low light situations at iso 160 [Ameland]

[gordo1507]

here is my flickr-album of my journey to Ameland an island in the netherlands. especially at the shot in the forest where I put the area above up, you can see how iso 160 works on shots on the 550d!
maybe you can tell me, how you think this iso stop works well or not, my opinion is that it works very good by reduicing the noise!
http://www.flickr.com/photos/gschroedter/sets/72157631365629524/