General Filter Questions

[hobbes28]

Hello. I am wanting to purchase some Neutral Density filters. I have a Kodak 6490 that I have been using the most and the smallest aperature is an f8. I would like to take some slow speed shots in the daylight but currently can't with this camera. I have read that you can get ND filters to artificially step down the aperature but have never seen any clear cut charting. My 35mm goes to an f22 and I have used that a ton but would just like to take some in digital. Please help me!!

 

[ksmattfish]

Neutral density filters are like sunglasses for your camera; they block light intensity without affecting color. They come in different densities, and are usually labeled with a "filter factor".

Filter factor is the amount of extra light you'll need to make up for the filter. A filter factor of 2, means twice as much light, or 1 stop. A filter factor of 4 means 4 times as much light, or 2 stops. A filter factor of 8 means 8 times as much light, or 3 stops.

Remember that a stop is a doubling, or halving of the amount of light, so 3 stops is 2x2x2=8. 4 stops would be 2x2x2x2=filter factor of 16. You can find an easy to use chart that converts filter factors into stops at any filter manufacturer website such as Tiffen or Hoya. You might want to check them out anyway, as I might be wrong on how I'm converting the filter factor to stops, it's been a while....