Regular patterned marks/scratches on Retra LSD top glass

Hi all,

I purchased my Retra LSD last year and I only used it once, I carried it with protection bag, rinse it with clean water and stored in electronic dry box after use. But recently I found out there are many scratches/marks with regular pattern on the LSD top glass (please see attached photos).

At first I thought it was fungus/mildew growth inside the top glass, I contacted Retra and they ask me to send the LSD back for inspection. But after their inspection, they found out the scratches are on the glass surface and there's no mildew inside, they suggest that the scratches are formed probably by exposure to chemical substance and high heat, and charged me for the repairing and shipping fee which I think is reasonable if it's not manufacture or material problem.

But I doubt that the scratched/marks are formed by chemicals and heat, as I only used it for one time, I rinsed with clean water only afterwards and never expose it under sunlight for long time. And the marks pattern are so regular that I don't think it is formed by bumping with hard object.

Anyone have ideas on what's causing these marks or have similar experience? Please share your thoughts, sorry for the long essay and thanks a lot!

Looks like fungus to me...

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2 minutes ago, Timz said:

Looks like fungus to me...

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Yes I think so but Retra deny it after inspection and suggest its scratches on glass surface...

Yes I think so but Retra deny it after inspection and suggest its scratches on glass surface...

Just now, Timz said:

because the tube is completely sealed. pf course the fungus can only grow on the outer surface...

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That means they are right.. it may be scratches from unknown substance...but certainly not by chemicals or high heat...I have no idea..

I've had two lenses that bit the dust through fungus growth (living in Indonesia) and they didn't look like that. Much more of a mottled effect. 

Is it possible that sand has got in? Scratches from grains of sand?

But I don't they should have a major impact on the use of the LSD.(I've got one too)  Pity from a cosmetic viewpoint of course, but the LSD only shapes the light and I would not have thought scratches like that would make much difference?

20 minutes ago, TimG said:

I've had two lenses that bit the dust through fungus growth (living in Indonesia) and they didn't look like that. Much more of a mottled effect. 

Is it possible that sand has got in? Scratches from grains of sand?

But I don't they should have a major impact on the use of the LSD.(I've got one too)  Pity from a cosmetic viewpoint of course, but the LSD only shapes the light and I would not have thought scratches like that would make much difference?

yes I think it doesn't have major impact on the usage too but I have paid the high shipping cost anyway so I'd just let them repair it. I am not sure if grains of sand are able to produce such regular pattern but its a good suggestion... thanks