[Gerry Maguire]

I have aquired a Takumar 28-80mm f3.5-4.5 A lens.as there is some fungus in the lens .I would be obliged if someone could tell me how to disassemble the lens. I have just moved from Nikon to Pentax and am not familiar with pentax lenses. GERRY

[noblepa]

Lens fungus is extremely difficult to remove. If you miss even a couple of spores, it will just return.

Fungus also has a tendency to etch the coatings. In extreme cases, it can even etch the glass itself. Neither can be repaired.

I agree with dcshooter that the lens may not be worth the effort. Personally, I wouldn't risk having an infected lens in my collection.

[Gerry Maguire]

Pretty much everything noblepa said about fungus is 100% untrue. Fungus spores are ubiquitous in the environment, including all over every single element of every lens that you own already. Furthermore, lenses, particularly vintage ones, are almost never made in clean room conditions and breathe air in and out during use, so they are constantly pumping spores in and out, whenever and wherever you use them. One lens can't "infect" another one, since all lenses are "infected" already, full stop. The only variable determining whether fungus will grow is whether it is exposed to conditions favorable to fungus growth. The myth of lenses infecting each other is just that. A myth.

Whether fungus grows or not depends entirely on the conditions the lens is stored in. If you keep it in a cool dry place with light, a lens, even if it is riddled with fungus already, it will not grow any more. If you take a perfectly "clean" lens and leave it in dark and damp conditions, it will grow fungus, since the spores are already there.

Pentax coatings also tend to be among the most fungal resistant and only etch with high level infections. Contrast this with, for example, Tamron BBAR coatings, which etch very easily. The vast majority of the time, they can be cleaned with no lingering ill effects.

The reason I questioned whether this lens is worth cleaning or not hinges solely on the risk/reward tradeoff and amount of effort and frustration potentially involved. If you've never cleaned a lens before, there is a good chance you will ruin this one (at least beyond your own ability to repair) by taking it apart. If you don't have the tools, they will cost more than a replacement lens. And if the fungus isn't having any effect on your images, there isn't really a good reason to remove it beyond your own satisfaction, since it's not a valuable enough lens that cleaning it will enhance resale value in any way.

On the other hand, I have done tons of lens cleanings, and I'm always happy to lend advice to those who are interested in learning the ins and outs of lens repair, so if you're simply looking at this lens as a way to learn, then by all means, feel free to ask for any advice you might need, including by PM.

Just really wanted to know how to disassemble the lens .If anyone had a diagram of the lens I would be grateful for a copy . Thanks

[Gerry Maguire]

Have managed to disassemble the 28-80mm takumar A lens as such,but could someone tell me if rear element can be taken apart as this is were the fungus is. Thank you. Gerry