Sigma 70-200 f2.8 II Lens Spots / Bubbles

Started Dec 9, 2010 | Discussions thread
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smaky
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Sigma 70-200 f2.8 II Lens Spots / Bubbles
Dec 9, 2010

Hello. Recently I purchased the lens mentioned in the post title. I've provided a link to a photo which shows some sort of bubble / spot phenomenon on the inside of the front element. So far two copies of this lens (serial number beginning 111) have had this issue.

Can anybody identify them? I realise the image isn't the best. In the flesh they appear as a flat spot rather than a bubble and are about the size of a pinprick. The image shows their location and density accurately. They appear in a 10mm band around the edge of the front element. There are larger spots, but they are much rarer.

I have searched around and found reference to the "problem" but so far I've not found out what the bubbles / spots actually are or if they're really a problem at all.

Cheers

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