Neutral Density/Stop Down Filter

[feRRari4756]

Hey guys in Scott Kelbys book he mentions to use a "stop down filter" so you can use long exposers during the day. is this the same thing as a Neutral Density filter?

and is this a good one?

Cambron 52MM ND4X NEUTRAL DENSITY Camera Lens Filter - eBay (item 380094000555 end time Jan-31-09 13:37:00 PST)

 

[Johnboy2978]

is this the same thing as a Neutral Density filter?

yes

and is this a good one?

no. Look at B/H and you probably want to shoot for B+W, Hoya, Tiffen (in that order). You may want a couple at various different stages such as a 0.6 and maybe a 1.8 depending on what you are doing. Remember if you are putting crappy glass in front of a decent lens, then you are cutting it's optical performance. If that doesn't matter to you, then ebay is fine. Also, you would be well advised to get filters to go on your largest diameter lens and then use step rings/filters to fit the other lenses of smaller filter size to avoid buying the same filters for each lens.

Neutral Density factors
• ND.3 (exposure adjustment = 1 stop, reduces ISO 1/2)
• ND.6 (exposure adjustment = 2 stops, reduces ISO 1/4)
• ND.9 (exposure adjustment = 3 stops, reduces ISO 1/8)
• ND 1.8 (exposure adjustment = approx. 6 stops, transmits 1% of light,)
• ND 3.0 (exposure adjustment = 10 stops, transmits 0.1% of light)
• ND 4.0 (exposure adjustment = 13-2/3 stops, transmits 0.01% of light)
• ND 6.0 = (exposure adjustment = approx. 20 stops)