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11-13-2017, 10:13 PM   #1
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Is this dust or fungus?

I just bought a lens, gave it the “flashlight test” and saw it’s got particles inside.
It’s slightly larger particles than one of my other dusty lenses.

I was wondering does it look like dust or fungus to you guys?

The streaking is from me starting to clean it , and the larger white things at 2:00 are smudges.

Macro Photo of the rear element. 1:1

11-13-2017, 10:15 PM   #2
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Possibly a bit of both. That hazy area near the center could be fungus. Could you try shooting the lens at a sideways angle?

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11-13-2017, 11:08 PM   #3
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I see haze. Even if it is dust, that is a lot of dust.
11-13-2017, 11:27 PM   #4
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The darker rings around the spots make it look like beginning fungus to me. It is the beginning of something really bad. I have seen it before. Clean it now.

11-13-2017, 11:28 PM   #5
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There's no hazing, the areas between spots are clear it's just the way the light shows up in the photos (at least that's how it looks looking through a loop).
The rear element is recessed 3/4 of an inch so I can't really get an angled shot of it.

Here I've got some more shots of it.

11-13-2017, 11:44 PM   #6
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The stuff in the middle looks like fungus - the fractal thing growing out from a central point - It's kinda pretty when it's on somebody else's lens
11-14-2017, 04:26 AM - 1 Like   #7

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My impression is that it is dust due to the particle edges appearing particularly clean and sharp (3rd image Post #5) - but that is one hell of an amount of dust (if that is what it really is where has the lens been - in a war zone?).

With fungus I would expect the spots to be more 'fuzzy' and have the beginnings of spreading fibrils (mycelium?) but it may be early stage.

I take it the particles are inside the lens therefore you cannot reach them?

In any event if the lens was mine I would be looking to have it inspected and cleaned by an expert in this field rather than rely on what I or anyone else may think it is even if it does not appear to affect IQ
11-14-2017, 05:14 AM   #8
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If the seller described it as clean you could request a refund because that is not a normal amount of dust. Whether you want to keep it and try fixing it yourself depends on what lens it is and how much you paid for it. It might be as simple as removing the front element and blowing it off or rinsing it in distilled water. If it's the beginnings of fungus between two lenses in a fixed group it would take an expert to clean.

What lens is it? If it's one you only plan to use wide open you might do just fine since the spots shouldn't show up until smaller apertures. (You might notice slightly more fuzziness, flare, or aberrations, but it might not be that bad.) If you decide to keep it, I would definitely recommend storing it someplace dry to prevent growth if it is fungus. The cheapest method is to put it in a ziploc freezer bag with some desiccant packs.

11-14-2017, 09:34 PM   #9
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Thanks everyone for your thoughts on it.
I think everyone's in agreement its bad.

I'm not going to let it near my K70 or other lenses.

It's a Tamron/promaster AF zoom lens, which I got for $18, not worth having someone clean it.

I learned an important lesson Always have the seller check for fungus.
I thought what were the chances of fungus? Well I got “lucky”.

Anyone want to buy an Uncle Miltons fungus farm? lol

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