[mainstreetexile]

Picked up two primes at a swap meet yesterday. Realized they were probably trashed, but I got them for next to nothing, so I figured I'd buy them to try and maybe use as practice for disassembling / cleaning lenses. I've never had a lens with fungus before, so I'm hoping you folks can help id what happened here.

I bought this Pentax-M 100 f/4 Macro. The aperture isn't working (the lever on the back doesn't have any tension, just flops back and forth) and there's a lot of dust and the front elements look like this:



Is this plain old fungus? The rear elements don't look as bad, but there is some white discoloration on the fabric parts of the interior near the rear mount that look like water damage or something, but I'm guessing they're just more mold.

I also bought this Tokina RMC 300 f5.6. It works very well mechanically and it actually looks to be in pretty nice shape except for this between the two front elements:



It looks pretty dramatic, but it's not as visible when I'm not shining a flashlight from the back. Is this haze or fungus? Is there a difference? I tried it out on an APS-and it actually took some decent enough pictures for a low-end 300mm telephoto lens with this large ring on the front elements.

[manishved]

Appears to be mold/water damage....Make sure you get your flushot before opening them

[waterfall]

There is a fungus among us! White fungus to be more specific. At least it is not stachybotrus black slime mold that may yet eat Tokyo. Mold grows on cellulose and dirt. It needs moisture. Does not eat glass but does eat dead cellulose and organic stuff in dirt. I know nothing that will kill the spores inside the lens. Dryness will make the mold go dormant. But the spores wait for moisture before again erupting.

I would not attach these lenses to a new camera. They are safe only for a Kodak Instamatic, IMO. Any camera you mount these lenses on becomes open to the concentrated mold spores.

[stevebrot]

but it's not as visible when I'm not shining a flashlight from the back.

...and that is why you shine a flashlight from the back.

Wash your hands well after handling those puppies and disinfect (10% bleach) your work area as well. I would suggest ziplock bags in between your work sessions.


Steve

[Lloydy]

The Pentax 100 macro is a great lens, they fetch good money as well. So, that might not be the best lens to practice on?
It looks and sounds from your description to be in a bad way, but as long as any fungus hasn't etched into the glass - fungus secretes an acid - then the glass should clean well enough to be perfectly useable. It's hard to tell from the picture, but maybe it's just condensation and water stains? At worst, it's separation of cemented elements.
Personally I would have a go at cleaning it, but I have cleaned and repaired many lenses, and wrecked a few as well. And I doubt that it's a complicated lens.
But if you want to keep it and use it, I'd be tempted to get it looked at by someone with some experience to see if it is worth saving.
The Tokina is a cheap and cheerful 300 telephoto, it's a decent lens but there's plenty of cheap ones about. i'd practice with the Tokina.

[DeadJohn]

Others have said fungus for the Pentax-M 100 f/4. My limited fungus experience has only seen fungus that looks like threads spreading over the glass, sort of like white tree roots, never covering such a large area as seen in your 1st photo. I'm not saying they're wrong just that I've never come across fungus like that.

Is the discoloration in front of or behind the front element? If in front it might be damage from overly aggressive cleaning. If behind then fungus is more likely.

[mainstreetexile]

Well, you guys have made me nervous enough to not even want them in my apartment now, let alone near my camera I don't yet have the proper tools to disassemble and clean these lenses, and pricing them out it seems like it might not be worth the money and time, so I'll probably just get rid of them. The good news is that I bought both of the lenses together for less than the price of a pint of good beer, so I'm not out that much.

It's a little hard to tell from the picture, but it appears to me that the discoloration is on the back/inside part of the front element of the 100 and in between the front two elements of the 300. Looking a little closer, it looks like there may be some around the outside edges of part of the rear elements too (or maybe that's separation).

A bit of a tangent now, but since it's been mentioned here (maybe in jest), is lens fungus dangerous to humans?

[kiwi_jono]

I'm no expert but the 100 macro looks like element delamination to me. Seen something similar before with delmainated lenses. I believe this has a couple of grouped lenses (one near front element).

[tom1803]

The Pentax M 100mm f/4 macro is showing it's typical problem of glue deterioration of it's cemented pair elements. The affected group is easy to access but it needs to be unglued and then re-cemented with proper optical adhesive for successful repair. It's not something that an untrained person can accomplish. You will need to find a competent repair person for the job.

The Tokina on the other hand may or may not be suffering from similar fate. I'm not familiar with it's optical construction so I can't say if the affected optics is a cemented pair or not.

FYI, most lens fungus appears as fine, fibrous lines like that of a plant root. It can also start out as small round spots from which the lines can grow at later stage.

[waterfall]

Others have said fungus for the Pentax-M 100 f/4. My limited fungus experience has only seen fungus that looks like threads spreading over the glass, sort of like white tree roots, never covering such a large area as seen in your 1st photo. I'm not saying they're wrong just that I've never come across fungus like that.

Is the discoloration in front of or behind the front element? If in front it might be damage from overly aggressive cleaning. If behind then fungus is more likely.

Fungus spreads in threads called hyphae that appear like slender strings. These are the reproductive organs. Eventually the hyphae merge into a solid mass, covering Tokyo.

[stevebrot]

Eventually the hyphae merge into a solid mass, covering Tokyo.

...and as we all know, Tokyo will be destroyed! Ooops! Wrong thread!


Steve

[waterfall]

Well, you guys have made me nervous enough to not even want them in my apartment now, let alone near my camera I don't yet have the proper tools to disassemble and clean these lenses, and pricing them out it seems like it might not be worth the money and time, so I'll probably just get rid of them. The good news is that I bought both of the lenses together for less than the price of a pint of good beer, so I'm not out that much.

It's a little hard to tell from the picture, but it appears to me that the discoloration is on the back/inside part of the front element of the 100 and in between the front two elements of the 300. Looking a little closer, it looks like there may be some around the outside edges of part of the rear elements too (or maybe that's separation).

A bit of a tangent now, but since it's been mentioned here (maybe in jest), is lens fungus dangerous to humans?

I am no microbiologist but work around rotting wood buildings infested with cubical brown rot, white mold and stachybotrus. Never had any ill effects. But of course I grew up around lutefisk. May have been like a flu shot.

[DeadJohn]

Thanks to those who explained delamination. I knew what it was but not what it looked like. I've been schooled, in a good way.

[mainstreetexile]

Here are a few extra images of the 100/4, not sure if these will help clear up whether it's fungus or separation (I'm not too sure what either of those look like).



From the back, that straight line is on one of the rear elements that looks like it may possibly have separation around the edges on the side:


Discoloration of the inner fabric:

[tom1803]

One more thing regarding fungus.

There are so many stories, myths, hear-says, etc. floating about the web that it's hard to tell what the actual truth is.

From MY experience (I've been repairing lenses for a few years now, but of course my opinions could be totally wrong) the lens fungus has not had any detrimental health effects on me so I assume they are safe to humans in the small doses that one comes across in handling infected lenses. Whilst fungus spores exist everywhere, the specific type that affects lenses (more specifically, the type that likes to feast on the organic residue on the lens) may not be so common. How easily these spores gets transported from one lens to another is unknown. Once the fungus has been killed off by fungicide, UV radiation, etc. it should not grow any further (well, it's dead). To avoid growth of fungus, always store your lens in a cool, dry place with plenty of airflow. Cupboards, boxes, camera bags, or any other enclosed areas should be avoided. If you live in a humid climate, then use of a specialised dry box may be a good idea. Don't keep your lens stored away for long periods of time. Take it out regularly and use it to give it fresh air.