Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-10-2012, 02:37 AM   #16
Forum Member




Join Date: Feb 2012
Location: Vancouver
Posts: 96
Original Poster
OK, all this talked scared me enough. Now the sick lens is inside a zip lock bag, then inside two plastic bags sitting in a drawer in the kitchen. I will wait until the weather is nice and do the work outside. Otherwise it is inevitable that I will sneeze or something and get lens fungus spores all over everything.

I suppose being a germophobe in the first place doesn't help, either - but at least I know how to do things without touching anything.

03-10-2012, 02:50 AM   #17
Pentaxian
kh1234567890's Avatar

Join Date: Sep 2010
Location: Manchester, UK
Photos: Gallery
Posts: 2,327
QuoteOriginally posted by atekant Quote
OK, all this talked scared me enough. Now the sick lens is inside a zip lock bag, then inside two plastic bags sitting in a drawer in the kitchen. I will wait until the weather is nice and do the work outside. Otherwise it is inevitable that I will sneeze or something and get lens fungus spores all over everything.
You are mad. It is not the same stuff that grows on your old cheese. It will not suddenly cover all of your lenses and then your house windows and then any glass within a mile radius. It only ended up growing on that lens because someone'd kept it in a damp camera bag in their loft for years and years.
03-10-2012, 03:38 AM   #18
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,535
QuoteOriginally posted by atekant Quote
I suppose being a germophobe in the first place doesn't help, either - but at least I know how to do things without touching anything.
LOL then perhaps I shouldn't have used that petri dish analogy, besides penicillin is a great fungus without its discovery I doubt medicine would have gotten to where it is today.

But onto the subject at hand: I would suggest you get some rubbing alcohol, it useful for cleaning fungus out of lenses because of its antiseptic properties and it is also very good at cleaning off oils which are what probably caused the fungi to adhere to the surface of the lens in the first place**, the fluid can leave a residue but it is easily cleaned off with a micro-fibre cloth.


* Zippo lighter fluid can also be used in a pinch, but it will leave a residue behind.

** it is also extremely useful for cleaning aperture blades that have become sticky due to oil getting on them.

Last edited by Digitalis; 03-10-2012 at 03:47 AM.
03-10-2012, 03:41 AM   #19
Veteran Member




Join Date: Mar 2010
Location: NewYork
Posts: 899
Something to be aware of. Lens fungus can not eat glass or the coatings on the glass. What it can eat are some of the organic glues that are used to bond elements together, and some lubricants. In the case of it eating the glue causing separation or hazing, it has to start from the edge where it can get at the glue between the layers of glass. With the edges pressed against the metal they mount to, I'm guessing there is not a lot of air flow. The fungus was probably there from the factory (lenses are not built in clean rooms that are fungus free and like everywhere else, lens factories have fungus). As far as fungus on the glass, there has to be lubricant deposits on the glass for the fungus to eat, and humidity has to be above 70% long enough for the fungus to start to grow. If there is a suitable lubricant on the glass for the fungus to eat, then the fungus produce acid as a byproduct, and that is what damages the coatings and the glass.

If I am not mistaken (I'm not certain on this one), fungus needs carbon to eat so the lens glue and or lubricant has to be organic in nature). I'm guessing that includes hydrocarbons but not plastic based synthetic lubricants? I do know that some lubricants are not so prone to be good food for fungus.


Last edited by ripit; 03-10-2012 at 03:48 AM.
03-10-2012, 03:51 AM   #20
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,535
QuoteOriginally posted by ripit Quote
Something to be aware of. Lens fungus can not eat glass or the coatings on the glass.
Incorrect, there are certain species of fungi that can produce compounds that physically etch the surface of the lens, completely destroying it in the process*. There are some fungi that can eat the organic compounds in the cement between the lenses however this only happens with older lenses. This is an unheard of rarity for this to happen with modern optical grade polycarbonate cements as the polymers that make up the modern cement are extremely difficult to break down.

*Curiously radioactive thorium glass or lens elements with high levels of lanthanum do not seem to suffer from fungus issues from my experience, and ED glass although physically softer than borosilicate glass typically used in lenses also seems to be resistant to this kind of attack.

Last edited by Digitalis; 03-10-2012 at 03:59 AM.
03-10-2012, 04:17 AM   #21
Forum Member
Twarp's Avatar

Join Date: Jan 2012
Photos: Gallery | Albums
Posts: 79
QuoteOriginally posted by kh1234567890 Quote
You are mad. It is not the same stuff that grows on your old cheese. It will not suddenly cover all of your lenses and then your house windows and then any glass within a mile radius. It only ended up growing on that lens because someone'd kept it in a damp camera bag in their loft for years and years.
AKA sealed in a plastic bag in a kitchen drawer
Don't forget the sandbags with silica gel...
03-10-2012, 05:21 AM   #22
Veteran Member




Join Date: Mar 2010
Location: NewYork
Posts: 899
QuoteOriginally posted by Digitalis Quote
Incorrect, there are certain species of fungi that can produce compounds that physically etch the surface of the lens, completely destroying it in the process*. There are some fungi that can eat the organic compounds in the cement between the lenses however this only happens with older lenses. This is an unheard of rarity for this to happen with modern optical grade polycarbonate cements as the polymers that make up the modern cement are extremely difficult to break down.

*Curiously radioactive thorium glass or lens elements with high levels of lanthanum do not seem to suffer from fungus issues from my experience, and ED glass although physically softer than borosilicate glass typically used in lenses also seems to be resistant to this kind of attack.
By eat the glass and coatings, I mean they can not consume them. Unless I am misinformed, fungus can not grow on a perfectly clean glass element, be it a coated one or not. They can however consume other contaminants with the most common in a lens being lubricant that has gassed out or otherwise deposited itself on the glass. Some fungus can produce acid which as you said, can destroy the coating and etch the glass causing permanent damage. They don't actually eat or consume the glass or coating though, so there must be another food source on the surface of the lens for it to grow and damage the lens with acid. I wonder if some lenses are more prone to fungus because of the nature of the lubricants used?
03-10-2012, 06:41 AM   #23
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,535
QuoteOriginally posted by ripit Quote
eat the glass and coatings, I mean they can not consume them
no, that would require some pretty exotic mutations for fungi or bacteria to do that*. In my experience the biggest problem is dust motes getting on the lenses themselves that provide food for fungi - not the coatings or the glass for that matter. Lubricants certainly can be a problem: stray lubricant on a lenses surface provides an excellent environment that the fungi can adhere to and start multiplying. Though a speck of dust here and there isn't likely to be a problem, however I have heard of people buying brand new 400mm f/2.8 lenses and completely flipping out after a year or so over the audacity of a single speck of dust defiling their precious lens - people like that really tick me off.


*though as an interesting anecdote: Nylon can be consumed by bacteria, this was discovered around 1975 in Japan where a group of scientists discovered a strain of bacteria living in water contaminated by wastewater from a nearby nylon factory. These bacteria evolved to produce an enzyme dubbed Nylonase - which is capable of eating many of the by-products of nylon production.

Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
fungus, k-mount, lens, lens fungus, pentax lens, slr lens, time
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help with lens fungus. adamc Troubleshooting and Beginner Help 12 10-04-2011 02:20 PM
is this lens fungus? apakoh Troubleshooting and Beginner Help 13 07-31-2011 09:48 AM
fungus lens ahniao78 Troubleshooting and Beginner Help 2 01-22-2011 08:35 AM
Cleaning fungus out of a lens. John nich Pentax SLR Lens Discussion 9 07-28-2010 05:48 PM
Is this lens fungus? PacificCanuck Pentax SLR Lens Discussion 6 07-13-2010 08:41 AM



All times are GMT -7. The time now is 08:26 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top