Neutral density vs. Polarizer: what's the difference?

[Hatem Eldoronki]

Examples/explanation would be appreciated..

[Tapeman]

Neutral density filters are like sunglasses for your lens. They reduce the amount of light and they do not affect color. They come in varying strengths. They are usefull when you want to slow down shutter speed.

Circular polarizers also reduce light but their main function is to reduce reflections from the surfaces of what you are shooting. They are especially usefull around water. They also make skies bluer and clouds more dramatic.

[Scottes]

CPLs can often be used as NDs if that's all you have. You may just have to spin the CPL so it doesn't polarize the light as much - if you want the glare that is. CPLs generally change the light by 2 stops - it's often nice to have a set of +1 +2 and +3 NDs.