Question about ND filters...

[Adam Hicks]

Today I found myself wanting to shoot a scene while allowing cars and people to show motion blur. Even at ISO 100 I could not get the shutter time long enough to get the shot due to available daylight (in Tv, it would bump Aperture to 32, but still too fast)

I haven't used an ND filter but I'm assuming it would help with this situation. Is there a formula or number which would tell how much it will stop the exposure down?

THanks!
Adam

[wolf]

Here is some info for you on the Filter Factor (http://www.photofilter.com/neutral_density.htm).

[Adam Hicks]

Ok, so will this let me do what I want? If I wanted to shoot in daylight at f11-f13 with a shutter time of 1" I assume I'm going to need a pretty darned dark ND filter. Guess I'll pick a few up and see what works best...

Thanks,
Adam

[Persian-Rice]

There are differnt levels of dimming, then there are graduated Neutral Density filters aka ND Grads. I have read about adjustable ones as well, but are extremely expensive.

You can also stack filters.........etc etc

[steven]

I have purchased ND is three different levels, 1 Stop, 2 Stop and 3 Stop.
You didn't mention what you starting shutter speed was but with a set of these you can stack them for a total of 6 stops and that is very dark.