Separation or fungus?

[IanG]

In my youth I studied micro-biology at University and the pattern of the growth would depend on the exact fungi species and the conditions at the time it occurred. The pattern on Rogers lens is a typical growth pattern.

Ian

[Steven Tribe]

Whatever it is - there will be no damage to the glass! The real problem is growth on coated lenses which releases HF acid, and which is a great etching compound on glass.

[hoffner]

In my youth I studied micro-biology at University and the pattern of the growth would depend on the exact fungi species and the conditions at the time it occurred. The pattern on Rogers lens is a typical growth pattern.

Ian

The fact that the pattern is similar to a growth pattern is no indication in itself of its biological origin. In that Steven is right - crystallising matters also evolve in a similar way.

[Francisco J. Fernández]

The fact that the pattern is similar to a growth pattern is no indication in itself of its biological origin. In that Steven is right - crystallising matters also evolve in a similar way.

It is a pattern of growth, according.

a living organism and a crystal system can follow a similar pattern.

Have you looked at with a magnifying glass?

then clearly is not a crystalline body. no it is not.

[IanG]

It is a pattern of growth, according.

a living organism and a crystal system can follow a similar pattern.

Have you looked at with a magnifying glass?

then clearly is not a crystalline body. no it is not.

Totally agree.

The fact that the pattern is similar to a growth pattern is no indication in itself of its biological origin. In that Steven is right - crystallising matters also evolve in a similar way.

In this caseit's clearly not the more typical filament type growth that looks more like the Crystalline issues Steven Tribe alludes to. One of my friends buys and sells a lot of lenses (mostly modern), he lives on a Peninsula (Cornwall) and finds a much high percentage (than you'd expect) of lenses have fungus. He puts it down to the sea air and a high humidity throughout the year.

However I think Roger's lens has actually been stored in far worse conditions (for a while) because this isn't the usual type of fungal attack. It's very definitely organic and I've seen a similar fungal attacks (same shape) on negatives and prints stored in conditions where you occasionally get extreme damp. First was my Grandmothers cellar where she stored he photos - normally very dry but she didn't know there was a stream under a flagstone that occasionally made it extremely damp. The other was a museum I worked for who had their photo archive in their basement but the River would flood it.

When we look at fungal attacks on lenses think laterally, we get athletes foot, we eat mushrooms, blue cheeses. all very different and that's the same with with regards to fungi etc, attacks lens.

Then we are forgetting that in the right conditions balsa can also be attacked by bacteria.

Ian

[Roger Hesketh]

Thank you Steven for your kind words and your assessment. Leigh thanks for the link.I was aware of Ginette's post. This is quite different.Thank you all for your imput. I now feel less like I have asked a stupid question that had an obvious answer as we have clearly had divided opinion amongst people who's opinions I respect and value

In my youth I studied micro-biology at University

So did I. Something else we have in common. After I decided teaching was not for me I worked for a few years as a Biology Technician at our local Grammar School preparing apparatus and materials for practical lessons. Actually being a Technician can be fun as you have a wide range of playthings and resources at your disposal and are encouraged to play with them. We did quite a lot of microbiology. I have poured and prepared thousands of Agar plates and assisted in the interpretation of results of microbiological practical work. The point I am trying to make is I am familiar with many of the fungal growth forms and in this case with this lens I am not sure. The fine detail that is missing from the photographs is that within each dendritic lobe their appears to series of conchoidal concentric fractures. This does look to me like mechanical damage to the balsam.

I strongly suspect you are ALL at least partially correct in your assessments and also that the condition of this lens has been caused by poor storage as Ian suggests. On close inspection their is just a hint of a wisp of hyphae between the two front elements. Of similar type to that which Leigh and Fransisco describe. That in the rear group is very different and I suspect may be caused by a process similar if not identical to the process Steven describes perhaps initiated by fungal action as I have now found a wisp of what looks like it elsewhere in the lens. So clearly it has been stored at some time in conditions that encouraged fungal growth. I have learned something. I was not aware that fungal growth could occur between cemented surfaces.

Jim I am not familiar with the term film pack camera and do not know what you mean. Ian the lens is the same as yours.Just in a different mount. It is a focusing mount not a sunken mount as fitted to press reflex camera. The brass lugs attach to the the focusing ring not to the aperture ring as they would on a sunken mount lens.

It is a recent purchase as I am sure you have suspected. It was an impulse purchase and one I am not sure I know what to do with. I have possibly better 6" Tessar type lenses. I have a 152mm Ektar and a coated 6" Ross Xpres for instance. Possibly it could be used as a portrait lens on roll film. Shallower depth of field than the other lenses mentioned. Lower in contrast, not as sharp as a slower Tessar I am guessing, softer wide open possibly. I do not know. If you have and use such a lens I would like to hear your experiences with it. I paid the princely sum of £2 for it at a car boot sale last week. At that price even though I have more than enough lenses I could not resist it.