Grey Spots on Lens Element?

[Tom Taylor]

Yesterday afternoon I noticed 3 circular grey spots on the rear element of a 105mm SMC Pentax 67 lens as if 3 liquid drops fell there. With a little condensation from my breath and a lens cloth they readily wiped away clean. But I have never seen anything like that on any of my lens. Does anyone have an idea of what it could be? The lens is kept stored in an aluminum case with the camera and other lens in its soft case with both caps and a UV filter on the front element. I last used the lens about 2 months ago and the rear element was clean.

Thomas

 

[AgX]

At extreme situation condensation may occur at the inside of the rear lens cap resulting in forming droplets that fall onto the lens.
Though I myself consider this far fetched. And even then they would not necessarily leaf marks on the lens element.

 

[Alan Gales]

It sounds like one of the mysteries of life. It's like washing and drying socks. An even amount goes in and an odd amount comes out. Where does that sock go?

 

[John Koehrer]

It sounds like one of the mysteries of life. It's like washing and drying socks. An even amount goes in and an odd amount comes out. Where does that sock go?

The fourth dimension along with the springs that have shot over my shoulder in the past.

 

[Theo Sulphate]

Have you ever tried putting an odd number of socks in the washer? It's the obvious solution. Duh. An even amount comes out then. Just gotta use your noodle.

Yes, but you've still lost one sock and even then none of the rest match.

Regarding the lens spots: I've seen this before on lenses and they do clean off without leaving any other spots or damage to the coating. However, I've seen this numerous times on the mirror of one of my Hasselblads. It also cleans off. I monitor my camera room's humidity, and it's usually between 40%-55%. I don't think it's fungus. Maybe a "pre-fungus"?

 

[GRHazelton]

To reside along with my nail sets, small screwdrivers both Phillips and straight, Allen wrenches, etc. Maybe the Borrowers have a secret cache of them?

 

[Xmas]

Tooof fairy?

 

[Tom Taylor]

Thanks for the replies everyone.

That is was "pre-fungus" as suggested below was also my estimation when I first saw the spots. I also received in my inbox a detailed explanation from another apug member that the spots were the result of micro condensation which made a lot of sense and I am replacing the two or three tiny packs of silica desiccant with an appropriate volume of fresh desiccant.

Thpmas

Regarding the lens spots: I've seen this before on lenses and they do clean off without leaving any other spots or damage to the coating. However, I've seen this numerous times on the mirror of one of my Hasselblads. It also cleans off. I monitor my camera room's humidity, and it's usually between 40%-55%. I don't think it's fungus. Maybe a "pre-fungus"?

 

[AgX]

That is was "pre-fungus" as suggested below was also my estimation when I first saw the spots.

Lens fungus is typically seen inside a lens.

 

[macfred]

Lens fungus is typically seen inside a lens.

Normally yes - but those come from outer space … http://www.rense.com/general8/mir.htm