Possible Duplicate:
What are neutral density filters and how do I use them to create long exposures in daylight?
I like to take photos of motorsports and high speed action. Sometimes I use really fast shots, like 1/4000s, but sometimes I like to take a slower shot to get some 'movement' - say 1/500s or slower. It helps when a car is sliding through a corner, for example!
At the same time I like to use a big aperture to achieve shallow depth of field to really make the subject stand out. Especially if I'm trying to capture some motion, I don't want the subject to have some motion blur and the background appear relatively sharper. So I often have the aperture open to 3.5 or 2.8; I'd like to have the option to open it even more.
The sun is often very bright here, so I find that slower shutter speed and higher aperture lead to over exposed images. The camera is on ISO 100 but it's still too bright!
So my question is how can I achieve the motion blur and shallow depth of field that I'm after in bright conditions, without being overexposed?
