Carl Zeiss Lenses makes some of the best glass that money can buy. Well now they are making some filters to work seamlessly with their lenses. The polarizer caught my eye recently. It will set you back a few pennies but may be well worth the expense. The 77mm Polarizer will set you back around two hundred smackers. Here is a rip from the Carl Zeiss Lenses website.
“Circular polarization filters from Carl Zeiss can minimize reflections on non-metallic shiny surfaces (e.g. water, glass, plastic, paint or leaves). Reflections are avoided, higher color saturation and richer contrast is achieved. Haze is eliminated in landscape photography, the sky is bluer and better color separation is enabled. The effectiveness of a polarization filter depends on the taking angle to the reflecting surface and the position of the filter. Therefore, POL filters are equipped with a screw mount. This allows configuration of the desired filter effect before taking a picture with an SLR camera. Visible light is reduced by 1.5 – 2 EV (filter factor 3-4) depending on the position of the filter on the screw mount. On all camera models, circular polarization filters ensure that TTL exposure metering and the autofocus function work properly regardless of the filter rotation.”