This globular inclusion lives behind the rear glass of an otherwise nice M 50/1.7.

[j2photos]

That can be cleaned very easily if it hasnt destroyed the SMC.

[AquaDome]

Do you think so? I assumed it was separation bubbles in the cement between the lens elements.
I tried to get it to show up in a photo. Pictures of a white wall at f8 showed a hair-like line in a few. It turned out to be a hair on my sensor.
So far, it works as it should. It was included with some other gear in a camera bag from eBay.

[j2photos]

The rear glass just unscrews, depending on where the defect is as it is hard to tell it may be very simple to clean, once you get the rear element out it also unscrews(It can be VERY hard)

I used to refurb lenses for people and I created a dust free work area by taking a large tupperware container, cutting holes in each side and taped rubber gardening gloves, or heavy rubber dish gloves into the holes cut out a large square in the top and silicone in a nice piece of lexan. the font element is easy to remove as well you can see the two notches on each side of the element with a special wrench.


here is a nice write-up on dissasembly.

Shooting with a Pentax K10D: Cleaning from fungus: SMC Pentax-M 50 f/1.7

[AquaDome]

That sure looks like the same crud.
Is there a particular brand or size of spanner I should be looking for?
Are there any issues with aligning or centering the optics? I don't know what voodoo they perform on these things when they calibrate them.

[j2photos]

I prefer Facom spanners but they tend to be on the pricer side. Alignment isnt a huge issue as the elements will sit right back in their seats. If it is fungus hit it with some vinegar and that will make sure it doesnt come back.

[AquaDome]

Thanks a bunch!
I assumed it was a gonner, as did the person who stuffed it in the camera bag being auctioned, I'm sure.
I ordered a spanner. We'll see what happens when it gets here.