is THIS fungus or something else?

[Tracy Storer]

Fill with india ink and use it. I like Heliars. 105 will be great on rollfilm, 3.25" x 4.25", and will have some utility on 4"x5". (I've used a 240mm on 8"x10" for figure work indoors with slight darkening in the corners.)

[alex from holland]

When it is a non coated kens it can't be fungus.
Fungus only grows on coated lenses.

[Pfsor]

When it is a non coated kens it can't be fungus.
Fungus only grows on coated lenses.

You affirmation is not true. Non coated lenses during WWII were known as suffering from severe fungus problems in tropical countries.

[Steven Tribe]

I would like to see a reference to WWII fungus problems - some WWII lenses were coated.

The chip is very unusual. The crack and the inner shear "waves" look to be a perfect curve. The "cracks" which spread beyond the crack are due to the balsam becoming solid and shrinking in this process.

[xkaes]

I would like to see a reference to WWII fungus problems - some WWII lenses were coated.

All I can add is that the first, coated, Japanese lenses -- at least for public use -- did not appear until Minolta produced them in 1947. This is according to the George Eastman Museum.

And, NO, I am NOT saying that the Japanese had the first coated lenses! Lens development improved tremendously during the War, for military purposes, but I'm sure someone else can provide info on when lens coating started.

[Dan Fromm]

Joe, practically speaking hard coated lenses for civilian customers came in in 1946 but the exact starting date varies by manufacturer. EKCo started sometime in 1946. I have an uncoated 1946 101/4.5 Ektar, have seen coated 101/4.5 Ektars from 1946 with higher serial numbers. The oldest coated lens I've ever had was an 1944 TTH Aviar.

[Pfsor]

I would like to see a reference to WWII fungus problems - some WWII lenses were coated.

Read to your heart's delight - http://www.europa.com/~telscope/fungus.txt

[Steven Tribe]

Nice read! A couple mentions of glass etching, but the main problem seemed to optical problems with the physical presence of the fungus. Later down the text there is quite useful information about lens storage ( no wood, leather or boxes!). It is noted that various glass have quite different resistance to etching fungus.

What Alex referred to was the absence of etching fungus attack on "old" glass types. Like him, I have never seen fungus etching on "old" glass. Plenty of "dust away" fungus, though. Even lenses which have been stored in attics or garden sheds ( brass covered with deep verdigris) have OK glass!

However, I have seen some irregular blooming patterns on a few lens surfaces which could have something to do with fungus influence.
,

[Tin Can]

Very good read, tracing the battle right along.

Now some are calling mold, fungi 'Intelligent'.

https://www.quantamagazine.org/the-b...obes-20171113/

Not in one cell, but how the many act. Time-lapse microscopy photography captures their empire, not unlike cities...

[Pfsor]

Now some are calling mold, fungi 'Intelligent'.
https://www.quantamagazine.org/the-b...obes-20171113/

Interesting, indeed. Mold and fungi are highly mysterious creatures...