19 replies to this topic

[a.palfreyman]

I've been repairing a pair of 8x30 Jenoptems and found that I was getting a 'halo flare' around the bottom on the image.
I think it's from the VERY shiny black plastic shroud at the back of the objectives:

Is there a way to remove this shroud (without completely dismantling the cell) as it certainly won't come out of the rear of the cell?

[Inkie]

If Zeiss put the shroud there, it was for an engineered purpose.  I don't dispute your findings, but I don't see that the cure is to remove the item.  Instead, could you see your way toward improving it?  You can buy specialty ultra-black, non-reflective paints, almost like powders, that can be swiped into place, allowed to cure, give it a light tap to see what, if anything, is willing to fall out again, and if it looks clean, reinstall the item and enjoy the flare-less views.

[a.palfreyman]

I hoped to remove and sand it internally, but paint may be the easiest solution. I have some matt black wood burner paint. I'll give it a try and hope it doesn't melt the plastic...

Edited by a.palfreyman, 22 March 2025 - 05:47 PM.

[pat in los angeles basin]

here's a thought to test without having to redo it, a wrap of thin flat black paper tucked into the area to test the theory that the bright ring is indeed the cause of the flare! If you can remove the objective or tuck it in from the small side?

[Rich V.]

That's clearly a very shiny "baffle tube".  Do those fine baffles fade away approaching the lens or is it just focus blur I see?  It sure looks like a perfect specimen to receive a coating of ultra flat black paint on its surfaces, if only you could detach it from the lens cell to get in there.     It may not be the absolutely most elegant solution but it sure can help on glare, and it's easy.

 

I've used UFB spray paint to dull the sharp anodized baffle edges that were throwing up some glare when pointed anywhere around the Moon.  UFB paint took care of the glare.  Anything shiny has to go!

 

I hope you find a way to remove the baffle to work on it.

 

[a.palfreyman]

No, it's ribbed all the way. Camera focus / 'white-out' issue.
I'll try a piece of paper blackened with a marker to be certain. Pat was right again.. ;-)

[RichA]

I've been repairing a pair of 8x30 Jenoptems and found that I was getting a 'halo flare' around the bottom on the image.
I think it's from the VERY shiny black plastic shroud at the back of the objectives:

Is there a way to remove this shroud (without completely dismantling the cell) as it certainly won't come out of the rear of the cell?

Take a black surface, shine a light at it and slowing decrease the angle of reflection with a photometer behind it.  Even a flat black surface can reflect a major percentage of the light.  But the other poster is right, some kind of better blackening would help.  Worst thing I ever saw was a 1-1/4" extension tube that was bright anodized inside.

[a.palfreyman]

With blackened paper cone inserted.

Not perfect, but a marked improvement.

[pat in los angeles basin]

Boy, you are quick on the fix!!   Regards, Pat

[pat in los angeles basin]

Out of curiosity, I took a 7x50 MK41 widefield bino that has prisms covers but no work on the inside of the objective tubes at all , took it out and aimed close to the sun (yes , I do know  what can happen to my eyes , thanks) and basically did a complete circle around the sun trying to induce glare. Outside of the usual  veiling glare I get from the single coatings, no rays or other bright intrusion in the optics. For a bino without any knife edge baffling it does a commendable job of keeping glare off at least in the daylight. As to a full moon I will have to wait a while for that test. Pat

[a.palfreyman]

I sanded inside one of the tubes after removing the objective as the eccentrics were 'frozen' so needed to come out anyway. Didn't work.
However, placing the binos in a 'tough light' situation give this:

Not as reflective, but just as strongly lit.

I have ordered a small bottle of Stuart Semple 'Black3', arriving at the W/E.
Hope this does it, but it also seems eye position / eye relief (specs wearer) plays a role too.

Edited by a.palfreyman, 24 March 2025 - 10:47 AM.

[pat in los angeles basin]

While you are waiting for the paint, try a simple objective lens hood extended out to shield the objective from straylight entering from an angle on the objectives. The lens is forward, close to the end of the tube- far too easy for light to hit the objective at an angle. I can't tell from the pics but there's also the ability to blacken the edge of the objectives to cut down on the impact of stray light.  Pat

[a.palfreyman]

Cheers Pat,
A hand held to 'shade' the objective cures it.
It's also apparent (but to a lesser extent) from a bright sky with dark foreground, away from direct sunlight.
I'll do both 'cones' and see how we go.

[pat in los angeles basin]

That's a cheap and reproduceable fix for glare control- usually not pretty but functional. As to the stuck retaining ring- a lens spanner, and some penetrating wicking oil along the ring and thread interface , allowed to work a while. Perhaps in the noonday sun to accelerate the wicking action, might aid in getting the stubborn ring.  Pat

[a.palfreyman]

Tubes painted:

Unfortunately, made B-all difference. :-(
More 'shade' testing shows it's light hitting the edge of the objectives causing the flare.
It seems that there is nothing that can be done as the objective can't be removed from the cell:

Shame really but there you go.

[pat in los angeles basin]

To be clear, the retaining ring simply can't be moved? Honestly, I'd expect from my very limited experience first hand with Euro optics that the edge would be blackened already?    Pat

[a.palfreyman]

I didn't give it the closest inspection but it looks as though 'formed/pressed' around the back outer edge that is shiny in above image. No retaining ring as such nor slots.

[pat in los angeles basin]

 post #11 shows the objective as retained with a two dog engagement. I see the dogs have been used before, are there any grubs around the edge of the objective lugs that might lock the ring in place, loosening the grubs may allow that dogged ring to move with the proper tool?  Pat

[JoeFaz]

What does the exit pupil look like? Is there by any chance a bright false pupil close to it, particularly underneath it (a partial EP outside of the main EP but fairly close to it? That would explain the eye placement sensitivity of the issue --- i.e., the view's fine if it doesn't enter your eye, but if the false pupil does reach your retina you get a "glare."

[a.palfreyman]

WRT the lens cells, there is an outer locking ring with two notches. Behind, there is a silver outer eccentric ring with two notches (@ 90 degrees to the thinner/ thicker portions) and inside this, there is the inner eccentric which is part of the lens cell that has a single notch at the thickest part of the eccentric. No sign of how to remove the lens from the cell.
WRT the exit pupils, there isn't a 'false' exit pupil that I'm aware of but will double-check.
Whilst facing the sun, if you slowly shade the cone behind the lens cell, there is a gradual slight improvement. When the shade crosses the edge of the lens cell, the flare almost completely disappears. So, it must either be the ground edge of the lens, or the cell wall. I suspect it's more likely the lens edge, but can't get to it to blacken it.