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Red lens-coating irritation? (1 Viewer)

Swissboy

Sempach, Switzerland
Supporter
Switzerland
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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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.
 
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
 
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
 
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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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.
 
Thanks Robert and sorry to hear about this distraction. Hope it doesn't spoil your enjoyment too much.

Lee
 
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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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
 
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.
 
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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.
 
..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.
 
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.
 
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?
 
Coating Appearance in Natural Dayliight

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
 
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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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Has Lotutec been added together with the change in coating color?

………………... 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.

It seems, red coating is not usually mentioned specifically, whereas Lotutec may be. So my question is whether by inquiring about Lotutec, one also gets info about the coating color?

In other words, are there models that have the red coating (that irritates me at times), but do not have Lotutec? Or are there models that have Lotutec, but still have the less intensive color on the coating? (That would be my optimal version.)
 
It seems, red coating is not usually mentioned specifically, whereas Lotutec may be. So my question is whether by inquiring about Lotutec, one also gets info about the coating color?

In other words, are there models that have the red coating (that irritates me at times), but do not have Lotutec? Or are there models that have Lotutec, but still have the less intensive color on the coating? (That would be my optimal version.)

Robert:

It seems you are asking about the reflection color from the objective lens.
They come in all colors, and Zeiss often does reflect a bit red.

I am not sure why you are irritated, as what you see through the oculars
will be much different.

I find Zeiss to be quite neutral in color presentation, and they are very bright
and good in low light. Rest easy, Zeiss does know what they are doing.

There are other binoculars that reflect red.

Jerry
 

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Robert:

……..……...

I am not sure why you are irritated, as what you see through the oculars
will be much different.

……………..

Jerry

Jerry, if you look at my OP (post #1), you see what I mean. The reflection color - unfortunately - is not only on the objective side, it is also on the ocular side. I get some of that red at times when I'm having a bright background in my back, such as the sun shining from behind. The reason is that my eyeglasses which I have to wear while looking through any optics, are leaving a gap on the side. Thus when the sun shines in from the side, I get that red at the rim of my field of vision. Never had such problems with coatings that are less dominating in color. Among others, I have been using a Zeiss FL 8x42 since 2005, thus one of the types without that red coating.

I agree with you regarding the fabulous Zeiss view, that's why I do not want to move away from Zeiss. But that is also why I'm looking for older versions of FLs. They are the last ones without that red.

So to get back to your saying that "Zeiss know what they are doing", I think they missed an important element.
 
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Robert:

I still cannot see your problem, I suspect you have other binoculars. I don't wear glasses so your
issue includes your glasses.
In my opinion, the reflection coating color of any binocular is so slight, it should not make any difference at all
to the user.

Your questioning of this seems unusual, and I have not seen it mentioned before.

Jerry
 
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