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jack56 · 07-29-2009, 08:46 PM

I have a chance to get a Sigma APO 400mm f5.6 Telephoto Lens Cheap.
The catch is can this lens glass that is foggy between the elements be fixed?

Can it be taken apart or maybe put the lens in a case with desiccant, so it will absorb any moisture that may be inside of the lens?

creampuff · 07-30-2009, 05:39 AM

This is an issue with Sigma lenses... fogging elements... the value of the lens has just gone down to junk... just no way to rectify the problem. Save your money and give this a miss...

jack56 · 07-30-2009, 08:42 AM

Originally posted by creampuff

This is an issue with Sigma lenses... fogging elements... the value of the lens has just gone down to junk... just no way to rectify the problem. Save your money and give this a miss...

So there is no way to take apart the lens to clean and defog it?

**pentaxman** · 07-30-2009, 09:50 AM

Originally posted by jack56

So there is no way to take apart the lens to clean and defog it?

This is an issue with this particular lens. I bought one used and had to return it because of fogging of the internal lens elements. It is also not that great a lens even when it isn't fogged (unless it is the Macro version). The one I purchased looked like the fogging was in a group of elements in the center of the lens which would require complete diassembly. The fogging is probably in the cement between the elements which cannot be easily repaired. I would stay far away.

**Just1MoreDave** · 07-30-2009, 09:58 AM

I think the problem is element separation. Two lenses are glued together and the glue is failing. The repair is to get the lenses apart, clean off the old glue, reglue them and reassemble. I've only read about it, and it sounds like skydiving - better to get it right the first time.

I've also read various recommendations for glue, including not bothering with glue and using mineral oil instead.

ivoire · 07-30-2009, 10:09 AM

Avoid this one. If you can find a good copy of the Sigma 400mm f5.6 APO Macro version then let go of your cash as its the best of their 400mm lenses and is very good in both the manual and auto focus versions.

jack56 · 07-30-2009, 11:16 AM

OK then, I'll pass up this one. I could get it for $50 and had figured I'd gamble on taking it apart to repair. But it sounds like a lot of work...

07-29-2009, 08:46 PM	#1
jack56 Senior Member Join Date: Apr 2009 Location: Tacoma, WA Photos: Gallery Posts: 119	Sigma APO 400mm f5.6 Telephoto Lens that is foggy I have a chance to get a Sigma APO 400mm f5.6 Telephoto Lens Cheap. The catch is can this lens glass that is foggy between the elements be fixed? Can it be taken apart or maybe put the lens in a case with desiccant, so it will absorb any moisture that may be inside of the lens?

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07-30-2009, 05:39 AM	#2
creampuff Veteran Member Join Date: May 2007 Location: Singapore Photos: Gallery Posts: 3,953	This is an issue with Sigma lenses... fogging elements... the value of the lens has just gone down to junk... just no way to rectify the problem. Save your money and give this a miss...

07-30-2009, 08:42 AM	#3
jack56 Senior Member Join Date: Apr 2009 Location: Tacoma, WA Photos: Gallery Posts: 119 Original Poster	Originally posted by creampuff This is an issue with Sigma lenses... fogging elements... the value of the lens has just gone down to junk... just no way to rectify the problem. Save your money and give this a miss... So there is no way to take apart the lens to clean and defog it?

07-30-2009, 09:50 AM	#4
pentaxman Site Supporter Join Date: Oct 2007 Location: Washington Photos: Gallery Posts: 250	Originally posted by jack56 So there is no way to take apart the lens to clean and defog it? This is an issue with this particular lens. I bought one used and had to return it because of fogging of the internal lens elements. It is also not that great a lens even when it isn't fogged (unless it is the Macro version). The one I purchased looked like the fogging was in a group of elements in the center of the lens which would require complete diassembly. The fogging is probably in the cement between the elements which cannot be easily repaired. I would stay far away.

07-30-2009, 09:58 AM	#5
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	I think the problem is element separation. Two lenses are glued together and the glue is failing. The repair is to get the lenses apart, clean off the old glue, reglue them and reassemble. I've only read about it, and it sounds like skydiving - better to get it right the first time. I've also read various recommendations for glue, including not bothering with glue and using mineral oil instead.

07-30-2009, 10:09 AM	#6
ivoire Veteran Member Join Date: Mar 2007 Photos: Gallery Posts: 3,381	Avoid this one. If you can find a good copy of the Sigma 400mm f5.6 APO Macro version then let go of your cash as its the best of their 400mm lenses and is very good in both the manual and auto focus versions.

07-30-2009, 11:16 AM	#7
jack56 Senior Member Join Date: Apr 2009 Location: Tacoma, WA Photos: Gallery Posts: 119 Original Poster	OK then, I'll pass up this one. I could get it for $50 and had figured I'd gamble on taking it apart to repair. But it sounds like a lot of work...

Sigma APO 400mm f5.6 Telephoto Lens that is foggy

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