fungus... how to tell?

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hi there folks---

well, am having a blast taking pictures. it's been a few months now that i have gotten into this hobby and have now a collection of hexanon lenses.

but, now i start reading about fungus and thinking i was so stupid for not being aware of this when i bought these lenses. they all seem to take great pics (28/1.8, 40/1.8, 50/1.7, 135/3.2, 70-200 vivitar.

so, the question is: how does one judge the status of the lens? i have read posts here about how to determine age (AE vs. EE, etc.)... but, how does one see fungus? do you look directly at the lens? do you look through the camera? and how does one know if the coating is messed up?

thanks so much, paul.

http://polymer.bu.edu/paul/

-- Anonymous, February 09, 2000

Answers

Lens inspection for fungus

Paul,

My experience has been that fungus can usually be seen as a spiderweb on the inner lens surfaces. Set the lens to the manual setting for its largest aperture. Then look into, not through, it. If your eyes are old and weak like mine, reading glasses or a magnifying glass help. I have a Hexanon 50mm f1.7 here as a sample, and, with a magnifier, it's very easy to see it.

As for inspecting the lens coating for deterioration, again use the magnifying glass. Hold the lens at an angle, looking across its surface. Move the lens until the color of the coating becomes apparent. This should appear as a smooth coating. Any crazing, or peeling are a definite no-go. I have seen coating failure that has the texture seen when you put oil based paint over latex, giving that "crackly" look.

Caveat emptor!

-jwk-

-- Anonymous, February 09, 2000


Looking for Fungus; Coatings Too

Paul, I agree with James as to how to look for the fungus and would add my own experience with it. Besides the spidery look, molds and fungus also can come in a round form. It will look like a small black dot with a slight haze halo around it. Fungus is almost always inside the lens, rarely on the rear element, very rarely on the front element. And it grows, and grows, and grows. It can be professionally cleaned if you can afford it or the lens is worth it to you. Now, the coating is usually quite obvious when it is damaged, especially on modern lenses because it is much harder than in older designs. In the past, you could literally wipe the coating off if you were a bit too brisk when cleaning the lens. Lenses made in the last 30 years or so are much safer in this regard. However, coating damage can disguise itself at times. It can look like a smear that goes away when freshly cleaned, but re-appears later. This type can be especially hard to detect when in a buying situation where you don't have the time or wherewithal to check it out. Also, as James said, damage can look like an orange peel and if someone tells you it just needs a good cleaning, DON'T believe them. Similarly, don't accept a lens that looks even the least bit hazy, front, inside, or back.

Jon from Deepinaharta, Georgia

-- Anonymous, February 09, 2000


thank you for your insightful advice. i feel a bit guilty always being the one asking questions. but i promise i will make up for it as i learn more.

so, i looked at all the lenses with the naked eye and with a handheld 3.5X magnifier... now i am totally confused and disheartened.

i see black speckles of various sizes (all are very tiny) in all the lenses that do not go away when i clean them. they seem to be right behind the front element, but this may be some optical illusion for me.

some have more, some less. the 50mm which has been sitting in an attic for years has a lot of specs. the 135mm which i just bought new in the box has only a couple of very tiny specs. but nothing looks like spider webs.. question: would the spider webs you talk about be largish? or are we talking tiny?

the camera, by the way has similar specs of "dust" on the prism (you can see it when you look through the finder).

so, my questions are: 1. is what i am seeing fungus or dust? 2. if it is fungus, does this effect the picture? 3. if it is dust, does it effect the picture? 4. in either case, should i have the lenses cleaned?

but, overall i am disheartened. i was so excited when i learned about the konica's and their great quality. i have a strong desire to learn to take really good pictures, and now i am concerned that these lenses are all crap.

thanks again everyone, paul.

-- Anonymous, February 10, 2000


fungus and lens dust...

thanks, everyone, for your helpful comments.

i also found some great discussions on the photo.net site. go to photo.net/photo, click on "original Q&A" and then "search". if you search on "fungus" this will give you some great links. Also "lens dust" will give you some different hits.

the good news: apparently lens dust (specs) is very common, but doesn't affect pictures considerably (if at all).

thanks again, paul.

-- Anonymous, February 10, 2000


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