Spots on F.Zuiko

[thuggins]

It is the time of year when the various lenses get broken out for their sun bath and inspection. A couple of the 38f1.8 Pen F lenses are showing spots on or about the rear element. The spots are very precisely round and some show as a concentric ring.

The attached images are out of focus, but are as good as I could get with the phone. In reality the spots are much sharper than that and not fuzzy at all. Any thoughts on what they may be?

 

[David Lyga]

Might be internal fungus (I am assuming that you cannot wipe the spots off externally) but do not know for sure. I do not know how or where the lenses were stored: that could be a component in this dilemma, especially if they were stored in a damp, dark place. - David Lyga

 

[thuggins]

Thanks for the thoughts. The lenses are stored in the dark, but in airtight desiccant filled containers in an air conditioned/heated room in Dallas, TX. Usually about once a year the lenses are set out and aimed at the direct sun for at least several hours. I.E. short of being in the middle of the Sahara it is about as inimical to fungus as I can make it.

Also, this does not look like any fungus I've seen or heard of. There are no tendrils or "lacework", just very precise spots, some with a halo around them.

 

[David Lyga]

Again, are the dots internal or external. Look closely with a magnifying glass, if necessary, at the very glass surface. - David Lyga

 

[AgX]

Condensation marks

 

[ciniframe]

I've solved all these problems by not looking through lenses in bright sunlight.

 

[JW PHOTO]

I've solved all these problems by not looking through lenses in bright sunlight.

Very smart! I bet your pictures can't see little dots either can they? John W

 

[Fixcinater]

I've seen fungus started/helped along in its mission to kill contrast and obstruct sharpness by dust particles. You may be seeing the very beginning stages.

I would break them out more often and get them cleaned up ASAP.

 

[ciniframe]

Very smart! I bet your pictures can't see little dots either can they? John W

Although I live in the damp Pacific Northwest amazingly I've seen fungus on only one of my many lenses. Fortunately most of my lens selection, with a couple of exceptions, were very cheap. Cheap like in the $5 to $50 price range, heavily biased toward the low end. What I have noticed when examining lenses under bright sunlight is lots of dust, a few larger chunks of who knows what, flakes of internal blacking maybe, and almost always present, light 'cleaning' marks. If you dwell on this it can drive you mad so I just ignore it. I can see however the OP's concern with regular inspection. As I understand it fungus, in it early stages at least, can be arrested and cleaned off sucessfully.