Glue separation or Fungus?

Started Mar 28, 2006 | Discussions
chibitul smecher
Regular MemberPosts: 137
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Glue separation or Fungus?
Mar 28, 2006

I have a 28-70 f/4 which apparently has some issues with the glue between two elements coming loose causing them to separate and there seems to be an air gap in between these elements. When I look through the lens I see a light "haze" which covers maybe 30-40% of the area, and it does not seem to affect the picture quality. A potential buyer took it to a camera shop and those people said it looks like fungus, so the buyer backed up. Now I still have the lens and I wonder if I should try to clean it myself or sell it on eBay AS IS with a clear explanation that there is a "haze" and I am not sure of it's the glue or fungus.

QUESTION: how can I tell if it is glue separation of fungus????

Neal M
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Re: Glue separation or Fungus?
In reply to chibitul smecher, Mar 28, 2006

http://www.chem.helsinki.fi/~toomas/photo/fungus/

That link shows a pretty good picture of fungus, in line with what I have seen in person only not as bad. But as others have noted this particular lens has a history of separation problems...that might just be what it is. If it is separation I wouldn't think it is economically feasible to repair it.

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wlachan
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A common problem with this lens
In reply to chibitul smecher, Mar 28, 2006

And not worth fixing unless DIY.
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Alan Chan
http://www.pbase.com/wlachan/

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Joe Barnhart
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Re: Glue separation or Fungus?
In reply to chibitul smecher, Mar 28, 2006

If it is separation (and it seems likely) you can have it fixed by Pentax. I think I paid $75 plus shipping to have mine done. The separation looks like fog somewhere near the rear elements that never evaporates. It doesn't have the "tendrils" of fungus -- at least mine didn't.

Of course, $75-100 is a decent price for a copy of this lens, hence the comments about it not being economical. If you decide not to fix it, you might auction it with a clear description of its problem. I've seen folks buy this lens in exactly the same shape. And that's better than it winding up in landfill.

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Joe B.

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Anastigmat
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Re: Glue separation or Fungus?
In reply to chibitul smecher, Mar 28, 2006

chibitul smecher wrote:

I have a 28-70 f/4 which apparently has some issues with the glue
between two elements coming loose causing them to separate and
there seems to be an air gap in between these elements. When I look
through the lens I see a light "haze" which covers maybe 30-40% of
the area, and it does not seem to affect the picture quality. A
potential buyer took it to a camera shop and those people said it
looks like fungus, so the buyer backed up. Now I still have the
lens and I wonder if I should try to clean it myself or sell it on
eBay AS IS with a clear explanation that there is a "haze" and I
am not sure of it's the glue or fungus.

QUESTION: how can I tell if it is glue separation of fungus????

I once bought a lens that had what the seller described as lens separation. Upon disassembling it, I find that an internal lens surface is actually covered by a light coat of oil from the aperture blades. The aperture blades themselves are also soaked with oil. The glue that holds two lens elements together usually do not separate easily. Besides, even if the glue disintegrates, the two lenses are held tightly together in place at the edges of the barrel so they won't physically separate. If you have haze inside a lens, it could be because the oil from the blades have evaporated and redeposited on another lens surface. One way that can occur is when a lens is left inside the hot interior of a car, which can reach well over 130 degrees fahrenheit, and the oil inside a lens vaporizes.

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chibitul smecher
Regular MemberPosts: 137
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Re: Glue separation or Fungus?
In reply to Anastigmat, Mar 28, 2006

Anastigmat wrote:

chibitul smecher wrote:

I have a 28-70 f/4 which apparently has some issues with the glue
between two elements coming loose causing them to separate and
there seems to be an air gap in between these elements. When I look
through the lens I see a light "haze" which covers maybe 30-40% of
the area, and it does not seem to affect the picture quality. A
potential buyer took it to a camera shop and those people said it
looks like fungus, so the buyer backed up. Now I still have the
lens and I wonder if I should try to clean it myself or sell it on
eBay AS IS with a clear explanation that there is a "haze" and I
am not sure of it's the glue or fungus.

QUESTION: how can I tell if it is glue separation of fungus????

I once bought a lens that had what the seller described as lens
separation. Upon disassembling it, I find that an internal lens
surface is actually covered by a light coat of oil from the
aperture blades. The aperture blades themselves are also soaked
with oil. The glue that holds two lens elements together usually
do not separate easily. Besides, even if the glue disintegrates,
the two lenses are held tightly together in place at the edges of
the barrel so they won't physically separate. If you have haze
inside a lens, it could be because the oil from the blades have
evaporated and redeposited on another lens surface. One way that
can occur is when a lens is left inside the hot interior of a car,
which can reach well over 130 degrees fahrenheit, and the oil
inside a lens vaporizes.

Thanks, but this lens (28-70 mm f/4) is well known for glue separation. It looks like the fog described the a previous poster. I bet it's glue separation, but I am gonna take another look. I am deciding between taking it apart myself or selling it on eBay with clear description of the problem, "AS IS".

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Anastigmat
Forum ProPosts: 12,630
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Re: Glue separation or Fungus?
In reply to chibitul smecher, Mar 28, 2006

Zoom lenses are in general much harder to take apart than prime lenses, which have simpler construction and far fewer elements. If it is glue disintegration then there is nothing you can do about it. Oil or fungus can be cleaned but unless they are in the rear element group, major disassembly may be required.

Pentax AF mounts also have the electrical contracts which are held in place with tiny springs and pin. These can come loose and get lost as soon as the mount is removed, if not done carefully. Good luck.

chibitul smecher wrote:

Anastigmat wrote:

chibitul smecher wrote:

I have a 28-70 f/4 which apparently has some issues with the glue
between two elements coming loose causing them to separate and
there seems to be an air gap in between these elements. When I look
through the lens I see a light "haze" which covers maybe 30-40% of
the area, and it does not seem to affect the picture quality. A
potential buyer took it to a camera shop and those people said it
looks like fungus, so the buyer backed up. Now I still have the
lens and I wonder if I should try to clean it myself or sell it on
eBay AS IS with a clear explanation that there is a "haze" and I
am not sure of it's the glue or fungus.

QUESTION: how can I tell if it is glue separation of fungus????

I once bought a lens that had what the seller described as lens
separation. Upon disassembling it, I find that an internal lens
surface is actually covered by a light coat of oil from the
aperture blades. The aperture blades themselves are also soaked
with oil. The glue that holds two lens elements together usually
do not separate easily. Besides, even if the glue disintegrates,
the two lenses are held tightly together in place at the edges of
the barrel so they won't physically separate. If you have haze
inside a lens, it could be because the oil from the blades have
evaporated and redeposited on another lens surface. One way that
can occur is when a lens is left inside the hot interior of a car,
which can reach well over 130 degrees fahrenheit, and the oil
inside a lens vaporizes.

Thanks, but this lens (28-70 mm f/4) is well known for glue
separation. It looks like the fog described the a previous poster.
I bet it's glue separation, but I am gonna take another look. I am
deciding between taking it apart myself or selling it on eBay with
clear description of the problem, "AS IS".

Reply   Reply with quote   Complain
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