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Optical Performance 8x56 FL vs 8.5x42 SV (1 Viewer)

BobP63

Active member
United States
I've been trying to find a direct comparison of optical performance between the Zeiss 8x56 FL and the Swarovision 8.5x42 and haven't had much luck. No surprise considering the physical size difference between these two binoculars makes it unlikely the same buyer or would consider them both a viable option.

If anyone can provide firsthand user impressions comparing the optical performance of the 8x56 FL to that of the Swarovision 8.5x42 it would be most appreciated. On the surface it would seem the Swarovision's physically smaller platform would present its designers with a significant technological uphill battle to overcome the advantage of more working space afforded to the designers 8x56 FL. Doesn't the old engine related adage "There's no replacement for displacement" apply to optics as well.

I've sampled the Swarovisions and find them truly impressive, I've not had such an opportunity to sample the 8x56 FL.
 
I haven't compared these two directly, but it's safe to say that the Zeiss has higher light transmission and more pincushion distortion while off-axis performance is certainly better and color bias is probably more neutral in the Swaro.

I can't say whether the Swaro matches the unusually clean and transparent appearing center field of the Zeiss in daylight, which is unmatched by any other binocular in my experience. The SV certainly looks fine in the center compared to its 42mm competition, but I wouldn't be surprised if, owing to lower axial aberrations, the Zeiss 8x56 center field image looks better in daylight, just as it does compared to the 8x42 FL. The next time I visit the local Swaro dealer I'll bring the 8x56 along.
 
Thanks Henry,
I'd be very interested in your impressions when comparing these two binoculars directly.

I'd also like to see the Docter 8x56 Nobilem thrown into the mix. Not as wide FOV, but almost no astigmatism, low distortion, pure "whites," and sharp nearly to the edge.

Here's the Polish group's review of the Docter:

http://www.allbinos.com/81-binoculars_review-Docter_Nobilem_8x56_B_GA.html

And here's their review of the Zeiss 8x56 FL:

http://www.allbinos.com/177-binoculars_review-Carl_Zeiss_Victory_8x56_T*_FL.html

Unfortunately, the 8x56 B/GA has been discontinued, according to the Polish reviewers.

From this reference under the photo of the Docter 8x58 roof and 8x56 Geovid:

http://www.allbinos.com/172-binoculars_review-Docter_8x58_B_CF.html

"When it comes to comparisons we can even go further than that. Next chart shows the Docter against a background of a very well-made Docter Nobilem 8x56 which has already been withdrawn from the production"

I wrote them today to make sure this wasn't a Googlefish mistranslation and also to ask if the Nobilem exhibits "rolling ball" since it has very low distortion.

Brock
 
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Thanks for the links, Brock.

It gives me an opportunity to complain once again about tests that rank binoculars with numbering systems. It's worth taking a close look at the methods and assumptions of these tests in the "How Do We Test Binoculars?" article. They resemble the efforts to quantify and rank dissimilar characteristics in the Cornell, Kikkert and other tests. I'm all for quantifying what can be measured, but assigning arbitrary numbers to subjective impressions, then adding up a grand total strikes me as useless.

It's easy to find many examples of assumptions and priorities in these numbers that would be irrelevant to a particular user. For instance, a downgrade for a narrow range of IPD adjustment means nothing if your IPD falls within the range available. Perhaps the most glaring example of an assumption is the notion that less "distortion" is better and therefore worthy of a higher number. Anyone who has followed Holger Merlitz work on this subject knows by now that low pincushion distortion causes the unpleasant panning effect of "rolling globe" in many people. Applying pincushion distortion is a design choice, not the failure to correct a distortion. The list could go on. The point is; don't take any of these numbering and ranking systems seriously.
 
Right on, Henry. I would even say further that the hellbentness of many reviewers to say which is better leads to specious findings of differences in areas where there is none.

The height of this nonsense is probably the comparison of telescope eyepieces. Rarely have I noticed any differences other than magnification and field of view, but a reviewer can take ANY two eyepieces made and pronounce one clearer, crisper and so on, than the other. Of course I'm supposed to think "His eyes must be a lot better than mine!". But I doubt it, since I do ok at seeing stuff.
Ron
 
Henry, I know the frustration that you are so diplomatically trying to express.

I will add to your comments that facts are measurements that can be made and duplicated by anyone using similar equipment and methods, therefore directly comparable.

If it cannot be measured and repeated, then it is opinion, and no amount of assigning a number to an opinion is going to make it fact.
 
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Thanks for the links, Brock.

It gives me an opportunity to complain once again about tests that rank binoculars with numbering systems. It's worth taking a close look at the methods and assumptions of these tests in the "How Do We Test Binoculars?" article. They resemble the efforts to quantify and rank dissimilar characteristics in the Cornell, Kikkert and other tests. I'm all for quantifying what can be measured, but assigning arbitrary numbers to subjective impressions, then adding up a grand total strikes me as useless.

It's easy to find many examples of assumptions and priorities in these numbers that would be irrelevant to a particular user. For instance, a downgrade for a narrow range of IPD adjustment means nothing if your IPD falls within the range available. Perhaps the most glaring example of an assumption is the notion that less "distortion" is better and therefore worthy of a higher number. Anyone who has followed Holger Merlitz work on this subject knows by now that low pincushion distortion causes the unpleasant panning effect of "rolling globe" in many people. Applying pincushion distortion is a design choice, not the failure to correct a distortion. The list could go on. The point is; don't take any of these numbering and ranking systems seriously.

Henry,

I agree about their number ranking system being arbitrary, particularly in the example you cited.

Ranking a bin higher that is used primarily for daytime activities because it has lower distortion even though pincushion creates a more natural view while panning the landscape (at least when used in moderation) is not only arbitrary but usually not desirable.

That's why I wrote them to ask about the "rolling ball" in the 8x56 Nobilem, which they ranked #1 overall. If it has a high degree of "rolling ball" like the Nikon HG and SV EL, it wouldn't be #1 on my list, and I wouldn't buy one.

Another case in point is the values given to edge performance. Take the example of the Swaro 10x40 Habicht:

"Blurring at the edge of the FOV

The blur occurs in the distance of 77% +\- 3% from the field of view centre.
5/10.0

Only a 5 out of 10 for edge sharpness out to 77 percent? That's pretty decent in my book, though what they don't include and what would make a difference for me is how slowly or steeply the sharpness falls off from that point to the edge.

I find bins with really blurry edges to be distracting, particularly while panning.

And I'm sure we could also make cases against other feature ratings.

But, I can understand the reviewers desire to create a number ranking system. Holger does this and so does Kimmo.

Holger has a disclaimer at the end of his reviews: The 'final score' is the sum of the individual scores and is intended to serve as an orientation only. Generally, it would be an over-simplification of the matter to just look which binocular has got the highest score, because it would obscure the individual features of the devices which differ quite a lot among each other.

I think the reason reviewers do rankings is because laypersons like myself lack the technical skills and, in some cases, also the samples to evaluate - the nearest alpha optics store to me is a 120-miles round trip.

So we depend on "expert reviewers" to guide us to which bin might be the best one(s) to buy.

In my case, I'm a bit better informed than perhaps some others, so when I see a bin whose distortion is rated 9 out of 10 because "the distance of the first curved line from the field centre compared to the field of vision radius is 79.5% +\- 4%," that raises a red flag, because those binoculars might have "rolling ball."

I also agree that IPD should not receive a number, but rather just be listed in the specs, and if a bin has a narrower range than most bins, mention that as a warning.

Having said that, I do appreciate having a site like allbinos where you can get some "hard data" for a number of features on a number of bins. I also like the way you can compare bins side by side:

http://www.allbinos.com/binoculars_compares.html

Here on BF, you have to search for that information in the archives and pull up separate pages to make your own comparisons, which is sometimes difficult to do if you don't know the correct search terms.

What I'd like to see on BF is something similar to what Edz has on Cloudy Nights - a separate section for technical reports.

However, this section would be fairly useless to the non-technically minded unless there was also a non-mathematical explanation of the terms and methods used in the reports to make them more understandable to a lay audience. Or perhaps a primer that one could read before reading the reports and use as a reference.

Brock
 
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Brock,

FWIW, I doubt that the Docter 8x56 Nobilem has much potential for "rolling ball" because the apparent field is so narrow. Even if pincushion is zero, angular magnification distortion doesn't start to kick in until about 40 degrees of apparent field. There's just not much room for it to develop.

I noted the curiously high light transmission plot of the Nobilem the first time I saw this review. It really should have very high transmission if the coatings are high quality. Provided the basic design is unchanged from the CZJ days it has a cemented Porro prism and probably uses a Kellner eyepiece and cemented objective, so maybe only 8 glass to air surfaces compared to 16 in the Zeiss FL. Even so it's hard to swallow a transmission curve that reaches 100%. If everything is done well a peak of around 97% would seem more believable.

The most interesting part of the FL review for me are the internal views. They show all four generations of Zeiss 8x56's starting with the FL at the top, then scrolling down, the Dialyt (very simple design like the Docter Nobilem), the DesignSelection and the first Victory.

Henry
 
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Henry, I know the frustration that you are so diplomatically trying to express.

I will add to your comments that facts are measurements that can be made and duplicated by anyone using similar equipment and methods, therefore directly comparable.

If it cannot be measured and repeated, then it is opinion, and no amount of assigning a number to an opinion is going to make it fact.

Surveyor.

Are you saying that optical performance is measureable? I totally agree, however and with all due respect too many contributors, is it not the case that like the reviews described previously, many of the "optical" and "what is best" discussions on bird forum are subjective, just like those reviews? The intentions in many cases are made for all the right reasons, however factually incorrect their opinions or finding's might be.

mak
 
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Hello Mak;

Yes, most are subjective opinions and I try to avoid unsubstantiated opinions, especially my own.

I was agreeing with Henry. Assigning a number and treating an opinion/preference as a measurement can have very misleading results.

For instance, I know I like a focuser with about 14 degrees/diopter speed, a torque of about 300 g/cm and a diameter that gives around 0.2 diopter per mm of rotation. I find binos like the Nikon LXL to be too fast and too smooth to suit me. I like to know when and how much I move the knob, the elephant snot on glass texture is not really to my liking. I really thought I would like it at first but it did not take me long to change my mind about that. The .75d standard deviation or 0.45d/mm is just to sloppy to suit me.

Now if someone like Brocknroller does a review, he likes very fast, smooth focusers and I did not know that, and he rated Brand X as a focuser = 8 and gave no other information, then compared it to a Minox model I have never used and rated that focuser as a 10, again with no other information and every other item receiving the same score I would be led to the conclusion the Minox was 20% better in Brock’s mind, and that may well be his feeling. For my uses a bino with a focuser of 4.5 degrees/diopter would not be tolerated, therefore the rating is totally misleading to me.

Someone recently made a post and said such-n-such 10x42 bino focused from 5 meters to infinity in 150 degrees of knob rotation. This is far better, I know that is about 7.5 deg./diopter and faster than I care for. I do not need to know anything further about the focus mechanism for that bino.

I would not buy a binocular from a subjective review (and everyone qualifies with try befor you buy), but if Henry or Kimmo or someone else did a review and measured the resolution, did a star test with no odd aberrations or did MTF and said optics were better than say 1 wave, told me the field curvature, pincushion, focuser details, eye relief details, etc. then I would know how it compared to my preferences and would order on that basis alone.
 
Dear Mr. Number Nazi,
It is good to point out that things that can be easily measured, should be. But, it seems to me that one could order a binocular on the basis of your criteria above, and the thing arrive and turn out to be uncoated, and give a dull, dim and lifeless view.

But what if Brock, that soft headed dreamer, said a binocular gave a view that was lifelike, contrasty, bright, and vivid, as if the binocular was transparent, and gave it 10+ on a scale in this area, where 10 was excellent? I pick him because he's not only unquantitative, he borders on antiquantitative. But he has lots of experience. We all talk enough to establish some baselines of agreement. The more I learn about eyes, the more it seems that normal eyes are amazingly similar, not different. Over and over, I find that even inexperienced observers remark of a great binocular almost always the same thing: "this one is so CLEAR." This is not a deeply esoteric quality that only enthusiasts can see, but it is one that remains unquantified.

It is unfortunate that we do not yet have a metric for this area of performance, because it is an essential view quality, perhaps the most important criterion. Oh, it hurts me, ouch! Certainly, transmission, and transmission vs color, is a good piece of it, and that can be measured, but it's not cheap nor easy. Veiling glare, as it affects large scale contrast, has not been quantified that I know of, and that may be another piece. Other optical pieces may contribute to the puzzle, I do not know.

But, given this sorry state of affairs, I feel bound to trying to understand reviewers, figure out where they're coming from, learn how much experience they have, and try to get something out of informed opinions on this most obvious and overwhelmingly important, in my opinion, optical issue. I'd rather have numbers too, but what can you do?
Getting Soft in Los Alamos
 
Dear Mister Optics Socialist;

I am glad that you are secure in your knowledge that mass opinion is infallible and therefore relieves you of any responsibility of your own statements.

But, concerning mass opinion, you may want to consider some of the following:

Nicolaus Copernicus and Galileo correctly realized that Earth moves around the Sun, not vice versa, and thus cannot be the center of the universe. Until very recently, Copernicus was not allowed to be buried in consecrated ground.

Flat Earth hypothesis. Although not a truly scientific theory, it was proved wrong by many scientific observations over a period of thousands of years, with evidence compiling and culminating in Apollo 11's images of a spherical Earth.

Phlogiston theory. Created to explain the processes of oxidation - corrosion and combustion - it was disproved by discovery of the fact that combustion is the reaction of fuel with oxygen and that corrosion is caused by oxidation of metals and the formation of compounds.
Geocentric theory of the solar system. Disproved by studies through astronomy, as well as the use of physics to predict occurrences that geocentrism could not. Whether Earth is really the centre of the universe remains to be seen, since we don't know exactly where the universe ends.

The classical elemental theory (that all substance is made of earth, air, fire and water). Disproved by the discovery of subatomic particles and the modern elements, as we know them today.

Aristotle's dynamic motion. It was an attempt at explaining momentum and why certain substances behave in certain ways; it was linked to the concept of the classical elements. Disproved by Galileo.

Ether as a carrier of light waves and radio waves. Disproved by study of the dual particle-wave nature of light, which means it does not in fact require a medium of any kind, and the simple complete lack of any evidence for such a substance.(Disproved by the Michelson-Morley experiment.)

Newton's corpuscular theory of light. While correct in many ways - it was the modern concept of the photon - it too was supplanted by the dual wave-particle theory of light that explains all aspects of it.

Newton's Laws of Motion (which were improved upon by Einstein - while not really proved wrong, the were shown to be not quite right either. For example in relativity or on the very small scale they don't hold).

While mass opinion is common and quiet powerful, opinions without fact or scientific basis can also be very dangerous. Consider the factions of politics and religion. Hunters and non-hunters. Football and soccer.

You can feel safe and secure in your knowledge that others agree with your opinions and you will be safe from discrimination, ridicule and persecution because your opinion of the best binocular is supported by everyone else’s opinion.
 
No problems Bob. I am just poking at RonH a little. He has expressed the view before that a consensus of opinion may be more relevant than facts. I assume that he is just poking fun at me too.
 
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Rons,

Alas, I think there's so much genuine tantrum throwing on the internet that good natured ribbing seems to require a winking smiley face.

I'm awarding this exchange the "Brocknroller Prize" for extraordinary achievement in going off topic. It only took a few paragraphs to move from binocular focusers to the entire intellectual history of the world.

Henry
 
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