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08-06-2009, 12:50 PM   #1
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Sigma APO DG 70-200 mm Macro HSM

I have a problem regarding this lens. I bought it around 2 months ago and for almost a month was on the camera. It was in a LowePro bag so I do not think that was a problem with high humidity. Until today I didn't realize it but it seems that the first lens has something like a mold or uneven coating layer. I am sure that when I bought it, this was not there. Please help me with your oppinion regarding the possible cause. It is still in warranty, so I should take it to the store. I attached some images for better understanding of what's about.

Thank you.

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08-06-2009, 02:00 PM   #2
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It looks similar to my 50-135mm f/2.8....
I suggest sending it to Sigma repair center, although it might cost you if you are not in warranty.
08-06-2009, 02:01 PM   #3
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I don't have exactly the same "problem" as you do, but I also noticed an area inside the front element that seems to have spots on it, like if one had misted the lens with hard water. It covers roughly a circle with a diameter somewhat smaller than the actual lens. Doesn't seem to be fungus.

I don't know if it needs to be sent in, but I don't think I have any IQ issues from it so I haven't.
08-06-2009, 02:05 PM   #4
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If in doubt, get it checked out.
Does look like a problem that will just get worse if left alone.
If it doesn't look like fungus, it might be haze, though I don't suppose you'd cleaned it with any cleaning agents some time ago...

08-06-2009, 09:58 PM   #5
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Thanks for answers. If there is no fungus also I will not worry too much. I am only afraid not to spread and to destroy all the coating (if it's the case).

Thanks again for the help.
08-07-2009, 10:27 AM   #6
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QuoteOriginally posted by krypticide Quote
I don't have exactly the same "problem" as you do, but I also noticed an area inside the front element that seems to have spots on it, like if one had misted the lens with hard water. It covers roughly a circle with a diameter somewhat smaller than the actual lens. Doesn't seem to be fungus.

I don't know if it needs to be sent in, but I don't think I have any IQ issues from it so I haven't.
Mine has the same thing as what you described. I haven't noticed any IQ issues and have plenty of warranty left if it decides to change and get worse. It is my only Sigma lens and the only lens that has this appearance.

To the OP, I'd send it in if mine looked like that and see what the experts say.
08-07-2009, 11:26 AM   #7
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QuoteOriginally posted by krypticide Quote
I don't have exactly the same "problem" as you do, but I also noticed an area inside the front element that seems to have spots on it, like if one had misted the lens with hard water. It covers roughly a circle with a diameter somewhat smaller than the actual lens. Doesn't seem to be fungus.
That's interesting. Is it on the INSIDE of the front element?

I have a Sigma 24-60mm lens with something that sounds almost identical to what you describe. Lots of tiny little spots on the coating (maybe pin-head sized), more or less circular if you look closely, that don't come off with a cloth or lenspen. I was thinking the coating might be flaking off. I have treated this lens very carefully, so I don't think it's anything I did physically.

But they do almost look like water spots.

My spots are on the outside of the front element. I'll see if I can get a photo that shows them.
08-07-2009, 11:42 AM   #8
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lens element separation

It looks to me like lens element separation.

I just checked the Sigma website, and sure enough the front "element" is actually a group of two elements (which are glued together). When the bonding gives way, it looks just like the photos you posted. Your front elements are separating. I would send it in for repair or replacement.

Dan

08-07-2009, 12:24 PM   #9
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QuoteOriginally posted by Dan Quote
It looks to me like lens element separation.

I just checked the Sigma website, and sure enough the front "element" is actually a group of two elements (which are glued together). When the bonding gives way, it looks just like the photos you posted. Your front elements are separating. I would send it in for repair or replacement.

Dan
I would agree with the above. I have a 70-200mm HSM II and it is pefectly clear. For the previous post, I have a 24-60mm which is also clear. I would have it repiar immediately.
08-07-2009, 05:14 PM   #10
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QuoteOriginally posted by Dan Quote
It looks to me like lens element separation.

I just checked the Sigma website, and sure enough the front "element" is actually a group of two elements (which are glued together). When the bonding gives way, it looks just like the photos you posted. Your front elements are separating. I would send it in for repair or replacement.

Dan
Could you point to where on the website you saw this info? Thanks!
08-07-2009, 11:17 PM   #11
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QuoteOriginally posted by Dan Quote
It looks to me like lens element separation.

I just checked the Sigma website, and sure enough the front "element" is actually a group of two elements (which are glued together). When the bonding gives way, it looks just like the photos you posted. Your front elements are separating. I would send it in for repair or replacement.

Dan
I could see how that looks like a elements separating, this has me really worrying about mine now.

I looked at mine closely again. I could only see the "spots" if I held the lens at a specific angle to the light. If looking at it either straight on or at a significant angle, the lens looked clear, the spots were only visible at a slight angle. Like others have said, my spots look like hard water almost. Pinpoint size spots 1-2 mm apart from eachother throughout the entire lens and not on the outer surface.
08-08-2009, 06:20 AM   #12
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QuoteOriginally posted by krypticide Quote
Could you point to where on the website you saw this info? Thanks!
Here it is:

Sigma - Lenses

This is actually the website for the previous version. The website for latest version is missing the lens construction diagram. Both the previous version and the newest version contain 18 Elements in 15 Groups, so it seems likely that they share a similar (or perhaps identical) optical design.

Dan
08-08-2009, 11:30 AM   #13
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Ah, I see, so the element separation was something you inferred or experienced, not information directly stated on the website.

Has anyone bothered to call Sigma and ask about the small spots?
08-08-2009, 03:22 PM   #14
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Nope, probably would be a lot smarter than what sounds like several of us with a potential issue speculating about it.
08-08-2009, 04:22 PM   #15
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QuoteOriginally posted by picatalin Quote
Thanks for answers. If there is no fungus also I will not worry too much. I am only afraid not to spread and to destroy all the coating (if it's the case).

Thanks again for the help.
I actually noticed that if you put the lens in a bag of rice or silicone gel, it will go away.
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