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Photo Forum / Film Photography / Medium format / November 2007Lens problem - fungus??
Chaps, noticed something odd on the 135mm lens for my C330f. What appears to be a pale whitish smear of dirt - however not on the outside or film side surfaces of the lens, somewhere within the lens. Is this the dreaded mould or cement deteriorating? Put the lens outside in the sun until it rained. Now packed it in a platic bag with dessicant. Anything else I can do? Is it catching? Pete  Signaturehttp://www.petezilla.co.uk > Chaps, > [quoted text clipped - 7 lines] > > Pete Hi, Pete, Can you see if the deposit is between 2 lenses in a group or is on a glass-air interface? If the first it is probably separation/cement failure. If the second is can be fungus or another deposit. Fungus can be abated with the lens-in-the-sun trick, but that doesn't always take care of the problem. If it is separation you should probably consider replacing the entire lens -- C330 lenses aren't that expensive. If it is some kind of deposit a good camera repair shop should be able to clean it. Hope this helps, k Signaturejai bhagavan > Can you see if the deposit is between 2 lenses in a group or is on a > glass-air interface? If the first it is probably separation/cement > failure. If the second is can be fungus or another deposit. Fungus can > be abated with the lens-in-the-sun trick, but that doesn't always take > care of the problem. Hard to say exactly where it is. Just blasted the lens with a UV lamp, though as the UV lamp is probally intended for parties etc I'm not sure it is short enough wavelength to do the trick. Can't do any harm though. > If it is separation you should probably consider replacing the entire > lens -- C330 lenses aren't that expensive. If it is some kind of deposit > a good camera repair shop should be able to clean it. Suspect it is the latter - I've heard the fungus described as 'snowflakes' etc, and it is nothing like that. I suppose the best bet is to just keep using it unless I become unhappy with the images it produces. If it does go too far I could try swapping the viewing and taking lenses, nothing to loose at this point. Like you say, probally not worth spending money on, especially as it looks like one of the previous owners used a gritty rag to clean it. > Hope this helps, Cheers. Pete Signaturehttp://www.petezilla.co.uk On 12 Nov, 09:32, Peter Chant <REMpete...@CAPpetezilla.ITALSco.uk> wrote: > > Can you see if the deposit is between 2 lenses in a group or is on a > > glass-air interface? If the first it is probably separation/cement [quoted text clipped - 25 lines] > > --http://www.petezilla.co.uk Fungus starts out innocent-looking, from what I have seen of old cameras, as a smear of grease. Later the grease forms into blobs and the blobs sprout filaments and then you know you have fungus. If caught at the "smear of grease" stage then it might clean off without any problems, though, if on a coated lens, it might have adversely affecting the coating somewhat. > Fungus starts out innocent-looking, from what I have seen of old > cameras, as a smear of grease. Later the grease forms into blobs and > the blobs sprout filaments and then you know you have fungus. If > caught at the "smear of grease" stage then it might clean off without > any problems, though, if on a coated lens, it might have adversely > affecting the coating somewhat. It was muck on the front of the rear element. Well, probaly foolishly, I tentatively unscrewed the front of the lens, on the basis of if it looked complicated I'd put it right back. All the glass elements came out and it was a simple job to remove the assembly holding the rear element. Looking at the viewing lens there is similar muck on the front of the rear element. This one is a lot stiffer, I need to get a bit more purchase to take it apart. Bit worried how muck, 'smear of grease' gets inside the lens like this. Pete Signaturehttp://www.petezilla.co.uk > > Fungus starts out innocent-looking, from what I have seen of old > > cameras, as a smear of grease. Later the grease forms into blobs and [quoted text clipped - 19 lines] > > --http://www.petezilla.co.uk If the lens was ever in warm humid conditions and then later cooler the condensation would come out of the air and settle on the lens surfaces inside. I guess it would more readily condense on fungus spores. > If the lens was ever in warm humid conditions and then later cooler > the condensation would come out of the air and settle on the lens > surfaces inside. I guess it would more readily condense on fungus > spores. Reasonably well sealed, so I can't see you getting much in the way of condensation. Packed in plastic bag with dessicant just in case. Ought to shoot a test film before much longer. Cleaned surfaces with vinegar, as suggested on a website somewhere, as it kills fungus (use at own risk!), and reassembled. For the viewing lens the front of the rear element looked reasonably clean until I breathed on it, it was obviously splodgy and dirty. What looked like a couple of scratches and a few other marks would not clean off. Would have taken a photo but have not got DSLR and no film in film SLR's at the moment. Hopefully that's the end of it. Pete Signaturehttp://www.petezilla.co.uk > > If the lens was ever in warm humid conditions and then later cooler > > the condensation would come out of the air and settle on the lens [quoted text clipped - 7 lines] > Cleaned surfaces with vinegar, as suggested on a website somewhere, as it > kills fungus (use at own risk!), and reassembled. I would imagine that vinegar kills lens coatings as the coating is alkaline (as is the glass in lenses). > For the viewing lens the front of the rear element looked reasonably clean > until I breathed on it, it was obviously splodgy and dirty. What looked [quoted text clipped - 8 lines] > -- > http://www.petezilla.co.uk > I would imagine that vinegar kills lens coatings as the coating is > alkaline (as is the glass in lenses). Pity I did not remember the web page - the guy who wrote the page gave the impression he knew what he was on about. No, did not appear to damage coating. However YMMV. By the magic of Google: http://www.mypentax.com/Fungus.html compared to hydrogen peroxide and ammoina and _soft_ metal polish vinegar is likely quite mild. Pete Signaturehttp://www.petezilla.co.uk > > I would imagine that vinegar kills lens coatings as the coating is > > alkaline (as is the glass in lenses). [quoted text clipped - 6 lines] > hydrogen peroxide and ammoina and _soft_ metal polish vinegar is likely > quite mild. What you are seeing sometimes is advice about fungus that applies to old cameras with lenses that were made before coatings were introduced. > What you are seeing sometimes is advice about fungus that applies to > old cameras with lenses that were made before coatings were introduced. Well, a bit late now, but it appears not to have done any harm. Interesting to note, in eighteen years of wearing glasses with coated lenses I've only once had a problem with something attacking the coatings on one pair, and that was a long time back - something quite nasty. Pete Signaturehttp://www.petezilla.co.uk RolandRB wrote: > I would imagine that vinegar kills lens coatings as the coating is > alkaline (as is the glass in lenses). 5% acetic acid can damage glass? I keep my glacial acetic acid (99%) in a glass bottle with no harm (for mixing stop bath). Hydrochloric and Nitric acids do not harm glass (both used in etching and lithography). Hydrofluoric acid does damage glass. I have no idea what damages lens coatings besides abrasion. --krishna Signaturejai bhagavan > RolandRB wrote: > [quoted text clipped - 7 lines] > Hydrochloric and Nitric acids do not harm glass (both used in etching > and lithography). There a difference between glass, as used in glass bottles, and glass, as used in making lenses. Usually, a high refractive index is sought after in glass for making lenses and this can be achieved by mixing in metal oxides of various sorts. Metal oxides are alkaline and can be attacked by acids. For example, I am sure you are aware how lead crystal cut glasses refract the light in a spectacular way. In this case lead oxide has been mixed with the silicon oxide that is pure glass to increase the refractive index to give this effect. > Hydrofluoric acid does damage glass. > > I have no idea what damages lens coatings besides abrasion. Some lens coatings are metals. Such coatings can be damaged by acid unless these coatings in turn have been given protective coatings to prevent this happening through normal use. > --krishna > > -- > jai bhagavan > Some lens coatings are metals. Such coatings can be damaged by acid > unless these coatings in turn have been given protective coatings to > prevent this happening through normal use. It would appead from here that caustic cleaning agents are more of a problem, however, there is reference to problems with an acid version of windex. Not familiar with that product, as we don't have it over here. http://www.microscopy-uk.org.uk/mag/artfeb04/cdclean.html Pete Signaturehttp://www.petezilla.co.uk > It would appead from here that caustic cleaning agents are more of a > problem, however, there is reference to problems with an acid version of > windex. Not familiar with that product, as we don't have it over here. This site discusses use of ammonia, vinegar and naptha. http://www.prairienet.org/b-wallen/BN_Photo/GenTechLenses.htm Signaturehttp://www.petezilla.co.uk On 19 Nov, 19:54, Peter Chant <REMpete...@CAPpetezilla.ITALSco.uk> wrote: > > It would appead from here that caustic cleaning agents are more of a > > problem, however, there is reference to problems with an acid version of [quoted text clipped - 5 lines] > > --http://www.petezilla.co.uk It doesn't "discuss" it. It mentions the use of ammonia and vinegar. It would be wise to read it in context as it might apply to pre-coated lenses. > It doesn't "discuss" it. It mentions the use of ammonia and vinegar. > It would be wise to read it in context as it might apply to pre-coated > lenses. OK, poor choice of words. Not trying to start an argument by the way, just doing a bit of research. However, this is usenet and it is easy to give the wrong impression. Thanks for your comments. I think before approaching diy of this sort you need to weigh up the options - how much is it worth to fix by a professional, how much to simply replace and how much will you be annoyed if it goes wrong. I suspect the price of a repair would go a long way towards a replacement, and a replacement would likely not have the fine scratches from cleaning like this one. Pete Signaturehttp://www.petezilla.co.uk >Hydrofluoric acid does damage glass. And bones - never get it on your skin. SignaturePaul Friday > And bones - never get it on your skin. Isn't that the stuff that goes through your flesh and destroys the bone underneath. Nice stuff. Interestingly apparently some of the damage wrecked by fungus is the fungus excreting hydrofluoric acid. How does it do it without killing itself? To lower the tone, you think you've had it bad after a curry... I spotted in an old photography book instructions on etching a photo onto glass. It involved coating the glass with a albumen and a sensitising agent and at some point using bitumen powder, to act as a mask, the bitumen adhering to the emulsion created with the albumen and sensitising agent. All fine up to now (ok powerdered bitumen anyone). I decided not to bother when it required the glass plate to be held over fuming hydroflouric acid. Signaturehttp://www.petezilla.co.uk > In message <mahamantra-F8BBD2.22293115112...@reader1.panix.com>, > krishnananda <mahaman...@yahoo.in> writes [quoted text clipped - 4 lines] > -- > Paul Friday It might be oxalic acid that the fungus is using. This is an organic acid known to attack e-glass which is the glass used in glass fibre. E- glass contains metal oxides to give it low electrical conductivity properties (it also gives it increased strength) and optical glass contains similar metal oxides, some of them the same. It will be a very slow reaction, though. Not like watching hydrofluoric acid etch glass. In message <93f994c8-cb02-428e-a2bc-70712262bd4e@w34g2000hsg.googlegroups.com>, RolandRB <rolandberry@hotmail.com> writes >It might be oxalic acid that the fungus is using. Then keep your lenses away from rhubarb leaves. On the other hand, a strong tea made from said leaves is good for removing rust stains. Just don't drink the stuff. SignaturePaul Friday > In message > <93f994c8-cb02-428e-a2bc-70712262b...@w34g2000hsg.googlegroups.com>, [quoted text clipped - 7 lines] > -- > Paul Friday Sage words from Paul. For those of you who store your lenses away wrapped in rhubard leaves, think again! >> In message >> <93f994c8-cb02-428e-a2bc-70712262b...@w34g2000hsg.googlegroups.com>, [quoted text clipped - 10 lines] > Sage words from Paul. For those of you who store your lenses away > wrapped in rhubard leaves, think again! Thyme to take heed. Signaturehttp://www.petezilla.co.uk |
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