Some time ago during one of my $2-max-shopping-sprees where I single-handedly strengthen the economy and sustainability of eBay, I purchased an ND8 filter. An ND, or Neutral Density, filter is basically sunglasses for my lens. Similar to reducing the aperture (ie. increasing the f-stop), an ND reduces the amount of light that reaches the camera’s sensors, allowing you to leave the shutter open for longer periods without over-exposing the image.
Technically, the value in ND# represents the equivalent fractional lens area to block out the same amount of light. So, an ND2 would be 1/2 the lens area, analogous to 1 f-stop reduction in aperture, letting in only 50% of the normal light. Similarly, an ND8 would be 1/8 the lens area, analogous to 3 f-stop aperture reductions, letting in only 12.5% of the light.
I suspect the accuracy of this conventions wavers a bit for “high-quality” $2 filters from eBay. 🙂
Anyway, I had some quiet time between coats of stain for my drawer handles this weekend, so I thought I’d meander out to the canyon and try out my ND8.
Bear in mind that I didn’t spend much time worrying about composition and the like. My main goal was just to see the differences between different shutter speeds. The thumbnails are the fast shutter speeds where the water is “frozen”. The large images are the slow shutter speeds where water becomes “silky”.