I'm coming a little late to this discussion, but a grim pneumonia has sidelined me for ten days; it's the first time I see this thread. As the seller of this lense I feel I should comment here as well.
Firstly, Anders, thank you for not blaming me of having concealed a flaw in this lens. I have not.
I can not say though whether or not the impurity in the lens was there already when I owned it, because I have not scrutinised the lens interiors at microscopical distance. I presume it was not there, because the way I check my purchases on arrival, I normally pick up irregularities or in this case an impurity in the lens, if that is what Anders has identified in the Nokton. My presumption hence is that any vibration (airplane? train?) or even a kick to the parcel in transit has moved the "debris" within sight.
Does the "debris" negatively impact image quality?
With extremly high probability - No. The slides I did with that lens show no irregularities at all; and I would be surprised if even at a stellar zoom-in level any such could be identifiable. From a technical view, I think a "debris" of the size shown in the picture can not possibly go into the imaging of this lens; the size of it is most likely beyond the imaging capability of its formula. I even doubt that a single piece of dust would be visible in a very very wide lense. My practical experience with old and dirty SLR-lenses, as well as clean 35 and 24 mm lenses with dirty (really dirty!) filters on it is that not even harshly unclean surfaces, also under flare-prone conditions, impact image quality on the level I use to scrutinize it. In my humble oppinion, the impact of this "debris" is a rather on the cosmetic side of things.
What to do?
Nothing. The impurity will probably go away as it came: Through vibration or a gentle kick. I would in no event dare to open the lens. If this is a warranyt case at all (doubtful, because not obviously a "defect" as defined in the warranty), I would not claim the warranty, because the case in my view does not justify the down-time and the transfer costs involved.
What I would do is rather to shoot shoot shoot with the Nokton - this will re-establish peace of mind quickly. Anders, that's what I sincerely hope you will be able to very soon!
Happy shooting,
Gerold
