What's problem with brand new lenses ? ballon or dust inside

[check_box]

I had bought a brand new lenses from ebay seller, I just unbox and use this lenses ONE time. Yesterday, I used a flash light to check, I saw something inside glasses lenses.



Is it a brand new lenses ? What I saw inside lenses is dust or balloon of glass

[Lightshow]

That would be unacceptable for a new lens from a store, older used zoome are a slightly different story, some dust is normal, but shouldn't have lots, as that's a sign of being stored without caps.
A flashlight can turn a relatively clean lens into the dirtiest lens ever, as it highlights every speck more than it would normally show.

[check_box]

[visualopsins]

I see some dust on the rear element. I think light to be very powerful to show what in normal light cannot see. Inside lens I see light reflections from the lens elements -- are these the 'balloons'?

[ForenSeil]

No bubbles, modern glasses are generally degassed by vacuum and/or ultrasonic sound while liquid to avoid any bubbles.
You can find bubbles in old lenses, also from first party makers, but generally not in modern photographic lenses as far as I know.

I had several, also used, modern CZ lenses, and not a single one looked that dusty.
Actually I think I had 60 years old lenses which were less dusty, I think that's not a really "new" one.
Maybe a demonstration model from a shop, already couching in a shop window or a desk or a some time?

Anyway, it looks like most dust is on the outside of the rear element, I guess stored for some times without rear cap.
Can be easily cleanen easily without opening I guess.

I would clean it from outside with a good microfibre towel and/or a blower and if it stays that dusty I would try to send it back if price wasn't very low.