Here's a paragraph I pulled off of a site from doing a Google search:
"The main purpose of using neutral density (i.e., ND) filters is to reduce the amount of light that can pass through the lens. As a result, if a shutter speed is kept the same, after adding a neutral density filter, a larger aperture must be used to obtain the same exposure. Similarly, if an aperture is kept the same, after adding a neutral density filter, a slower shutter speed must be used to obtain the same exposure."
In addition, I think I read somewhere that a ND filter is also used when you have situations where you have a very high amount of light and also shadows in your shot and what to make the exposure more even between the light and dark areas. So, I think what the filter does in this situation would be to limit the intense light coming in to the camera sensor, and this causes the camera to expose the darker areas more. Not sure however if this is right. |
