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09-01-2010, 07:33 PM   #1
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Should I buy this lens ? Possible defect...

Hello everyone, I don't post much here anymore (Nikon got me), but to be honest, I've gotten some of the most helpful responses here as opposed to the forums I now frequent.

I'm about to purchase a model of this lens, an older model, but came across a seller who fully disclosed a lens which seems to be in great functional condition, but has a small flaw on the front glass. I can't tell if its fungus, de-cementation (someone explain to me what this means, haha), lens separation, etc. I figure that many Pentax users have tons of legacy glass so someone must've seen something like this....

and closer:

Any insight is greatly appreciated!

And lastly, would you buy this lens at 70% of its typical used value? (Typically goes for $450, could probably get this for $300).

09-01-2010, 09:19 PM   #2
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That looks like a problem with the coating but should not affect the image.

Don't know if I'd buy it regardless, as you don't tell us what it is.
09-01-2010, 09:25 PM   #3
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It does not look like fungus to me, more like small separation of elements or coating problem. In either case it is going to affect images in any way, especially because it is so far away from the center.
09-01-2010, 09:46 PM   #4
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The lens is a Nikon 180mm f/2.8. They range in price from $900 for the newest D-version to 450-500 for a pristine copy of an older (just as good) non-D version. Forum prices typically range from 430-580. This seller would accept $300 for this copy, and says its very sharp. I'm just worried about future deterioration of the lens.

09-02-2010, 07:11 AM   #5
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any more input? I guess I'm just worried about the blemish potentially spreading to the point where it actually affects the images.
09-03-2010, 07:00 AM   #6
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I think it has a long way to go before it will start affecting results, and even then it will be just some loss of contrast, if anything.
09-04-2010, 02:25 AM   #7
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I always like to reference these pictures, they're from It shows how much u have to do to the lens for it to affect pictures.

The pictures:

The lens:
09-04-2010, 04:20 AM   #8
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can we believe that the cracked lens was really used to take those pictures?

09-04-2010, 04:56 AM   #9
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I would agree with Ataboy on this. The only issue is whether the separation between groups is a long or slow process. I just don't know.

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