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How do you do optical comparisons?

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John Barsness View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Barsness Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 16:14
Sgt. D,
 
One thing you are apparently not aware of (along with a number of other shooters) is that Schott is not a single glass factory. There are Schott factories all over the world, including in the U.S. and China. In fact, I have heard through my contacts in the optics business that glass from the Chinese factory is being favored by some companies because of the lack of environmental regulations over there. Cina can use some stuff in making glass that the European and even U.S. Schott factories can't--such as lead. Lead was a long-time standard component in high-density optical glass, but is outlawed in many places now. So even all Schott glass is not identical.
 
The coatings are indeed more important than the glass itself. Many factories do their own coatings, but as important as the coatings is the engineering behind them. One of the most persistent biases hunters have in optics is the notion that somehow there is magic in German "glass." Well, a lot of optical companies are buying glass and complete lenses from many places in the world, and in fact some of the so-called German glass in many optics is from elsewhere. What matters is the quality of the engineering, glass and construction.
 
All the optical companies are willing to bat around terms like Schott glass, proprietary multi-coating, etc. etc., which may or may not mean anything.
 
When I do my own testing of riflescope optics, I often ignore some of the things that advertising or even some hunters emphasize. For instance, in a big game scope I really don't give a darn whether the view is perfectly flat and sharp to the edges. This is because we don't aim with the edges of the field of view. We pretty much aim with the middle. (Binoculars are different.)
 
As mentioned above, I do some of the more informal type of testing that a lot of us do, by lining up a bunch of scopes and looking through them in different kinds of light. But when I get serious, I set up my own optical chart at a standard distance (in this case 25 yards) at sunset. This chart is a series of parallel black and white lines that descrease in size as they down the chart. It starts with a 1" black line, followed by a white line 2/3" as wide, then a black line half as wide as the first one, until at the bottom the last black line is 1/8" wide.
 
The sizes don't really matter as much as the principles. First, it ignores color rendition (which something else all together) but does test both brightness and resolution. The test is really simple. I aim at the chart and see how far down I can differerentiate black and white lines. Below a certain point everything appears gray--just as a series of black-and-white lines of the SAME size eventually appear gray at some distance from the eye. (Or a distant zebra appears gray, as those of you who've been to Africa have perhaps noticed.)
 
In making this test, I am careful to set all the scopes on the same magnification, s close as possible. I may fiddle with the magnification slightly, as the numbers on each scope do not always indicate exactly the same magnification. I also fiddle with the focus a little, because that also makes a difference.
 
Also, I only compares scopes of about the same size, and make sure I am testing them on a magnification that allows an exit pupil of at least 5mm and hopefully a little larger. For instance, last night I was comparing several scopes in the 3-10x range with 40mm objectives. I set them all on 6x, which meant the exit pupil was close to 7mm in diameter. That way I am testing the "brightness" of the glass, and not varying exit pupil sizes.
 
Also, I have all the scopes mounted on rifles, and the rifles on a steady rest, in a darkened room. You cannot really compare scopes unless they are very steady. I have heard of hunters looking through one scope on a rifle, then another scope they just held in their hand. This is NOT a valid comparison. Also, it is important for the room to be dark, so stray light does not interfere.
 
The end result of the test is pretty simple: I see how far down the chart I can differentiate black and white lines. This depends on the amount of light, obviously. Right at sunset all the lines are visible with any 3-10x scope set on 6x. Sometime during the next 45 minutes most scopers will arrange themselves into various classes. Sometimes the differences are so small that at full dark I still haven't picked them out, so then turn on a 100-watt bulb on the OUTSIDE of the building, so that it's light does not interfere with my vision either.
 
But even when I can see the same number of lines with two scopes, there are other visible differences. Usually the last line is a little sharper with some scopes than others.
 
I did this test last night with several scopes, but in particular wanted to test one that a number of people have been touting as incredibly sharp and bright during the last year or so. To put it bluntly, it failed to live up to the hype. All the other scopes allowed me to see an entire extra white line. The new wonder-scope wasn't even close, so now I am forced to wonder just what other people are seeing. Or what kind of tests they are making.
 
My own eyesight is apparently pretty good--for a guy who wears glasses. I don't have any  astigmatism, and so my eyes are easily corrected to 20/20 or so. I can still shoot very well with iron sights, even at 56, and can generally spot game as well as other experienced hunters.
 
One thing I have discovered is that a lot of what people think they see through a scope is mental, and often connected to price, or words like Schott. Which is why I set up my test the way I did, in order to eliminate those sorts of pyschological factors and see how different scopes compare.
 
I wrote a book about 10 years ago on optics that included the resuls of some scientific tests done in Germany of various scopes, as well as my own tests, which at the time weren't as scientific as they are now. Oddly enough, my own tests correlated pretty well with the German tests, which were made on very expensive equipment. They made some people mad, however, who expected their own scopes to test much higher. The tests in the book are way out of date, of course, since all optics have advanced considerably since then, one reason I didn't limit the book to those tests but also suggested ways people could do their own tests. Beyond the result of those German tests, however, the most interesting thing to me was the way some people reacted when reading them, because the tests did not always agree with their preconceived convictions about optics.
 
 
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Urimaginaryfrnd Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 16:23
I just look at the price tag -- that tells the rest of the story.  
 Bow
 
 
Actually I don't care if its the worlds best glass what I care about is does it come on target quickly and kill effectively, and its always nice to be able to dial in correction for distance. They havent made the perfect scope yet but Trijicon is getting close - once they figure out they need to put tactical knobs on a 2.5-10 and reduce it to 50mm with the 30 mm tube we will have reached the pinical of rifle optics.


Edited by Urimaginaryfrnd - February/22/2009 at 16:38

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shenko Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 17:11
The only way I've done actual A-B comparisons between scopes is by leaning some old garden tools against the back fence (everything is about the same color as a deer) and seeing how late I could still make out details.  Next time I do that, I'm going to include some colored objects.  Maybe red, blue, yellow, and green childrens' toys.  See if different colors show up better through different scopes.
Another thing I wonder about, is are identical scopes identical in performance.  I wonder if ten Bushnell 4200 2.5-10x40 (or whatever) scopes would perform indentically.
Mr. Barsness, I'm enjoying what you bring to these forums.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RifleDude Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 17:47
First, I only make "X is better than Y" declarations about scope models I own or have owned and have personally compared head to head.  Some scopes are immediately recognizable as being way better than others without having to do much, if any formal testing.  For example, comparing a $1800 Zeiss Victory series scope against the average scope retailing for $100 isn't going to yield any surprising results.

I frequently take my scoped rifles out to my hunting lease and set them up side by side on a bench or in one of my hunting blinds and compare in varying light conditions.  For resolution testing, I observe finely detailed objects with high contrast surfaces like tree bark, leaves, etc.  I view the scopes at varying angles toward direct sunlight at different times of the day to test for flare, image white-out, and ghost images.  I look for the presence of color fringing on objects against brightly lit backgrounds, such as tree limbs against a bright sky.  Simply shooting targets and seeing which scope gives me the sharpest view of bullet holes and target grid lines makes for a reasonably good comparison.  For scopes that initially appear to offer similar image quality, I also use the Air Force resolution target to see which scope can resolve the smallest set of black/white line pairs, much like the homemade chart Barsness describes.  Finally, I simply take 2 different scopes of the same configuration, set at the same power, and see which scope will still allow a shot at a predetermined object in the distance later into the evening as darkness approaches.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sgt. D Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 18:09
Quote   One thing you are apparently not aware of (along with a number of other shooters) is that Schott is not a single glass factory. There are Schott factories all over the world, including in the U.S. and China. In fact, I have heard through my contacts in the optics business that glass from the Chinese factory is being favored by some companies because of the lack of environmental regulations over there. Cina can use some stuff in making glass that the European and even U.S. Schott factories can't--such as lead.
.
 
 
That is the sort of thing I'm concerned about. You think you've found a nugget to help narrow the field or identify what makes great optics great. Then you find someone who knows better and your back to square one. Some have conceeded to "if it cost too much its a good one". Yes good components are expensive but paying one or two grand more for a S&B doesn't make it that much better than a Zeiss. And if a Kahles is as clear and tracks as good as a US Optics, why would I pay double for the USO? I really like the USO for alot of reasons, but if the coating on the schott glass is second to the same glass in the Zeiss it's not worth the same or more money as the Zeiss. But the manufactorers want us to be ignorant of these things so they can cut cost and keep us buying.
 
Yes it is best to take the scopes your interested in and compare in real world conditions, but up until recently that hasn't been an option. I guess that may put some pressure on folk that write reviews on such topics, cause its getting easier for the consumer to do it themselves.
 
From your statement above, I would want to find out what companies buy glass with lead in them so I can narrow the field to just those companies. Lead probably provides a better polish for a more clear glass and will bond better to coating.
Either way, can you define some of the different coatings? And which ones Zeiss and S&B use since they have been getting some of the better reviews? Or has someone else stepped up to the #1 spot?
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John Barsness View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Barsness Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 19:12
Unfortunately, no, the companies don't make their specific coatings public. In fact a lot of the inside information I've acquired has been in private conversations with people who'd had a few drinks. Some of it I can never reveal, at least until soemthing drastic changes That's the way life is. I have no idea about which companies buy glass from China, for instance, just that it is happening.
 
That is why I continually write about ways to test our own optics. Part of that is due to industrial secrecy, but most of it is due to the fact that that's the best way to do it. Our eyes vary, and products change from year to year. There is no way for anybody to write the "definitive" rating for various scopes, partly because they would have to test, say, 5 different scopes to find an average. Some are made on Monday morning, and next year the glass may come from somewhere else.
 
Sorry I can't be more firm about all of this, but that's the way things are.
 
All of this is also why I tend to distrust anybody who proclaims "X scopes are the very best in the world," or "Y's optics are twice as good as X's." Back when I started writing about optics in the 1980's things were much simpler, but around 1990 things started to change. Technology that used to be very proprietary started spreading world-wide. Parts started being made in various factories, sub-contracted to specs from an egineering firm on the other side of the world.
 
We like to think that optics are still made in one factory that does everything from making the glass to assembling the parts. It ain't that way anymore, and all of it changes so fast that nobody can keep up.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote opticsmike Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 19:45
It's been proven that the absolute best way to test scopes is to shoot some rounds out into the back woods at night with each scope, and when you hear a yelp you got a winner.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote huntingaddict Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 19:47
I'm positive you are correct about the lead thing is some glass.  I have known for a long time that US companies are not allowed to make the best chrome plated materials anymore.  All EPA regulations.  I'm sure the same could be true for glass. 

I do think that different vsion would have a drastic impact on what you would think of different optics.  I have some older friends that say that the really high end scopes with big tubes, etc. really help their older eyes.  Last time I was checked I had 20/10 in one eye and 20/13 in the other.  It may not quite be that now, but I have always been blessed with great uncorrected vision.  I'm not sure how that plays into my choices in scopes.

I'm going to have to get one of the resolution charts and probably an eye chart too and do some informal tests of my own that would be more scientific than the ones I have done in the past.

I am really surprised that there have not been more published tests of optics that really compare them scientifically for things like resolution and light transmission.  How about recoil testing them in an independent lab and run them till they break.  Then we'd know who really makes tough scopes and who sells pretty boxes.  They have no problem testing different rifles and proclaiming which are more accurate.  Why the lack of the same for optics.  It's really the same thing.  A Savage rifle that costs less shoots better than a lot of other rifles costing much much more.  I'm sure there are some real surprises out there in optics as well.  It's really the most frustrating product I have ever researched to try and buy.  Buying a $200 scope is not that much of a big deal to me.  I can compare them and be happy with my choice.  When you start talking 500-1000 scopes it gets a lot harder.  I don't want to buy a bunch of them and would like to be able to look at some real data to compare them.

I too really enjoy Mr. Barsness' information and perspective.  Everything he as says reminds me to look at what is most important in a hunting scope.  I'd like to setup one rifle as a tack driver for the range and the priorities can be different for that one, but not for my hunting scopes.  I get excited everytime I see a long post from him because odds are it's full of good information.  Thanks again.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Barsness Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 20:05

One thing I should have mentioned in the last post is that lead's main role in optical glass is the make it denser, so that it will "bend" light more. This is what lenses do, and the denser the glass the more light can be bent without losing other optical qualities.

The reason there aren't tests of scopes being "recoiled" into submission is that this breaks the scopes--unlike shooting rifles for accuracy. Not many companies are willing to submit scopes to be destroyed. In fact not many gun writers actually test scopes on rifles that really recoil. In my experience this requires at least a .300 magnum, and in the smaller .300's a rifle weighing 8 pounds or less with scope.
 
 
 
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 20:20
Anyone who wants their scope tested on a HARD KICKER, just send it to me.  I will be MORE THAN HAPPY to put it through its paces on my .458 Lott.   You supply the ammo, I'll supply the gun and shoulder to test it on.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Barsness Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 21:18
A .458 Lott will do the job. For some reason it is harder on scopes than some "bigger" cartridges.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cyborg Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 22:53
Shocked No...... I will not be sending ANY of my babies to you. You..... YOU  SCOPE SADIST!!!! Wink
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mike650 Quote  Post ReplyReply Direct Link To This Post Posted: February/22/2009 at 23:26
Originally posted by Kickboxer Kickboxer wrote:

Anyone who wants their scope tested on a HARD KICKER, just send it to me.  I will be MORE THAN HAPPY to put it through its paces on my .458 Lott.   You supply the ammo, I'll supply the gun and shoulder to test it on.  


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Post Options Post Options   Thanks (0) Thanks(0)   Quote opticsmike Quote  Post ReplyReply Direct Link To This Post Posted: February/23/2009 at 10:54
There are a few European articles that had documented endurance tests that were very extensive. The tests included extreme temperatures, solvents, and repeated excessive recoil. Zeiss came out on top in those tests, even faired better than S&B.

Edited by opticsmike - February/23/2009 at 10:55
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Post Options Post Options   Thanks (0) Thanks(0)   Quote hunter12345 Quote  Post ReplyReply Direct Link To This Post Posted: February/23/2009 at 11:21
My testing is just using them in real world hunting conditions.My favorite scope now is a Sightron S2 Big Sky 3-9x42.I used numerous scopes and yes at one time my favorite scope was a Redfield Ultimate Illuminator 3-9x56 and used that scope for over 10 years because it brought in the most light.That scope was replaced by a Nikon Monarch ,I have many rifles and scopes and the newer technology is a big improvement from the scopes of 20 years ago.I feel that Leupold is over priced and compares to the lower end Nikon Prostaff or Buckmaster.I like the Bushnell 4200 and Zeiss Conquest when they were selling for less than $350 which at that time was a god buy.For now you can find a good scope for less than $200.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Barsness Quote  Post ReplyReply Direct Link To This Post Posted: February/23/2009 at 12:49
opticsmike,
 
Zeiss has gotten quite serious about recoil resistance, especially since they introduced the Conquest.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: February/23/2009 at 18:14
OK, so just send me all your Zeiss products and I will give them a thorough test for you. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Horsemany Quote  Post ReplyReply Direct Link To This Post Posted: February/23/2009 at 18:23
It would be nice to hear what ILya has to add to the subject of scope testing.  I'm sure he's done as much of it as anyone. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JGRaider Quote  Post ReplyReply Direct Link To This Post Posted: February/24/2009 at 09:47

John, as usual I've thoroughly enjoyed this conversation.  Are you at liberty to tell us the results, name names, of your test.  I'm interested as to which "wonderscope" you were not impressed with.  Thanks.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Barsness Quote  Post ReplyReply Direct Link To This Post Posted: February/24/2009 at 13:12
I'll be making an extensive post next week on not just that scope but a couple of others that were recently tested. Names will be named.
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