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Lotutec irritation?

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Old Sunday 23rd June 2019, 12:17   #1
Swissboy
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Lotutec irritation?

I have recently bought a new 8x32 FL. And unlike my older 8x42 FL or the 8x32 FL demo model I had while waiting for the new binoculars, this new one tends to irritate me every once in a while with a very intense orange-reddish shine before the binoculars are on my eyes. The only explanation for this, I think, is a too strong coating on the oculars' outermost lenses. I guess it must come from the Lotutec coating? At least, the older versions I mentioned above neither show the red coating nor the irritation described here.

The effect varies and it is most pronounced under bright overcast skies. Also, I think it affects me particularly as I need to keep my regular eye-glasses on while using optics like scopes or binoculars. Thus, there is a gap between the oculars and my eyes that can't be fully closed. So even while using the binoculars, there is at times an orange-red spot at the edge of my vision.

It is rather difficult to get a decent photo of the problem. So, the pictures attached here only partially show the reflection. The bright ring on the rim can go all around on both oculars when conditions are "right".
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Last edited by Swissboy : Sunday 23rd June 2019 at 12:27.
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Old Sunday 23rd June 2019, 21:06   #2
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The Lotutec coating on my Lotutec 8x32 FL is as red as you mention. The non Lotutec coating on our 10x32 FL is almost colorless in comparision.

I'm always wearing glasses, but I never had such problems with my 8x32 FL.
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Old Monday 24th June 2019, 01:32   #3
NDhunter
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Zeiss Lotutec lens coatings are simply a hydrophobic coating to help water droplets shed for viewing
under wet and rainy conditions. This coating does not offer any anti-relective or other properties.
There are many layers of coatings on lenses, this is just one of them.

What you are seeing has nothing to do with Lotutec. Many companies offer coatings like this, they have nothing to
do with optical properties and their design.

Jerry
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Old Monday 24th June 2019, 06:55   #4
Troubador
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Robert
When you say the red colour irritates you, do you mean that as you bring the FLs closer to your eyeglasses, there is sometimes a flash of red colour that distracts you or that you find annoying?

And you mention and orange 'spot' (which means orange in one place) but also a bright rim that can sometimes go all the way around (which means orange everywhere around the edge). So, is it a spot or is it a ring? Or can it be both at different times?

I apologise if this seems like an interrogation but I never saw anything like this in my years of using FL32 (and 42) or indeed two SFs that also use Lotutec.

Lee
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Old Monday 24th June 2019, 09:19   #5
Swissboy
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Quote:
Originally Posted by Troubador View Post
Robert
When you say the red colour irritates you, do you mean that as you bring the FLs closer to your eyeglasses, there is sometimes a flash of red colour that distracts you or that you find annoying?

And you mention and orange 'spot' (which means orange in one place) but also a bright rim that can sometimes go all the way around (which means orange everywhere around the edge). So, is it a spot or is it a ring? Or can it be both at different times?

I apologise if this seems like an interrogation but I never saw anything like this in my years of using FL32 (and 42) or indeed two SFs that also use Lotutec.

Lee
Lee, I think you are getting it correctly. The situation differs, and usually there is no irritation at all when I look through the binoculars. But there are two situations where the irritation is pronounced. For one, when there is a bright overcast sky, then the bright ring shown in the photos goes all around when I look down at the eyepieces. And when I quickly move the binoculars to my eyes to focus on an object, I tend to get distracted for a moment. The orange spot, is what can at times be visible even when the binoculars are in viewing position. This spot is a result of the fact that my eyeglasses tend to leave a gap for light to enter from the side. There can be a similar irritation without the orange color resulting from backlighting, and that type of irritation also happens with my older non Lotutec (or should I say non red-coated) 8x42 FL. It's the familiar situation that can be avoided by shielding the gap with a hand. Comparatively, the additional irritation from the red spot is minor, yet nevertheless a fact.
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Last edited by Swissboy : Monday 24th June 2019 at 09:21.
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Old Monday 24th June 2019, 16:07   #6
Binastro
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This is a real problem if it spoils the view.
The rear surfaces of the binocular eyepieces appears to be flat like a mirror, although I am not sure, as some eyepiece rear elements are concave and even convex.

The best solution would be to have a binocular without the red coating, but this may be an expensive change.

Otherwise one just puts up with it or uses special eyecups or shields.

I have noticed similar effects with some binoculars although I don't wear glasses.
If annoying, I just use another binocular.

B.
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Old Monday 24th June 2019, 16:37   #7
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Thanks Robert and sorry to hear about this distraction. Hope it doesn't spoil your enjoyment too much.

Lee
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Old Monday 24th June 2019, 16:41   #8
Swissboy
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Quote:
Originally Posted by Troubador View Post
Thanks Robert and sorry to hear about this distraction. Hope it doesn't spoil your enjoyment too much.

Lee
Wish I could trade my new model for the demo model I had while my FL 8x42 was at Zeiss for repairs. That was the perfect 8x32 for me. But, apparently, Zeiss does not sell those demo models. Should I claim they want to keep the best for themselves?
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Last edited by Swissboy : Monday 24th June 2019 at 16:45.
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Old Monday 24th June 2019, 16:53   #9
Troubador
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Quote:
Originally Posted by Swissboy View Post
Wish I could trade my new model for the demo model I had while my FL 8x42 was at Zeiss for repairs. That was the perfect 8x32 for me. But, apparently, Zeiss does not sell those demo models. Should I claim they want to keep the best for themselves?
Was that bino loaned to you by Zeiss while your 42 was being repaired?

Perhaps you just didn't encounter the light conditions that cause this irritation when you had the loan bino.

Lee
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Old Monday 24th June 2019, 17:51   #10
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Quote:
Originally Posted by Swissboy View Post
Lee, I think you are getting it correctly. The situation differs, and usually there is no irritation at all when I look through the binoculars. But there are two situations where the irritation is pronounced. For one, when there is a bright overcast sky, then the bright ring shown in the photos goes all around when I look down at the eyepieces. And when I quickly move the binoculars to my eyes to focus on an object, I tend to get distracted for a moment. The orange spot, is what can at times be visible even when the binoculars are in viewing position. This spot is a result of the fact that my eyeglasses tend to leave a gap for light to enter from the side. There can be a similar irritation without the orange color resulting from backlighting, and that type of irritation also happens with my older non Lotutec (or should I say non red-coated) 8x42 FL. It's the familiar situation that can be avoided by shielding the gap with a hand. Comparatively, the additional irritation from the red spot is minor, yet nevertheless a fact.
The "orange spot" issue is caused by reflections of side light by the ocular lenses and a simple fix is using your hand to shield the eyepieces, as you said yourself. I have four Victory FL binos (including both 32mm models) and all have this "issue", but I doubt there exist any binos that do not, to a greater or lesser extent! (I am sure that the demo FL had this issue too, but likely you did not test it in the light conditions that cause it).

The other issue you described is more serious: it is caused by internal reflections, typically from edges of the prisms. You can use your hand as an umbrella above the objective lenses to reduce this effect. But, according to my experience:
-the FL 56mm models do not suffer at all from this problem
-the FL 42 mm models are affected by it to a larger extent
-the FL 32mm models have quite a good control of internal reflections, better than the 42mm FLs.
In sum I think there is something wrong with your 8x32 FL and you should return it to the dealer and ask for a replacement.

Last edited by PeterPS : Monday 24th June 2019 at 17:54.
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Old Monday 24th June 2019, 20:16   #11
Swissboy
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Quote:
Originally Posted by Troubador View Post
Was that bino loaned to you by Zeiss while your 42 was being repaired?

Perhaps you just didn't encounter the light conditions that cause this irritation when you had the loan bino.

Lee
I had it for several weeks, so it is hardly possible that the condition would not have occurred at times.
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Old Monday 24th June 2019, 20:20   #12
Swissboy
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..I am sure that the demo FL had this issue too, but likely you did not test it in the light conditions that cause it...…….

…………………...
It did not have the red coating just like my own 8x42 FL does not. Thus, the specific irritation is simply not there.
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Old Tuesday 25th June 2019, 12:45   #13
PeterPS
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Quote:
Originally Posted by Swissboy View Post
It did not have the red coating just like my own 8x42 FL does not. Thus, the specific irritation is simply not there.
If you really think that the Lotutec coating is the problem why don't you buy an FL 8x32 without Lotutec. They show up quite often on the second hand market and, of course, they are less expensive than a new FL 8x32. They can be easily identified by the fact that the rims of the eyecups are not rounded and there is no umbrella symbol over 8x32.
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Old Wednesday 26th June 2019, 06:06   #14
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Generally, when I'm outdoors I wear a broad-brimmed hat - I'm bald and I need to protect the top of my scalp. The brim of my hat also serves to shield the oculars of my binoculars from a lot of stray light - and helps keep rain off the lenses of my spectacles too. Such a solution might help you, perhaps?
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Old Sunday 7th July 2019, 11:43   #15
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Dear Swissboy,

I also looked at your images carefully. I do not think that your ZEISS VICTORY FL 8x32 is faulty in any respect (maybe different from older versions though). Why do I come to that conclusion?

1. The LOTUTEC coating is almost colourless. The same is with other similar coatings, as their purpose is not to act as straylight-reducing anti- reflexion layer.
2. What was depicted just displays the interaction of the images of different lens surfaces reflexions with the coating layers that are close to each other and exposed to the observer: The outer antireflex- coating on the first exposed outer eyepiece lens interacts especially with the reflected light coming from the coated surfaces of some of the steeply curved lenses in the eyepiece. They are very close to each other. This you can control, if you illuminate the surface of the eyepiece with a homogeneous and diffuse light source (not looking at it outside) in an otherwise dark room. A tilt of the binocular will most likely show an even colour on the outer lens surface.
3. My SWAROVSKI EL´s show similar phenomena.
4. My KOWA TE 11 WZ eyepiece does show this even more extremely.
5. Makers of alpha binoculars do improve the coatings from time to time. ZEISS does and all the others too. That will most likely explain the difference in why the loan bino looks different from outside.

Only, if under normal observation conditions optical issues, e.g. orange spots etc. occur, even when the observer wears a hat, this would indicate a problem.

Maybe I am wrong, just my thoughts. Optics are made to look through them, not at them :)

Thanks
Michael

Last edited by Apochromat : Sunday 7th July 2019 at 12:24.
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Old Monday 8th July 2019, 20:51   #16
Swissboy
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Quote:
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Dear Swissboy,

I also looked at your images carefully. I do not think that your ZEISS VICTORY FL 8x32 is faulty in any respect (maybe different from older versions though). Why do I come to that conclusion?

1. The LOTUTEC coating is almost colourless. The same is with other similar coatings, as their purpose is not to act as straylight-reducing anti- reflexion layer.
2. What was depicted just displays the interaction of the images of different lens surfaces reflexions with the coating layers that are close to each other and exposed to the observer: The outer antireflex- coating on the first exposed outer eyepiece lens interacts especially with the reflected light coming from the coated surfaces of some of the steeply curved lenses in the eyepiece. They are very close to each other. This you can control, if you illuminate the surface of the eyepiece with a homogeneous and diffuse light source (not looking at it outside) in an otherwise dark room. A tilt of the binocular will most likely show an even colour on the outer lens surface.
3. My SWAROVSKI EL´s show similar phenomena.
4. My KOWA TE 11 WZ eyepiece does show this even more extremely.
5. Makers of alpha binoculars do improve the coatings from time to time. ZEISS does and all the others too. That will most likely explain the difference in why the loan bino looks different from outside.

Only, if under normal observation conditions optical issues, e.g. orange spots etc. occur, even when the observer wears a hat, this would indicate a problem.

Maybe I am wrong, just my thoughts. Optics are made to look through them, not at them :)

Thanks
Michael
Michael, thanks for your input. I fully agree with your last sentence! The problem is that before one can look through the binoculars, one has to bring them to the eyes. And if you get a reddish-orange flash into your eyes while doing so, it is definitely irritating. Fortunately this only happens under some specific conditions, as I outlined earlier.

There is, by the way, a reason for the question mark in the title of this thread. I was not sure whether the irritation actually comes from the Lotutec finish. I have by now learned that Lotutec is colorless, or at least that's what I take from all the posts here. So it's not Lotutec that causes the irritation, but it comes from the red coating underneath it. The irritation remains the same, though. Earlier Zeiss coatings are definitely preferable then. My own older 8x42 FL is - fortunately - equipped that way.
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What's your species on the avatar? I often have no clue
!

Last edited by Swissboy : Monday 8th July 2019 at 20:55.
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