ND filters

[raider2727]

help i have got 2 ND filters which arrived with a lens i brought.
never used them before and not sure what they are used for, they are a Tiffen 0.3 and a 0.6
i do like using filters so feel sure i would make use of them if i knew what they did, i know they reduce light but is that the same as using exposure compensation on the camera?

 

[Garry Edwards]

Yes, they reduce light by 1 stop and 2 stops respectively

 

[raider2727]

ok so i am probably just being thick but are they needed if i can adjust the exposure on the camera and in what situations would they be used?

 

[Carl V]

ND filters are used to decrease the amount of light entering the lens, for example, if you want to use a long shutter speed for a desired effect or use a large aperture, in situations where your ISO/ASA setting wouldn't normally allow. With 0.3 and 0.6, your built in meter should already compensate when using these filters as they are not especially strong. But if you were to use say, a 10-stop filter, I'd take a meter reading first, and then add the appropriate exposure once you put your filter on.

Just reading your original question, it's not the same as altering your exposure compensation dial. The purpose of these filters is to allow you to create longer exposures without over-exposing your shot.

 

[HoppyUK]

Those ND filters are so weak that I honestly can't think of a use for them. Used together, three stops is maybe handy if you want to use a low f/number for shallow depth of field when the light is very bright and you can't get a high enough shutter speed. This might be the case with an old film camera. You could shoot at f/2 instead of f/5.6 perhaps.

To get really long shutter speeds in daylight they are just not dark enough - you need six stops or ten stops for that.