Okay, before anyone gets all technical and huffy, let me say this is not the sort of in-depth camera tests that hardcore phone and camera websites get up to.
As detailed in my hands-on, I got a loan of a Lumia 800 for a couple of days during Nokia World 800.
It came in a retail box, but I can't tell whether it was proper production line or pre-production. If nothing else, the camera button was a little wobbly, and I don't know anything about the state of the camera firmware etc.
Still, with that explanation out of the way, I was surprised when comparing the Lumia 800 with its 8MP Carl Zeiss lens to the Sony Ericsson Xperia Play (the only phone I had with me), which has a fairly standard 5MP lens. All images were shot with the default camera settings and - obviously - not altered in Photoshop.
Starting off with a view from the Excel conference center, the Lumia 800 image (bottom) is obviously using a wider angle, but looks rather washed out in terms of colours, and there's also some bloom around the window. (Note, these aren't the full scale images, but scaled down to the column size).
The second comparison shot isn't so useful as the distance from the cup is slightly different in both cases (no expert me). However, aside from the soft focus in the Lumia 800 - perhaps I'm too close to the cup/can - the strong orange colour cast is obvious.
Yet it's not all bad. The following aren't comparison shots, but the focus and lighting on these glasses is excellent, while Peter Vesterbacka from Rovio (aka Mighty Eagle) - taken on full zoom (he was about 4m from me) - is in focus, even if the colour cast is somewhat warm and there's plenty of bloom.
One issue I can think of is that camera phone images are designed to be shown on-device, so different screen specs may have something to do with it. Obviously, Nokia and Sony Ericsson are unlikely to share screen specs.
Still, it will be interesting to do more tests when we get our hands on a model for a longer period of time.