Well, I'm assuming you're using an R72 filter on your lens. You must use a tripod, and focus & set up your scene first before attaching your filter to the lens (you can't see much, if anything after the filter is on). Set your ISO speed to around 1600 (you may want to adjust this as you please, but try 1600 to start). Set your camera to all manual settings. Open your aperture as far as it will go. Preferably with a remote shutter release, release your shutter for say 5 seconds and check the result. You'll have to experiment with this, with more or less time depending on the result you want. I hope this is of some help to you Ayhan!