Removing fungus from Pentax F 70-210mm front glass?

radomir · 08-11-2010, 07:37 AM

Hi,
I might be able to get a Pentax F 70-210 for a low price (sold "as is"), but it has fungus inside the front glass. I was wondering if anyone has successfully tried to disassemble this type of lens to clean the front glass?

Any help would be much appreciated.

Thanks
Radomir

Adam · 08-11-2010, 09:43 AM

Disassembling a zoom lens is extremely hard, so I'd suggest against getting the lens in the first place.

radomir · 08-11-2010, 03:05 PM

Thanks very much Adam

hangu · 08-11-2010, 03:55 PM

Originally posted by Adam

Disassembling a zoom lens is extremely hard, so I'd suggest against getting the lens in the first place.

I'd agree if the fungus were in the middle elements. It should be relatively easy to obtain access to the front element. All you would need would be a rubber stopper to twist out the face plate and possibly a spanner wrench to unscrew the front element.

I could be wrong about the F series zooms. I've never seen one but it should be relatively similar.

nanhi · 08-12-2010, 12:48 PM - **1 Like**

I agree with Mr. Hangu. Please don't be afraid to open up the front element. It is very easy. If the front element is held down by a ring screw then use a divider or a lens wrench (or an internal spring clip wrench). This ring will have 2 slots. Carefully insert the wrench pins in the slots and turn the ring counter clockwise.
If it has a name plate hold down ring as Hangu said, you will need a) plastic pipe T-joint from Home Depot. Ensure the diameter is right for your lens. b) cut a rubber washer from a 2mm or thicker rubber sheet to go round the lens and sit snug on the lens name plate ring. Then press down firmly on the rubber washer with the T - pipe joint and twist it counter clockwise. Friction force does the trick. Note: rubber camera tools for this job are available but the set will cost a lot.
The rear element is the easiest to open. Ofcourse as Adam suggested I wouldn't try dismantling the inner lenses - zoom optics are too complicated,

radomir · 08-13-2010, 04:11 AM

Thanks everyone, it looks like it might be an interesting challenge. If I end up owning the lens, I'll give it a try (and post the results if successful).

08-11-2010, 07:37 AM	#1
radomir New Member Join Date: Aug 2010 Location: Brisbane, Australia Posts: 6	Removing fungus from Pentax F 70-210mm front glass? Hi, I might be able to get a Pentax F 70-210 for a low price (sold "as is"), but it has fungus inside the front glass. I was wondering if anyone has successfully tried to disassemble this type of lens to clean the front glass? Any help would be much appreciated. Thanks Radomir

08-11-2010, 09:43 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,594	Disassembling a zoom lens is extremely hard, so I'd suggest against getting the lens in the first place. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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08-11-2010, 03:05 PM	#3
radomir New Member Join Date: Aug 2010 Location: Brisbane, Australia Posts: 6 Original Poster	Thanks very much Adam

08-11-2010, 03:55 PM	#4
hangu Veteran Member Join Date: Feb 2010 Location: NYC Photos: Gallery Posts: 1,071	Originally posted by Adam Disassembling a zoom lens is extremely hard, so I'd suggest against getting the lens in the first place. I'd agree if the fungus were in the middle elements. It should be relatively easy to obtain access to the front element. All you would need would be a rubber stopper to twist out the face plate and possibly a spanner wrench to unscrew the front element. I could be wrong about the F series zooms. I've never seen one but it should be relatively similar.

08-12-2010, 12:48 PM - 1 Like	#5
nanhi Veteran Member Join Date: May 2009 Location: Bangalore, India Photos: Gallery \| Albums Posts: 469	I agree with Mr. Hangu. Please don't be afraid to open up the front element. It is very easy. If the front element is held down by a ring screw then use a divider or a lens wrench (or an internal spring clip wrench). This ring will have 2 slots. Carefully insert the wrench pins in the slots and turn the ring counter clockwise. If it has a name plate hold down ring as Hangu said, you will need a) plastic pipe T-joint from Home Depot. Ensure the diameter is right for your lens. b) cut a rubber washer from a 2mm or thicker rubber sheet to go round the lens and sit snug on the lens name plate ring. Then press down firmly on the rubber washer with the T - pipe joint and twist it counter clockwise. Friction force does the trick. Note: rubber camera tools for this job are available but the set will cost a lot. The rear element is the easiest to open. Ofcourse as Adam suggested I wouldn't try dismantling the inner lenses - zoom optics are too complicated,

08-13-2010, 04:11 AM	#6
radomir New Member Join Date: Aug 2010 Location: Brisbane, Australia Posts: 6 Original Poster	Thanks everyone, it looks like it might be an interesting challenge. If I end up owning the lens, I'll give it a try (and post the results if successful).

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