'Crystals' inside my Canon EF 100mm Macro USM Lens

photonius wrote:

SarahBK wrote:

Hello all,

I've been a long reader of this forum and have joined a short while ago to be able to comment on articles. I thought today I'd create a forum post in order to get some advice regarding a topic the internet, including this forum, seems to have no answer for.

Some months ago, on a flight back, I was using my Canon EF 100mm Macro USM lens to take photos of these snowflake-like crystals that were forming in between the glass of the plane's windows. The following is one of the photos I took:

The crystals that formed in between the two layers of glass of the plane window during the flight.

Once I got back home and was checking to make sure my lenses were all ok, I noticed very similar looking crystals on the inside of my lens, mostly around the peripheries. They were definitely not there before, and I was never in freezing cold weather (home temperature was above 30 degrees celcius, and I'd left Scotland which was above 15 degrees celcius). People I have spoken to suggested it's fungus, but I doubt fungus would form within a day and look like that - but to be very honest I've never seen lens fungus before.

Here is a picture of what they look like today, months after they formed, and they haven't really changed. They are difficult to see unless angled against the sun, and I couldn't get any closer since that's my only macro lens, so excuse the quality. You can make out their shape though:

The crystals on the inside of my Canon 100mm macro lens.

Not clear from the picture is exactly where they are - but I can tell at what level they are when I handle the lens. Hence, I tried to illustrate this on a diagram I found showing the lens' elements. They seem to be on the element right behind the front one.

(picture courtesy of: http://www.markusehrenfried.de/photography/canonef100mmf2.8.html)

Although it seems to defy the laws of physics, I'm convinced they are water-based crystals (you would expect them to melt instantaneously if they were ice...). What confirms this wacky idea is two things:
a) They look exactly like those crystals that formed in between the glass of the plane window (and coincidentally, between two layers of glass in my lens too)
b) When i take the lens out into the sun, tiny droplets of humidity form around the crystals - signifying there is moisture in there.
So my questions to you are:

1. What do you think those crystals are? Have you ever seen anything like them?
2. What can I try do to remove them? (Probably taking it for servicing would be the best idea; although I did take it to the Canon distributor in my country from whom I bought the lens and they had no idea what they were. Servicing would probably be ridiculously expensive and would take a long time).

I'd appreciate your suggestions, ideas and advice. While they don't seem to be affecting image quality currently, I presume it's because I use it on a crop sensor so perhaps these crystals are too peripheral to be a problem. I do hope to use this lens on a full frame in the future, where they may actually become problematic...

no matter what it is, you should get it cleaned professionally as quickly as possible. Based on the latest picture by brightcolors it does look like fungus (although I was initially also thinking of salt crystals, but where would they come from, some salt water leak, maybe not impossible given you are in malta, and could have used it near the sea)

Yeah it is more convincing than anything I'd seen before.

It's unlikely to be salt though, because this happened while in Scotland and I never went next to the sea there. But to reply to your other comment earlier, yes there is humidity around the crystals in the sun - don't think it affects pictures but never confirmed it. I do have a crop sensor though. I can take another picture to try show this if you're curious.