How to choose between "cherry" and "lemon"? (1 Viewer)

Well, if i am to abide by the conventional wisdom that a porro prism Nikon SE 8x32 has the greatest optics on Earth, then i should see a difference when comparing them side by side with an inferior glass such as a roof prism Swarovski EL 8x32.
Well, i took both of them outside in the yard this morning, and performed my own hillbilly version of testing for two hours. After extensive resolution testing (looking at the neighbor's farm and at rose bushes in the distance while resting elbows on a cattle fence), the only difference that i can really see is that the EL has a field of view slightly wider, and that in the EL images seem slightly larger. I can't see that any of these glasses is brighter or that it has better resolution than the other, nor do i see any real difference in color perception. I tried hard to dismiss the EL by looking for color fringing, but i could not find any. Which means that either the SE is a lemon, or the EL is a cherry. My eyes are not perfect either,
Now, this brings me to my question:

Let's suppose that someone has decided what they want, and they go to a huge store such as BassPro or Cabelas or Eagle Optics, and says "I will buy one xyz but i would like to look through 3 samples, just to make sure that i get a good one." Now, we are talking $1600 optics here, in a store that may have optic charts on the wall, but in mostly fluorescent light, and taking 3 pairs of Zeiss outside for a test is not likely to happen. So how would you check to make sure that you are not dishing dough on a lemon? What should i look for in the 2 hours before they call security to take me to the nut-house, where i rightfuly belong as an opto-obsessed?

Luca said:

and taking 3 pairs of Zeiss outside for a test is not likely to happen.

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Are you sure? They probably aren't going to let you head off to a favorite birding spot, but I was allowed to step outside to test a Leica Ultravid 8x42 at Scope City in San Diego, and I was allowed all the time I wanted.

Curtis Croulet said:

Are you sure? They probably aren't going to let you head off to a favorite birding spot, but I was allowed to step outside to test a Leica Ultravid 8x42 at Scope City in San Diego, and I was allowed all the time I wanted.

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Ok, so i'll take the 3 pairs with me outside the BassPro shop in Columbia MO, where they have a duck pond. What should i look for to avoid a "lemon"? Just trust my gut and get the one that i like better, or try some sort of a test?

Luca said:

Well, if i am to abide by the conventional wisdom that a porro prism Nikon SE 8x32 has the greatest optics on Earth, then i should see a difference when comparing them side by side with an inferior glass such as a roof prism Swarovski EL 8x32.
Well, i took both of them outside in the yard this morning, and performed my own hillbilly version of testing for two hours. After extensive resolution testing (looking at the neighbor's farm and at rose bushes in the distance while resting elbows on a cattle fence), the only difference that i can really see is that the EL has a field of view slightly wider, and that in the EL images seem slightly larger. I can't see that any of these glasses is brighter or that it has better resolution than the other, nor do i see any real difference in color perception. I tried hard to dismiss the EL by looking for color fringing, but i could not find any. Which means that either the SE is a lemon, or the EL is a cherry. My eyes are not perfect either,
Now, this brings me to my question:

Let's suppose that someone has decided what they want, and they go to a huge store such as BassPro or Cabelas or Eagle Optics, and says "I will buy one xyz but i would like to look through 3 samples, just to make sure that i get a good one." Now, we are talking $1600 optics here, in a store that may have optic charts on the wall, but in mostly fluorescent light, and taking 3 pairs of Zeiss outside for a test is not likely to happen. So how would you check to make sure that you are not dishing dough on a lemon? What should i look for in the 2 hours before they call security to take me to the nut-house, where i rightfuly belong as an opto-obsessed?

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I don't think you are going to have many lemons when you are comparing that level of binoculars. They will all have strong and weak points but in the end it will be up to you to decide which pair you like the best. At that level they will all be excellent. It depends upon what characteristic you value the most in a binocular. On axis sharpness, depth of field, brightness, or maybe ergonomics. Which one do you get the least blackouts with? In the end decide which pair YOU like the best and it doesn't matter what somebody else likes. The Swarovski EL 8x32's are excellent binoculars , and so are the Nikon SE's. I know that everybody says the Nikon SE's are supposed to be better optically but I have compared them like you and I too could see little difference. I personally prefer the Swarovski's because I get too many blackouts with the Nikon SE's and I love the 3D like effect you get with the Swarovski's because of their great depth of field. I also love their ergonomics and feel in my hands.But that is personal preference.

Dennis

I guess another thing you should test is performance at low light levels (dawn or dusk) which may highlight more of a difference between the models you tested, but could be hard to arrange at your local store!

MSA said:

I guess another thing you should test is performance at low light levels (dawn or dusk) which may highlight more of a difference between the models you tested, but could be hard to arrange at your local store!

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I think this really hits the mark. In my experience differences between any decent binocular are harder to see in bright light. Even my low cost Nikon Sporters perform very well in the bright of day. It is in the dim light of dusk and dawn that I can really see differences in performance between binoculars. Those Sporters hold up very poorly under those conditions.

Greetings!

Luca said:

...and taking 3 pairs of Zeiss outside for a test is not likely to happen...

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Why not? Locally, you can carry up to 4 pair at a time out the front door at one shop, and up to 2 pairs at several other shops. All they require is that you leave your drivers license and/or wallet with them while you evaluate outdoors, and that you don't drop or otherwise damage the optics.

Best wishes,
Bawko

Luca,

If you are serious about separating the cherries from the lemons you will need to "star" test the binoculars. It's quick to do once you know how, but it requires a tripod and a "star" in the form of a tiny reflection of the sun. At stores I usually use reflections in the shiny parts of cars in the parking lot.

The biggest difficulty in star testing binoculars is that the magnification is too low unless you use a "booster" behind the eyepiece of the binocular being tested. THe easiest thing to use for store testing is a second small binocular (30mm or less) hand held behind the eyepiece of the tested binocular (which must be tripod mounted). The idea is to use the diffraction pattern of the "star", both in and out of focus, to analyse the aberrations and defects in the optics. Because of the fast optics all binoculars have pretty large amounts of chromatic and spherical aberrations. Some are worse than others, but don't expect to see anything close to a perfect diffraction pattern. What you hope to see is a circular bull's eye of strong rings on one side of focus and very weak or no rings on the other side. Many binoculars have so much spherical aberration that there are no rings on either side of focus. The main sample defects you encounter in binoculars are astigmatism, coma from miscollimated optics in a single barrel and pinched optics from too much mechanical pressure somewhere. Astigmatism causes the bull's eye of diffraction rings to be elliptical rather than circular, miscollimation will cause the bright central spot of the bull's eye to be off-center and pinching will distort the shape of the bull's eye. The key is to learn to interpret what you see. Sometimes several defects will be present together.

I've posted on this subject a few times, so I know most people don't want to do this and learning how isn't so easy. The description above is just a quick introduction. If you google "telescope star test" you will find much more. If you can get the hang of it you can very quickly identify the lemons. And believe me they are there even among the expensive binoculars.

Henry

P.S. Even tripod mounted and using a resolution chart you're not likely to see any difference in center of the field "resolution" between any two decent quality 8x binoculars. They all have much higher resolution than the eye can see.

Luca: There are many issues, including distortion, field of view, colour casts, edge softness, and flare. In one binocular I tried flare was apparent in twilight conditions, making it difficult to use. Some people dislike the soft edges of the Zeiss FL range, but I have no problem with it. I dislike the CA of the Leica and others, whilst many are not troubled by it. CA tends to be most visible on a bright day. Some bins have noticeable distortion, which causes a weird effect when panning. Various people comment knowledgeably about colour casts, but I'm damned if I can see them! (Due to my ignorance no doubt.) Contrast and transmission differences will show up in low light.

As an aside, the main determinant of how much detail you can see through a bin is the magnification. However, you can use a suitable target such as a dollar bill test to see how far away you can get from a target and still read the text. (I know Henry will disagree with me here.) I believe that any differences you see are due to differences in contrast. IMO for high quality binoculars the differences are not significant.

To be honest, after lots of threads on BF, I'm coming to the conclusion that despite all the arguing here on BF, you are best to just try bins during a field day, or in the back yard of a shop, and buy the ones you like. Handling and feel are as important as the optics, and all bins are a compromise.

Incidentally I would be one of the first to extol the virtues of the Nikon 8x32 SE, but it is clear from BF threads that many people have serious problems with blackouts. However, last Saturday at Sharpenhoe Clappers, I met someone using a new Nikon 8x32 SE. My first tick!

Leif

Luca said:

Well, if i am to abide by the conventional wisdom that a porro prism Nikon SE 8x32 has the greatest optics on Earth, then i should see a difference when comparing them side by side with an inferior glass such as a roof prism Swarovski EL 8x32.

Click to expand...

Conventional wisdom is an oxymoron.

Well, i took both of them outside in the yard this morning, and performed my own hillbilly version of testing for two hours. After extensive resolution testing (looking at the neighbor's farm and at rose bushes in the distance while resting elbows on a cattle fence), the only difference that i can really see is that the EL has a field of view slightly wider, and that in the EL images seem slightly larger. I can't see that any of these glasses is brighter or that it has better resolution than the other, nor do i see any real difference in color perception. I tried hard to dismiss the EL by looking for color fringing, but i could not find any. Which means that either the SE is a lemon, or the EL is a cherry.

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Or, the EL meets your personal performance criteria better than the SE.

My eyes are not perfect either,
Now, this brings me to my question: Let's suppose that someone has decided what they want, and they go to a huge store such as BassPro or Cabelas or Eagle Optics, and says "I will buy one xyz but i would like to look through 3 samples, just to make sure that i get a good one." Now, we are talking $1600 optics here, in a store that may have optic charts on the wall, but in mostly fluorescent light, and taking 3 pairs of Zeiss outside for a test is not likely to happen. So how would you check to make sure that you are not dishing dough on a lemon? What should i look for in the 2 hours before they call security to take me to the nut-house, where i rightfuly belong as an opto-obsessed?

Click to expand...

One distinction is that not buying a lemon, which most of us would like to avoid, is not quite the same as finding a cherry, which is closer to what Henry is doing. The difference is that he has defined optical performance criteria, and a methodology, and we have not. Leif, on the other hand, suggests that the cherry is the binocular one really likes best. Different criteria but just as valid, since Henry's perfectly formed star, could still be seen in Leif's sour cherry —*the best of a bad thing doesn't make it any better, so to speak.

As to whether star testing for cherries is worthwhile, it would be helpful if there were empirical evidence that experienced birders can appreciate the differences in the field. Such experiments could be done in several ways fairly economically, but double-blind procedures would be essential, and the results would also require basic statistical analysis. Until then, what I can't see ain't there. Well, I guess it might be there, but my mind is not. You know what I mean.

Ed :smoke:

elkcub said:

One distinction is that not buying a lemon, which most of us would like to avoid, is not quite the same as finding a cherry, which is closer to what Henry is doing.

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Ed,

I think star testing works about equally well for avoiding lemons or picking cherries. I seldom star test a binocular that looks perfectly assemblied, and it's true that even a binocular with a pretty poor looking star test can often be tolerated because of the low magnification. Unfortunately I think it requires some experience to know when a defect in a star test is severe enough so that it can't get by and will eventually cause dissatification, though maybe not right away. For myself I prefer to buy binoculars with no more than slight defects which I'm certain will be invisible. Star testing makes that easy for me, but mostly I've given up recommending binocular star testing to others because I know it's not that easy to do at first. I only mentioned it here because Luca was specifically asking for such a test.

Henry

Unfortunately I think it requires some experience to know when a defect in a star test is severe enough so that it can't get by and will eventually cause dissatification

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Henry,

Too bad we don't have your experience to distinguish slight defects. :h?:

Listen, I've been meaning to mention that you get Elkub's highest praise as a trained observer. Your comments about astigmatism and field curvature on the flat field thread were truly stunning, — and conform exactly with the textbook characerization of field flatteners.

Ed

Ed,

Thanks, it's an honor to have Elkcub's highest praise bestowed on my humble efforts. ;-).

Could be I overstated my ability to distinguish slight defects. The beauty part about star testing is that it takes a lot of the guess work out of detecting defects and figuring out what's causing them. After about one minute of star testing you'll know quite a bit about whether there is a defect, what it is and how bad it is, without even having looked through the binocular in the normal way.

Henry

Whether or not astigmatism etc are visible through a low power binocular is not something I know about, and I will leave that issue to Henry and others. But from my own limited experience, one common aberration to look out for is mis-collimation.

I once had a miscollimated binocular which gave me eye strain after prolonged use. It also had very shallow DOF in the mis-collimated optical assembly. I was told by a well known optics seller in the UK (who spotted the problem for me) that miscollimation is not uncommon among brand new binoculars from at least one big name. I will not name them as I have no proof of his claim, and I would not want to single out one brand. IMO anyone buying a binocular should at least examine the pair they might buy to check for collimation. How one does this is not clear, except that if they are okay for prolonged use, then they are probably collimated properly.

Leif

Thank you all. That really was helpful. I have a doubler, and i can do a star test in the store and outside. I am not sure either that "the perfect one" will make a difference in the field, but it sure will in my mind.
I am slowly reducing the collection, i will keep 3 binoculars (Leica Ultravid 10x42, Swarovski EL 8x32, and a third yet to be decided), and my wife and my daughter will have their own. As my daughter said that she prefers using my EL 8x32 after i ruined her Pentax, i was thinking of finding another one for myself and picking a cherry.

Henry –

Thank you for the help in distinguishing between binoculars that are lemons and those that are cherries. I have two questions.

1. Does your advice – that "what you hope to see" when star-testing binoculars "is a circular bull's eye of strong rings on one side of focus and very weak or no rings on the other side" – also apply to the star-testing of scopes (say, the 60-65 and 80-85 mm. offerings from Nikon, Leica, Swarovski, and Zeiss)? Or should a good birding scope provide a more even star test on both sides of focus than a good pair of binoculars?

2. Does it matter on which side of focus the strong rings and bull's eye appear?

Avron

Frankly, I don't know how this would work for high end binoculars, but years ago, I used to work in a store that sold riflescopes. Outside the store was a large street with varying levels of traffic. Around dusk I used to try various scopes to see if I could see something accross the street (about 75 to 100 yards away) from inside the lighted store.

The differences in various scopes was simply astounding. With some I couldn't see anything whether there were cars going by with their lights on or not. Some, I could see someone walking on the other side of the street and some I could see everything in detail including writing on signs, buildings, etc. with and without intervening glare from cars. I could even see drivers in cars through all that glare, some just like I was standing next to them in daylight.

After complete darkness the same scopes stood out. With no traffic, some scopes could easily discern writing in dark areas- others I couldn't even see the building.

Its not a very easily measured test, but the differences were so obvious I didn't need to measure. Mostly this is a test of light gathering and seeing through glare. Tells you nothing about how true the colors are, ultimate resolution, color fringing or collimation, but I would be extremely upset if I paid top dollar for a set of binoculars and found that they didn't do well in this type of test. Outdoors, the sun and water provide plenty of glare and many birds are most active at dawn and dusk. If you can't see it, what difference does it make if the colors are true?

Maybe all good binoculars these days would pass such a test, but I sure would like to know if they do before even thinking about more esoteric qualities.

Don

Avron said:

Henry –

Thank you for the help in distinguishing between binoculars that are lemons and those that are cherries. I have two questions.

1. Does your advice – that "what you hope to see" when star-testing binoculars "is a circular bull's eye of strong rings on one side of focus and very weak or no rings on the other side" – also apply to the star-testing of scopes (say, the 60-65 and 80-85 mm. offerings from Nikon, Leica, Swarovski, and Zeiss)? Or should a good birding scope provide a more even star test on both sides of focus than a good pair of binoculars?

2. Does it matter on which side of focus the strong rings and bull's eye appear?

Avron

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Spotting scopes are subject to exactly the same optical defects as binoculars and for the same reasons, but the effect on the image quality of scopes can be worse because of the higher magnificaton. However, a good specimen of a birding scope should have lower aberrations than a good binocular because the focal ratio is higher. Most binoculars are around f/4. Most birding scopes fall between f/5,5 and f/7, so I would hope to see a considerably better star test from a scope than a binocular.

Which side of focus has strong rings is determined by whether there is under or over correction for spherical aberration. I'm pretty sure the effect on image quality is the same. A scope with perfect correction will show an identical pattern on both sides of focus, something you are not likely to see in a birding scope.

Henry

Ripantuck said:

The differences in various scopes was simply astounding. With some I couldn't see anything whether there were cars going by with their lights on or not. Some, I could see someone walking on the other side of the street and some I could see everything in detail including writing on signs, buildings, etc. with and without intervening glare from cars. I could even see drivers in cars through all that glare, some just like I was standing next to them in daylight.

After complete darkness the same scopes stood out. With no traffic, some scopes could easily discern writing in dark areas- others I couldn't even see the building.

Don

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I've seen exactly the same thing with binoculars. Comparing a Zeiss 8x30 Classic, a Nikon 8x40 Earth And Sky and a Viking 8x40 at dusk, and viewing house roofs, I could see nothing with the Viking, quite a bit with the Nikon, and a lot with the Zeiss despite the smaller objectives. The difference was due to the better transmission and contrast of the Zeiss. Quality is as important as aperture when light is low.

Leif