No filter. Just a cheap camera. The sky came from another photo I took in the UK. You must have Photoshop Elements or similar to do this sort of thing. The photo has been edited to avoid buildings leaning in. You must have an editor to get the most out of your photography. Optimise colours, remove unwanted artifacts. Go to:- http://www.panoramio.com/user/1849922 to see some of my photos from around the place. Many are on Google Earth. Great fun!