Help - fungus or haze?

[Shac]

Hi - Any opinions about whether this is haze/fog or fungus.
It's a black Canon 100/3.m LTM lens and the problem is on one of the middle elements.
Thanks in advance
David

 

[Sonnar Brian]

That element is notorious for haze and etching. It looks like someone tried to clean it, and haze came back.

If it is for sale- needs to be super-cheap.
If you own it, the only way to find out is to open it up and clean it.

The two rear elements are held in place with a retaining ring and spacer between the elements. Mark the outside of the elements with a marker before removing, easy to insert backwards.

 

[Shac]

Thank you Brian - most helpful.
So would etching be due to fungus or "just" haze in your experience?

 

[Sonnar Brian]

The etching is due to the type of glass used for that element reacting to the lubricants.

I just finished cleaning one "Again", after 18 months. When I get time- I need to tear the focus down, remove the lubricants, and relube.

 

[Shac]

Brian - thanks again. I've checked with my local repairman (ex-Canon) and he's willing to try cleaning it. So fingers crossed.
Cheers
David

 

[02Pilot]

Even if cleaning is not totally successful, a good deep hood should make it usable. I have a 34-37 step-up ring and a large 37mm hood on mine.

 

[Shac]

Thanks for the suggestion 02Pilot. I have the official hood and will see how it works.
It goes in for cleaning tomorrow motning

 

[Moto-Uno]

As a Burnaby resident , I'm kinda curious where you're taking it for repairs ? Peter