I think there's some confusion about filter types going on here...

ND = Neutral Density - the goal is to reduce the overall amount of light reaching the sensor, evenly across the spectrum, i.e. NEUTRAL. The idea is to allow a larger aperature under a given light condition, particularly a bright daylight situation. IOW, while the camera stock out of the box may auto adjust to bright daylight, it may have to move out of the "sweet spot" for the lens/shutter, and basically putting a dark sheet of glass over the lens can bring it back into the sweet spot.

Polarizers are something different, and while they do block light, they are designed to block it at a specific angle, reducing glare/relections/haze, thus why polarizers have rotating elements - you can change the angle of the effect - stack two together, and you can actually block ALL light...

UV filters are supposed to reduce INVISIBLE light frequencies and are often used the same as a "protective filter" which is just there to "protect" the lens from scratches (and add two more opportunites for the dust bunnies to attack!)

By and large, most consumer cams automatically try to adjust for the best picture, some like the HF-S give you manual override and more creative control like a big cam would.

Neutral Filter
 

To add a bit more to what has already been said one purpose for use of neutral density filters in addition to hitting the sweet spot for a particular lens is to add flexibiltiy in terms of depth of field considerations. Smaller chip size makes it more difficult to use depth of field in a similar way to film. One way around this is to try to adjust exposure to keep the lens aperature as wide open as possible. In bright light this is where neutral density filters can be very useful.

Mike

Thanks guys,
it is a bit clearer, i guess i will wait to do some test with the cam before buying a neutral if i don't need it

cheers

Built in ND HF10?
 

i have the Vixia HF10 not the HFS new models. I can not find the built in ND filter discussed in this thread. is it a feature only in the newer cambers?

Based on what I read, it does not sound promising to use the Cokin A system with ND filter?

any thoughts?

Rick - there are no filters 'to find', but if you zoom to full telephoto have tha camera in manual, use a bright Maglight (say) and look down into the lens you might well be able to see the internal ND filters moving in and out of the light path as you vary the iris control.

Cameras have had this for many years. My Canon 310XL used internal ND, and that was a 1976 model.

tom.