So I bought a bad lens on eBay, now what?

BeardedManMatt wrote:

Let's get it out of the way, eBay was a mistake OK let's move on.

I was looking for a 30mm 2.0 and I decided to go down the eBay path. I found a used bundle with NX10, 30mm, 18-55mm & 50-200mm, I won that for about $15 more than buying a new 30mm. My intention was to just sell the NX10 + 18-55mm together, and sell the 50-200mm as I already have one, that way I would have a 30mm really cheap.

The 50-200 is mark I and my III is much sharper around the edges, so that can go, it's in OK condition.

The 30mm has a tiny scratch on it which only becomes faintly visible at f/8 as a small circle and by f/22 it's a grey dot- easy to remove with spot tool. I had to be at 100% to see it on an all white background and I didn't buy a fast prime to be shooting at small apertures anyway.

Which brings me to the 18-55.. I had my magnifying goggles on (think Honey I Shrunk the Kids) and noticed the glass has come away from where it's supposed to sit, I never saw this without the goggles though. I can actually gently push on any side and it will go in with a gap like this pushing the other edge back into the correct position.

You can see it starts below the 58 and goes right the way around until about the 5.6 mark. I'm thinking they're dust particles on the inside, although a few of them might be scratches. Now is this a lens in bad condition or just a bad design by Samsung? I've never really seen good things about this lens and the whole thing feels pretty cheap from the glass to the plastic mount to the focus ring. Also I've never seen a focus ring as loose as this one, it turns a lot more freely than any other NX lens I've used, still works but it feels weird..

Is this a common thing amongst these lenses or is this lens a dud? I'm not really keen on going through the process of returning them and losing the 30mm, but then I don't want to sell a dud lens on to somebody else.

Looking for any insights here, thank you.

This is very interesting because I had that same eBay listing on my watch list but decided not to bid.  The reason I was considering it is that my own NX10 has a broken latch on the battery door.  It isn't a big problem.  I just tape it shut but it makes changing the battery a little inconvenient.  Anyway, I decided it would be better for me to put the money towards upgrading, perhaps to the NX50 if that is released soon.

I already have version 1 of the 18-55 and of the 50-200 and did have the 30mm and 20mm but sold them some time ago.

Now to your questions:  Firstly, the focus ring on my 18-55 also turns very freely but as it focuses by wire it doesn't have to physically move anything, so I think that is normal.  I am fairly sure the crenellations visible in your pic that others commented on are those of the focus ring, not a filter.

I find the 18-55 quite useful and much better than the plastic build suggests.  Its OIS is also very effective.

When you push the plastic "title ring" or whatever the ring with the lens description on is called, are you sure the front lens element moves too?  If so, the lens is defective. There may be a simple DIY fix but I wouldn't accept it anyway.  If it is only the "title ring" that moves, that wouldn't affect the lens performance.