For me the most important filter I have in my camera bag is the circular polarizing filter, this is because of the many uses this for this filter that can help enhance your images. First, and what most people use this filter for is to help create a more dramatic look to the sky by deepening the blue and brightening the clouds. Second, is to take out the reflections in surfaces such as glass or glare on shiny surfaces like a wet green leaf. Lastly, you can use it to slow down your shutter speed by up to 2 stops. If you are shooting a stream or moving water and your scene is a little to bright and you cannot get a slow enough shutter speed, try putting on your CP filter and using it like a ND filter. The way a CP filter works is by attaching it to the front of your lenses and turning the filter till you see the desired effect thru your viewfinder. For maximum effect it is best to have the sun directly behind you or over your left or right shoulder, not directly in front of you.
Lens Used: SP24-70mm F/2.8 Di VC USD
Focal Length: 24mm
Shutter Speed: 1/80th