"Don't let a few specs of dust on your lens bother you...

[ACRosalino]

… it won't affect your images in any way".

 

I have heard that expression many times, when it comes to (old) lenses or telescopes, and I believe it basically tells the truth.

Even so, evidently I was not prepared for what I received today from evilBay:

 

 

 

Maybe in this case, I will have to open an exception and let myself be bothered?

Hopefully, this old one will not be too difficult to disassemble...

[Stefano]

Yes, a few specs of dust...

Well, probably this gray layer will give your images a foggy appearance. It may be pleasing if you want it. Some people like flares, for example.

[nfoto]

Oh dear. Does it smell as well? A lens looking this bad can have a lot of fungus inside.

 

My advice is to send it back for a full refund. Or, if you decide to keep it do clean the lens in stages by first gently blowing off as much dust as possible. Then lift off using a moisturised Q-tip or similar carefully pushing onto the surfaces. No lateral movement. In a final stage, use a microfibre cloth and ever so little window cleaning spray, still limiting movement of the cleaning gear as much as possible.

 

And yes, of course give the seller full negative feedback on eBay. He certainly did his utmost to deserve a proper rating.

[ulf]

Lens fungus can sometimes etch the lens's glass surfaces.

That is a condition that cannot be restored by cleaning.

Even if you are able to clean away all the fungus, some traces of it will remain in the surface structure.

[nfoto]

That is correct. Fungus really is able to "eat" through coatings.

[enricosavazzi]

In some cases I got lenses where molds had eaten away the lens coatings but spared the glass underneath. This might actually slightly improve the UV transmission of some lenses.

 

This is not the worse I have seen in eBay merchandise. Several years ago I got a Wild stereomicroscope "in good condition" off eBay. It looked passable externally, but the metal internals were rusted and corroded, and the optics smashed into small pieces. Someone must have dunked it overboard into the sea, then taken it out and wiped it dry externally without a thought to saltwater and loose glass bits left inside.

[eye4invisible]

Looks like sawdust to me. If that's all external only, a wipe down with a soft cloth might be all it takes.

[ACRosalino]

Well, it turns out that it looked far worse than it really was!

 

I have no clue where all that dust, pollen, sawdust or whatever it was came from. Seller advertised a clean lens and he said it was clean when he shipped it... go figure. Maybe something happened during transport... which he could have prevented, anyway, if he had placed the lens inside a plastic bag - on the other hand, dust was outside the leather case and also inside, lots of it!

 

So I got rid of the leather case (maybe it was desintegrating itself?) and cleaned the outside of the lens the best I could.

Of course, with so much dust allover and lenses from those days not being exactly dust proof, some of it found its way to the inside/optical surfaces.

 

Fortunately, this one was quite easy to open: just by twisting the upper barrel, one can access the single front element and the massive doublet lens in the middle.

I cleaned those, left the iris blades alone and the rear optical element - I think it looks reasonably good, especially for its age:

 

 

We shall see how it performs, once I receive the required Petri-Sony E mount adapters!

 

PS: no negative feedback for the seller, he apologized and offered a 50% refund... lens really was "dirt cheap" :-)

[nfoto]

"Dirt cheap" indeed.

 

In fact used the Petri 135 on my Z6 today for IR. No hot spots and results looked pretty good.

[Andrea B.]

AC, that photo made me laugh!

 

It probably was the case deterioration. I had that happen with a UAT lens. The glue under the case lining had dried out, the lining came loose and the lens arrived covered in glue "dust" which had leaked all over everything. The lens and its filters all got cleaned up. I've never quite figured out how to restore the case. I will probably not bother even though it has some minor historical interest.

[bvf]

Is this what was meant by "grain" in the days of film?