Lens Haze...

[tgtaylor]

What is it and how do you get rid of it?

Today I was dismayed to find a light brownish looking haze beginning to cover the lens element cloud-like when viewed with a flashlight. There was a more ominous-looking broken ring at the very edge if the element where it meets the barrel but I couldn't determine if it was fungus or lens cleaner residue that had settled there from a previous cleaning. I separated the front and rear elements from the shutter and using Promaster Optic Clean, Olympic lens tissues, a microfiber lens cloth and condensation from my breath was able to clean the haze and residue from the elements. When not in use I store this lens in a Pelican waterproof case. No other lens stored in the same case exhibited a haze.

Was the haze the beginning of a fungal infection on the lens or something else?

Thomas

[Sirius Glass]

Put the lens, and other lenses, in the sun so that the light travels though the lens. That can get rid of some problems.

[Kiwi7475]

I could be wrong but I don’t think hazing is that well understood. It seems it could be from vaporization of coatings, lubricants and alike inside the lens and depositing on the glass. Or it could be from micro condensation/oxidation.

I don’t have personal experience but some claim it can be cleaned to some extent with standard cleaning solutions for lenses (an area where most people have their own opinion) but you have to open/disassemble the glass layers that may be affected.

Friends of mine in the past had John van Stelten from Focal Point do the cleaning quite effectively but alas he’s no longer in business. I am not aware of others that do this work but there may be.

Note this is different from fungus— but you know that.

[Nodda Duma]

There are two primary sources of haze:

1) outgassing of volatiles from within the assembly (ie lubricants but not coatings..coatings do not dissipate). Typically the source of haze on internal surfaces. Everyday example is haze on the inside of your windshield. This can be cleaned off.

B) micro-erosion of coatings due to condensation. Some of the materials used for AR coatings are slightly soluble in water, especially if alkaline (sea air) or acidic (acid rain). Requires special coatings if designing optics for naval use. :) This haze is physical damage that cannot be repaired, and is of course most often found on the front external surface. If it doesn’t clean off with the usual suite of solvents then your lens has this issue. Use a protective filter and/or live with it.

Consequences of haze are, of course, reduced contrast, increased flaring, and “glow” at edges of bright objects on dark background.

[Nodda Duma]

There are two primary sources of haze:

1) outgassing of volatiles from within the assembly (ie lubricants but not coatings..coatings do not dissipate). Typically the source of haze on internal surfaces. Everyday example is haze on the inside of your windshield. This can be cleaned off.

B) micro-erosion of coatings due to condensation. Some of the materials used for AR coatings are slightly soluble in water, especially if alkaline (sea air) or acidic (acid rain). Requires special coatings if designing optics for naval use. :) This haze is physical damage that cannot be repaired, and is of course most often found on the front external surface. If it doesn’t clean off with the usual suite of solvents then your lens has this issue. Use a protective filter and/or live with it.

Consequences of haze are, of course, reduced contrast, increased flaring, and “glow” at edges of bright objects on dark background.

[govindvkumar]

If the place you are living has high humidity then this problem can occur I guess.
So, a dry cabinet is a good solution.
Otherwise keep the lens inside a thermocol box with an Incandascent bulb switched on inside for heating.

[Mark Sawyer]

Purple haze, all in my lens,
Gonna sell it to my eBay friends.
Don't return it, don't even try,
I said "as is", that's my alibi...

Oh great, that's gonna be in my head all night...

[LabRat]

Another potential problem is simply the atmospheric pressure changes all the time and higher pressure + humidity can work it's way into weather resistant items, but have trouble leaving, so it leaves some moisture inside which later can cause issues... (Old, uncoated lenses get calcium haze inside from this) And this condition can harbor fungus growth...

Cases, bags, storage often will take in moisture, but if waterproof will hold in that moisture...

Gear should be aired out in storage, and a low to medium humidity, but constantly too high and materials can haze, etch, attract growth, corrode even under moderate high conditions...

At least try to store stuff where it can breathe, and not store pieces in a too confined space unless some fresh silica gel is used... And avoid storing in foam or some plastics, as this can outgas and coat other materials damaging them over the long term...

Steve K

[EdSawyer]

There's also de-vitrification, where some elements in the glass mix decompose and rise to the surface of the glass. Can't be cured except by repolishing, which removes any coatings and may mess up the lens curvature/formula.

[Bob Salomon]

There's also de-vitrification, where some elements in the glass mix decompose and rise to the surface of the glass. Can't be cured except by repolishing, which removes any coatings and may mess up the lens curvature/formula.

Most of my career I worked for a company owned by Gepe, the worlds largest producer of glass and glass less slide mounts. A fairly common problem with glass mounts, after extended time, was a white deposit that would migrate through the glass to the top surface. Fortunately this deposit would easily wipe off with a soft cloth.

Or if unused mounts they could be cleaned in a dishwasher if you had a rack to hold them.