an appropriately challenging test? Is it just too overly simplistic compared to the inherent complexity of viewing in nature?

I still think Henry got a lemon ;)


Cheers,
Rathaus

Yes, indeed, it's a very complicated topic and subject to different evaluation methods. It's been known for many years that there is a major difference between line acuity and grating acuity as summarized by Hecht and Mintz (1939) in their seminal paper: "THE VISIBILITY OF SINGLE LINES AT VARIOUS ILLUMINATIONS AND THE RETINAL BASIS OF VISUAL RESOLUTION."

Note my deliberate reference to "acuity" as opposed to "resolution," which some purists insist (to put it mildly) belongs in the domain of pure optics, not visual perception. Be that as it may, as a psychologist I think it's most reasonable to evaluate visual instruments by how well they aid/hinder the various visual acuities.

Ed
 

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Yes, indeed, it's a very complicated topic and subject to different evaluation methods. It's been known for many years that there is a major difference between line acuity and grating acuity as summarized by Hecht and Mintz (1939) in their seminal paper: "THE VISIBILITY OF SINGLE LINES AT VARIOUS ILLUMINATIONS AND THE RETINAL BASIS OF VISUAL RESOLUTION."

Note my deliberate reference to "acuity" as opposed to "resolution," which some purists insist (to put it mildly) belongs in the domain of pure optics, not visual perception. Be that as it may, as a psychologist I think it's most reasonable to evaluate visual instruments by how well they aid/hinder the various visual acuities.

Ed

Hi Ed,

Just my 2 cents:

Different tests performed at different times with different subjects having different ranges of accommodation for different visual acuities under different conditions will produce different results. And, the armchair opticians aren't going to get around it. :cat:

Bill
 
Frankly, I don't care how good or not the Habicht's resolve. If they can't do it in sunny conditions they are worthless to me. Veiling glare is the Habicht deal breaker for me. Here is an interesting way to measure veiling glare.

"The image plane of an optical or imaging system normally receives not only the image forming radiation, but also stray light which can reduce image contrast. This unwanted radiation is referred to as veiling glare. The veiling glare of lens on its own can be considerably different from the veiling glare of a lens system and camera body combination. In the latter case, reflection of part of the image-forming radiation from the image sensor in combination with further reflections and scatter from the lens system and camera body contribute significantly to the veiling glare.

One method of measuring veiling glare is termed integral method. With the integral method, the target object is a small black area surrounded by an extended uniform source. The veiling glare index is specified as the ratio of the irradiance in the image of the black area to the irradiance in the image of the extended source. In general, the integral method is applicable to systems where the scene will normally be of roughly uniform radiance, for example a landscape imaged in overcast conditions or with the sun behind the camera or lens system."
 
Hi Ed,

Just my 2 cents:

Different tests performed at different times with different subjects having different ranges of accommodation for different visual acuities under different conditions will produce different results. And, the armchair opticians aren't going to get around it. :cat:

Bill

Well said!:t:

Bob
 
Hi Ed,

Just my 2 cents:

Different tests performed at different times with different subjects having different ranges of accommodation for different visual acuities under different conditions will produce different results. And, the armchair opticians aren't going to get around it. :cat:

Bill

Bill,

A properly executed resolution test perfectly gets round that problem by eliminating those variables, as I'm sure you know. ;)

David
 
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Have you used a NBS 1963A target? )

Hi Ron,

I experimented with comparing it to the USAF chart by making very large copies of both on photo paper, so that print quality would not be an issue, and then placed them next to each other at a long distance. Accurate sizing, wasn't required, just the same sizing for both. It was apparent just from backing up and using them as an eye test that it was a little easier to see the smallest resolvable line pairs on the NBS chart than the same size line pairs on the USAF chart.

Geez! Edmund's prices seem to be at least twice what they were when I bought my USAF slide ten years ago!

Henry
 
Bill,

A properly executed resolution test perfectly gets round that problem by eliminating those variables, as I'm sure you know. ;)

David

How does it get around the different subjects with different accommodation and different acuities? Or, for short, the human factor. Unless it eliminates them from the tests?

Bob
 
How does it get around the different subjects with different accommodation and different acuities? Or, for short, the human factor. Unless it eliminates them from the tests?

Bob

Sorry for my tardiness; I was at a Celtic Woman concert—good show!

While some of my respondents are undoubtedly smarter than me, on this particular issue I’m afraid I will have to leave my comment unaltered. I’m not as bullheaded as some think, but as long as there is a human element, I’ll be forced to let it stand.

Following is a snippet from one of my vignettes. Helpful? Certainly better than most speculation. Infallible? What month is it that pigs fly? :cat:

... A Test for Edge Resolution


Because edge sharpness is so important to some observers who speculate a great deal about exactly where an off-axis image starts getting soft, I hope to offer a quasi-scientific test to add a little data to the speculations.

I once believed the Nikon Prostar binocular provided a slightly crisper off-axis image than the Fujinon FMT-SX. I discussed this with a friend who wondered if I had a way to really know for certain; he, too, had an interest in the outcome. So I came up with the following test.

The Needed Particulars:

1. A rotary table graduated in degrees and fractions that’s either heavy enough to be stable lying on a flat surface or can be affixed to a rigid table top and precisely adjusted with a micrometer head or a smooth moving lead screw. I used a machinist’s 8-inch rotary table. It was heavy enough to be rigid just sitting on a table and had a micrometer adjustment.

2. A homemade “L” bracket or binocular tripod mount that uses a short ¼”-20 bolt to fasten to the binocular’s axle.

3. A round piece of metal turned to fit the hole in the middle of the rotary table and drilled to accommodate a short ¼”-20 bolt to fasten the “L” bracket or tripod mount to it. Other accommodations must be devised for tables not having a circular hole in the center.

4. A black and white resolution chart gauged at one line per millimeter placed on a well-lighted wall 30 feet from the rotary table. I used the black and white, 1951 US Air Force chart.

The procedure:

1. Note: Unless the binoculars to be compared—should a comparison be the goal—are of the same aperture and magnification the test will be invalid.

2. Secure the binocular on the “L” bracket or tripod mount to the center of the rotary table (or similar fixture).

3. Turn the dial of the rotary table to place the part of the resolution chart to be observed directly in the center of the field of the telescope you will be using for the test and set the angle to “zero.”

Note: To get the most from this test you should:

—Use the same telescope for all measurements.

—Use the same eye for all measurement.

—Always turn the micrometer or lead screw in such a way as to move the binocular in the same direction.

—Perform all the tests within a reasonably short time frame as fatigue, headaches, stimulants, or medications can affect visual acuity.

4. Start slowly turning the micrometer or lead screw to move the image of the resolution chart toward the edge of the field.

5. The instant the resolution chart turns to a solid gray box stop the test and note the results.

6. “Zero” the set-up and start the second iteration.

7. Perform the test 5 times in all being fastidious about stopping each iteration as soon as the resolution lines turn to a gray square.

8. Discard your lowest and highest readings and take the average of the 3 remaining iterations. This will give you a good idea about how far off-axis (or how close to the edge of the field) the binocular will resolve that particular resolution chart.

Although I was sure the Nikon provided a slightly crisper image, the test didn’t bear it out. Both binoculars resolved all the way to the edge of the field. Even when half the chart was out of the field for both, the remaining half continued to show individual resolution lines. A more aggressive and conclusive test might have been to move the resolution chart 10 feet farther away and perform the test again.
 
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Bob,

A properly executed resolution test does eliminate the human variables, quite unlike the procedure Bill describes which will be both acuity and accommodation limited. ;)

David
 
David, In your experience, what is the max. variation in center resolution, in arc seconds, within the same model of an "alpha" binocular (among different individual instruments of the model)? Within models of lesser optical quality? Thanks. Adhoc
 
Bob,

A properly executed resolution test does eliminate the human variables, quite unlike the procedure Bill describes which will be both acuity and accommodation limited. ;)

David

Hi David:

As this is a very important point for me (in that I will be sharing with others), I would like you to explain how this can be done. I don't see how the "human factor" can be removed except through totally relying on computers and digital imaging. I guess what I'm asking is: What do you consider "a properly executed resolution test"? In addition, how can this be of consequence since ultimately the binocular is going to be used by a REAL human with REAL eyes. I’m not trying to be difficult but this seems to be another treatise on “BB stacking.”
:cat:

Bill
 
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Hi David:

As this is a very important point for me (in that I will be sharing with others), I would like you to explain how this can be done. I don't see how the "human factor" can be removed except through totally relying on computers and digital imaging. I guess what I'm asking is: What do you consider "a properly executed resolution test"? In addition, how can this be of consequence since ultimately the binocular is going to be used by a REAL human with REAL eyes. I’m not trying to be difficult but this seems to be another treatise on “BB stacking.”
:cat:

Bill

Hi Bill, I thought I would take a whack at this while David gets his thoughts together since I used to do more of it in the past than anyone else on the forum.

The key to taking the eyes out of the equation is magnification. My visual acuity is pretty poor, about 90”, or about twice as bad as Kimmo and Henry. For instance if I expect a 7x bino to have about a 4” lp/mm I would need to use an auxiliary scope (booster) with at least 3.5x magnification to get to 24.5x total. This would allow, with my 90” acuity, to see about 3.7” of limiting resolution. I would choose a “booster” of higher magnification, ISO allows up to 45x, see attached excerpt from the ISO 14490-7 resolution specification.

Also note the picture of a test I did on a Zen Ray 7x36ED2 posted on the forum several years back. I think I reported at the time a resolution of 4”. Best I can remember now I was able to see group 7 element 1 very well but could not hardly see the vertical bars of element 2. I tried to take a picture of the result but have never been able to get a camera to focus well enough to get to the same point as I do with my eyes.

This is used to insure the bino meets the technical requirements and for comparing hardware to hardware. Optics metrics need to meet a certain level even if the average human may not be able to make full use of them. A bad resolution test usually indicates other aberrations in the system. The same reasoning for having standards for collimation, etc.

I think ISO 14133 sets out the limit of resolution. This protects consumers with no optics knowledge from buying a pair of Coke bottles joined together that would not make out a car at 50 meters. David (typo) has informed me there is a newer ISO standard out, but I do not have a copy of it.

An additional observation, with my acuity of about 90" a 10x bino would have to have a limiting resolution less than 9" to keep from limiting me. A person like Henry Link with an acuity of about 50" would need a limiting resolution of less than 5", very hard to do with objective in the 20-25 mm range.
 

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