Is this a case of lens element separation?

[diddy]

About half a year ago I bought 2 Tamron SP 35-200mm lenses and both had a bit a funny looking rear element. As it was the same with both of them, I thought maybe it is just the way the elements are cut. Recently though I stumbled upon an article discussing lens element separation with older lenses. Now I got quite worried again. So can someone please tell me if this is really lens element separation:
The picture is available on the dropbox website: https://www.dropbox.com/s/a9zjl4di1vg7aaw/IMG_0015.jpg
Here the lens diagram as shown on adaptall-2.org:

There doesn't seem to be any impact on the pictures I take with this lens.
Thanks,
Diddy

[luisalegria]

No, from the picture it just looks like damaged coating.

[diddy]

Thanks a lot Luis for your reply! The thing is that this "discoloring" is not on the outside. If you look at the diagram above, it is possibly where the last glass element meets the second last one. Or did they apply multi-coating on the inside of the elements as well those days?

[luisalegria]

Coating would be on all air surfaces as far as I know.
Cemented surfaces would not be coated, but I may be wrong on that.
If there isnt an effect on performance then I wouldnt worry about it.

[diddy]

Ok, thanks, I relax then

[fermy]

Hard to be sure based on that picture. Separation does not mean that you should bin the lens. I have Canon FD 35/f2 that developed separation, I didn't notice any decline in performance except flare in very particular situations.

[gmonkman1]

yup....looks like lens separation.
but just like fermy says....use it until you don`t want it anymore.

[diddy]

Thanks a lot for all your feedback! In general I am quite astound by the optical quality of this super zoom and yes, as you said, I should just enjoy using it!