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Swarovski CL 10x30 - opinions?

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Old Monday 16th December 2019, 15:15   #26
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I come from photography. In the field of cinema and professional photography, it is forbidden opening the shutter before having positioned the appropriate hoods on the lens. It seems that this natural and logical system, which rightly follows the laws of optical physics, is totally ignored by both producers and users of binoculars.
At the beginning of the last century, binoculars were often equipped with removable lens hoods. Even today, only a few super astronomical or long-range binoculars, have the hoods. In the panorama of aiming optics, on the other hand, each model has optional hoods and various ARDs.
https://i.ebayimg.com/images/g/qPkAA...jL/s-l1600.jpg

2 or 3 mm of lens hood does not make the difference (a length at least equal to the diameter of the lens will be needed).
The Nikon with its 30mm Monarch7 did a flop, with side flares. And not even the use of a suitable lens hood could solve the situation.

But many binoculars with these defects, can be solved perfectly with just the shadow of the hand or the visor of a hat as a lens hood. And therefore, to deprive yourself of an excellent instrument that has some flares, is in my opinion an anti-logical procedure.

How many times have I read about people who gave up fantastic binoculars, for this problem that can often be solved with little.
I bet if more binoculars came with lens hoods like you show the glare would be vastly improved.

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Old Monday 16th December 2019, 17:43   #27
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Sure, Dennis. Many binoculars improve with the hoods. But even the hood must be adequate and well designed, to solve 100% or so. When I started, I had taken and returned a 10x25 Trinovid. I was amazed that it had more glow than a cheap Celestron Nature DX 10x25. But not even Leica provided lens hoods to solve.

Then I realized that glows from side lights can be solved, while ghosts cannot. Binoculars that have internal ghosts degrade the vision and nobody can do anything. There is no lens hood to help them. The Trinovid was transparent and neutral even at night, in front of the moon. Many other binoculars, no.
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Old Monday 16th December 2019, 23:11   #28
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Hi Tenex. Could be. But Dennis was talking about "SV 10x32 vs all the other SVs (42-50mm)"
Then it is your own remark (which I was addressing, not Dennis) that becomes difficult to understand:
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In this case, I believe that it is the very wide field of view that creates reflex and glare problems.
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Old Tuesday 17th December 2019, 12:44   #29
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Then it is your own remark (which I was addressing, not Dennis) that becomes difficult to understand:
Simply, as I wrote (I hope there are no errors in the translation - I use google translate).
In general, the cause of the glare is more often attributable to the very wide field of view, rather than to the narrow exit pupil.
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Old Tuesday 17th December 2019, 14:22   #30
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Back in the 80's I used a trusty pair of 10x50 Jenoptem with a 15cm length of plastic drainpipe of an appropriate diameter, split down one side and pushed over each barrel from the objective end, in order to control glare/flaring. It worked a treat.

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Old Tuesday 17th December 2019, 14:42   #31
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Hi Rico,

While I agree it's true that small exit pupils don't cause glare they do allow glare causing internal reflections near the edge of the exit pupil to enter the pupil of the eye more readily than when the same internal reflections occur near the edge of a large exit pupil.

Dennis, reasonably sized hoods have limited usefulness for most glare problems in binoculars because the typical angle of glare producing light is in the range of 20-30 off the optical axis. That means the length of the hood needs to be more than twice the diameter of the objective lens to fully shade the lower part of the objective lens cell (the usual culprit) from glare producing light. It's far more effective to place a knife edged baffle or shallow baffling cone close behind the objective cell.

Henry
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Old Tuesday 17th December 2019, 15:52   #32
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Hi Rico,

While I agree it's true that small exit pupils don't cause glare they do allow glare causing internal reflections near the edge of the exit pupil to enter the pupil of the eye more readily than when the same internal reflections occur near the edge of a large exit pupil.

Dennis, reasonably sized hoods have limited usefulness for most glare problems in binoculars because the typical angle of glare producing light is in the range of 20-30 off the optical axis. That means the length of the hood needs to be more than twice the diameter of the objective lens to fully shade the lower part of the objective lens cell (the usual culprit) from glare producing light. It's far more effective to place a knife edged baffle or shallow baffling cone close behind the objective cell.

Henry
So you would need a long one to be of any benefit. They use lens hood's on telescopes but they are quite long and a lot of their benefit is probably to keep the dew off. Also, cameras use lens hoods.

"Cause of lens flare
Flare occurs when stray light strikes the front element of a lens and then bounces around within the lens. This stray light often comes from very bright light sources, such as the Sun, bright studio lights, or a bright white background.[2] If a light source is in the lens' angle of view, a lens hood will hardly have any effect, but the light does not have to cause lens flare. It is sufficient that stray light from a bright light source enters the lens. Multi-layer coatings in newer lenses also help to reduce lens flare."



https://en.wikipedia.org/wiki/Lens_hood
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Old Tuesday 17th December 2019, 17:02   #33
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The Wikipedia quote about the causes of lens flare applies mainly to camera lenses with wider fields than binoculars. Glare problems in binoculars are typically not caused by light falling on the glass of the objective lenses, but rather by light glancing off internal metal parts like the cells of objective or focusing lenses and occasionally an undersized prism edge.
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Old Tuesday 17th December 2019, 17:52   #34
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The Wikipedia quote about the causes of lens flare applies mainly to camera lenses with wider fields than binoculars. Glare problems in binoculars are typically not caused by light falling on the glass of the objective lenses, but rather by light glancing off internal metal parts like the cells of objective or focusing lenses and occasionally an undersized prism edge.
Henry. What about telescopes? Where does glare come from on them? Thanks.
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Old Tuesday 17th December 2019, 20:23   #35
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Well, binoculars are telescopes. The fundamental cause of glare in telescopes is non image forming light entering through the objective lens from an angle outside the FOV, then reflecting off some shiny interior surface at an angle that sends it back through the eyepiece and into the eye.

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Old Tuesday 17th December 2019, 21:11   #36
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While I agree it's true that small exit pupils don't cause glare they do allow glare causing internal reflections near the edge of the exit pupil to enter the pupil of the eye more readily than when the same internal reflections occur near the edge of a large exit pupil.
Hi Henry, I find myself a little embarrassed to argue or otherwise to discuss this. But I make an attempt on two distinct points.
1 - In fact I should point out that I have never written that "narrow pupils DO NOT cause glare". Indeed, for example, the Trinovid 10x25 is subject to glare, sometimes even more than other cheaper binoculars.
2 - This other thing you are saying is new to me and I never thought about it. In fact, if I think about it, I don't think I've ever been able to prove if it's as you say. It seems unlikely to me, as there are not two binoculars that are perfectly equal or in any case so well proportioned, one with a wide pupil and the other with a narrow pupil, with which it is possible to establish it. And every time I diaphragmed a pair of binoculars, I found quite the opposite.
But maybe I don't have enough experience in this regard. I had never even thought about it.

Thank you for your interventions, take care of Dennis for me

Last edited by Rico70 : Tuesday 17th December 2019 at 21:14.
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Old Wednesday 18th December 2019, 15:58   #37
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Hi Henry, I find myself a little embarrassed to argue or otherwise to discuss this. But I make an attempt on two distinct points.
1 - In fact I should point out that I have never written that "narrow pupils DO NOT cause glare". Indeed, for example, the Trinovid 10x25 is subject to glare, sometimes even more than other cheaper binoculars.
2 - This other thing you are saying is new to me and I never thought about it. In fact, if I think about it, I don't think I've ever been able to prove if it's as you say. It seems unlikely to me, as there are not two binoculars that are perfectly equal or in any case so well proportioned, one with a wide pupil and the other with a narrow pupil, with which it is possible to establish it. And every time I diaphragmed a pair of binoculars, I found quite the opposite.
But maybe I don't have enough experience in this regard. I had never even thought about it.

Thank you for your interventions, take care of Dennis for me
Hi Rico,

"In general, the cause of the glare is more often attributable to the very wide field of view, rather than to the narrow exit pupil."

I apologize if I misunderstood your meaning in the quote above.

As for point #2, I think you could make the observations you require with an instrument like a zoom binocular or a telescope with low and high magnification eyepieces. That would allow you to vary the size of the exit pupil without affecting the internal reflections that cause glare. But, I think a thought experiment might be all that's needed.

Imagine two binoculars, an 8x20 and an 8x56. Assume that in difficult lighting conditions both suffer from a bright reflection glancing off their objective lens cells and back through the eyepiece to the eye. In the 8x20 that reflection is at the edge of a 2.5mm exit pupil and in the 8x56 it's at the edge of a 7mm exit pupil. Now imagine that an observer's eye is dilated to 3mm. When the 2.5mm exit pupil is brought to the front surface of the eye at the eye relief distance it forms a focused image of objective lens and the bright reflection at its edge within the 3mm pupil of the eye, so the reflection enters the eye and the observer sees veiling glare. When the 7mm exit pupil is focused at the observer's eye in the same way the reflection at its edge falls outside the observer's 3mm pupil, so the reflection never enters the eye and no veiling glare in noticed.
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