Thanks Emmanuel. I have followed your advice and the render is indeed the same:

Blog:
http://www.sweethome3d.com/blog/images/ChristmasLights/ChristmasMulticolorLights.png

Mine:
https://www.dropbox.com/s/vkrqgkw5w34u3qz/ChristmasLightsv3.png?dl=1

On the forum I have seen some crazy crisp/sharp ...

Here is one without the lights:

According to the blogpost it should be on Or I misread it. But still, that's just a light thing. The objects are still not sharp, for instance the bike.

I have noticed this in the past, but with the latest blog (about the lights/soft shadows/Christmas tree) I thought lets try it again.

Using the same settings as the example: 400x225, 16/9, best quality at 25-12-2014 16:00 with ceiling lighting it doesn't make as crisp pictures as the one on the ...