[Jome]

My two cents:
1) possibility of botched re-cementing = 0.01%
2) possibility of badly wrong cleaning = 1%
3) internal stain = 10% (given the regular shape, it could have been a large drop of heavy mineralized water that got inside the lens and evaporated, leaving a residue)
4) fungus = 20% (doesn't look like the usual fungi, but you should try to take more pictures, with different lighting and at different angles)
5) separation = the most likely, though what I can see in the picture reminds more of Canada Balsam failure, which is impossible, given the age/maker of the lens. Opaque semi/circular areas or star-like spots are what I'd expect.

In my limited experience, fungus cleans nicely on SMC coating. So it's well worth a try. To go through the lens from the front you probably need a rubber cap of the right size to unscrew the beauty ring and get access to the screws.
Incidentally, the last fungi I tried to clean didn't clean at all One was a case of separation in an internal group of a late "silver" FA zoom, and the other (single coated achromatic doublet from a Novoflex 640mm lens head) left marks, quite visible at an angle.
Proceed with caution, taking pictures with the phone, if it's the first time you attempt to dismantle an AF objective.
F/FA macros are great lenses, and most times what affects the eye doesn't really affect the pictures. Personally I'd try to see what it is, but I'm not sure it would be the most sensible decision


BTW, for what you paid, you got A LOT. Even if you find some cement separation in your macro.
I own the F 50mm and the FA 100mm. Those were great macro optics, still more than fine on high res FF sensors.
Let's not forget that in the package you found one of the best Pentax MF zooms.
Didn't check if it fringes on the K-1, but I'm sure that at its sweet spot it can still give plenty of fun... and lots of sharp pictures!
A pity it's a little bulky/heavy, but the build is impeccable

Thanks a lot for the infos.

[Jome]

I removed the Beauty ring to try to see better inside the lens (while waiting my JIS Screwdrivers)...

Cleaned a little the front lens (some little dots of coating are missing)...

Used my dust blower to remove some... dust from the front part of the lens.

Used again my dust blower everywhere around the lens (behind the beauty ring)...

And now...

Haze has drastically diminished (still there but not so much)...

It seems that it was only some dust + condensation...

Wohoooo!!!!!!


You know what? I'm happy!!!

I Think This Is The Beginning Of A Beautiful Friendship (between my K-3 and thePentax-F 100mm F2.8 Macro).

Anyway, many thanks to all of you, you really rock!!!

Now I will carry on to post some pictures taken with it in some places of our fantastic forum.

Take care.

Joël

[cyberjunkie]

Haze has drastically diminished (still there but not so much)...

It seems that it was only some dust + condensation...

It could just be simple condensation.
I completely forgot that you just got the lens.
Air transport is quick, but comes at a price: huge differences in pressure and temperature.
If you don't live in a very humid place (as I do ) the lens should have recovered from condensation in the meantime.
As a general rule, if you get a new lens it's better to inspect it immediately, and f you see any suspect condensation, I'd seal the lens inside a clear plastic bag, with a bag/box of working dehumidifier.
I have silica gel bags, run through a electric oven with the door not shut, silica gel plastic boxes that change color when crystals can't absorb water anymore, and large boxes (with different crystals) that I use when I leave Thailand for a while, leaving my lenses inside a large plastic box.
If a lens has humidity in it, and there are fungal spores, the only way to avoid any chance of fungal growth is to expose the lens to UV light. A table lamp close enough should work, but I have a cheap UV lamp with E27 attachment that does its job much quicker

[aslyfox]

. . . Now I will carry on to post some pictures taken with it in some places of our fantastic forum.

Take care.

Joël

please do that

[Jome]

It could just be simple condensation.
I completely forgot that you just got the lens.
Air transport is quick, but comes at a price: huge differences in pressure and temperature.
If you don't live in a very humid place (as I do ) the lens should have recovered from condensation in the meantime.
As a general rule, if you get a new lens it's better to inspect it immediately, and f you see any suspect condensation, I'd seal the lens inside a clear plastic bag, with a bag/box of working dehumidifier.
I have silica gel bags, run through a electric oven with the door not shut, silica gel plastic boxes that change color when crystals can't absorb water anymore, and large boxes (with different crystals) that I use when I leave Thailand for a while, leaving my lenses inside a large plastic box.
If a lens has humidity in it, and there are fungal spores, the only way to avoid any chance of fungal growth is to expose the lens to UV light. A table lamp close enough should work, but I have a cheap UV lamp with E27 attachment that does its job much quicker

Hello Cyberjunkie,
It was a very fast delivery (it arrived less than 24 hours after the seller posted it). I found it in the same country (Switzerland). Anyway, it was the first time I had this experience (OK, only 2 lenses came by plane -from the marketplace).
I have to find an UV Lamp (need to find someone that can lend me one).
As soon as the JIS screwdrivers come, I will check if it is easy to dismantle the two first lenses from the front to correctly clean then dry them (lot of silica bags around).
Thanks for your advice.
J.

[Jome]

please do that

Sure, thanks for encouragements!