Using a Neutral Density Filter

[Andy]

I am preparing to hike Yosemite's Half Dome in a couple of weeks and want to be well prepared for the photo opts at the top of the mountain. I plan to bring a polarizer and neutral density filter for my Pentax 67 II's 45mm lens and would like to know when I would choose to use the polarizer vs using the neutral density filter. I am pretty new at this and don't want to blow it since it is a greuling hike to the top and it will probably be the first and last time I hike it. Any info is appreciated.

[Georgews]

All a neutral density filter does is cut down the amount of light getting through your lens. Use it only if you have a very bright day or if you are deliberately trying for long exposures for things such as cotton wool effect on flowing water.
The polarizer can cut down reflections and darken the sky to a nice deep blue colour. Good for cutting out water reflections too (but will not cut out reflections off metal)
Rotate the polarizer until you get the desired effect
Make sure you have a UV filter to help cut out general haze also
Have fun