[CaptureTheLight]

Hey,

Curious about what could be causing this hairline looking thing in each of the balls? Im assuming it would be something with one of the aperture blades? Please excuse the dirty sensor......

Thanks,
Chris

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[Digitalis]

There is either some hair or oil on one of the lens elements, it is also possible there could be some edge separation. You will need to take the lens apart to asses the nature of the problem, but it won't show up in images unless they contain highlights like this.

[CaptureTheLight]

That was my initial thought as well. I took all the elements out and inspected and cleaned. Did not see anything, and no change at all after cleaning. Im stumped. Optics appear perfect to the eye, and even under magnification I cant seem to find the culprit.

[Digitalis]

Aperture blades would cast a shadow, which would visibly disrupt the shape of the highlights in the photogaph. It isn't any mechanical fault here, what we are seeing is optical in nature. I would suggest examining the lens under cross polarised light: Put a polariser on the front of the lens, shine a light source through the front lens while looking through the rear of lens with a polariser over your eye* - this technique can reveal flaws in glass that would be difficult to observe without specialized equipment.


This might reveal the cause of your problems.



*turn the polarizer over your eye to 90° opposing the one on the lens - this will maximize contrast.

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Last edited by Digitalis; 11-28-2018 at 09:01 PM.

[stevebrot]

Reflection off the edge of the aperture blade?


Steve

[CaptureTheLight]

Sounds like i know how Im spending my evening!

Thanks,
Chris

Aperture blades would cast a shadow, which would visibly disrupt the shape of the highlights in the photogaph. It isn't any mechanical fault here, what we are seeing is optical in nature. I would suggest examining the lens under cross polarised light: Put a polariser on the front of the lens, shine a light source through the front lens while looking through the rear of lens with a polariser over your eye* - this technique can reveal flaws in glass that would be difficult to observe without specialized equipment.


This might reveal the cause of your problems.



*turn the polarizer over your eye to 90° opposing the one on the lens - this will maximize contrast.

[CaptureTheLight]

Went after it with magnifying lenses, polarized filter, and my lighting rig for fiber optic cleaning. Spent a good hour searching and cleaning. Failure. Never found anything to clean off and the cleaning i did had no effect on the issue.

Its a pretty extreme situation that creates it, doubtful that I would ever see it unless I did it intentionally.

[Wheatfield]

I'm pretty sure that is element separation.

[CaptureTheLight]

I'm pretty sure that is element separation.

That is interesting. So the groups that are fixed may have slight separation. Not something i checked. Back to the bench tonight to see if there us any evidence.

Thanks

[stevebrot]

That is interesting. So the groups that are fixed may have slight separation. Not something i checked. Back to the bench tonight to see if there us any evidence.

Thanks

This will usually show on close inspection with a small flashlight shown through the lens in a dim room and magnification using a loupe. Shining the light obliquely will illuminate the margins and bring subtle stuff into sharper relief.


Steve

[CaptureTheLight]

I suppose I going with the separation theory. If I shine a light in from the side of the front of the lens I do see some very small almost reflective areas that seem like they could be the edges of the element. Not very sure, but it seems like I can only cause a negative affect if I very deliberately try to do so. This is cell phone pic of what I think looks odd at the sides of the element. And then an image taken in the woods today just because.