Bowen park waterfalls and a neutral density filter

Bowen Park Waterfalls, Nanaimo

A neutral density filter is a grey filter, completely neutral in colour, which attaches to the front of your camera lens.  Its sole purpose is to allow you to use slower shutter speeds than what you would otherwise be able to.  You would not make use of one normally, as shutter speeds are often slow enough as it is.  Most people don't have one, or may even not know about their existence.

The top image was taken early in the morning without an ND filter.  The exposure time was 0.3 seconds.  This is slow enough to allow some blurring of the water's movements.  It produces a pleasant effect.  The bottom photograph was shot using a neutral density filter; the aperture and focus points are exactly the same.  The shutter speed is significantly slower though, being a full 20 seconds.

The difference is subtle, although I prefer the longer shutter speed over the shorter one.  I love how the rocks and moss in the stream stand out from the blurred water.

I have a confession.  The camera I used was a 1-inch sensor bridge camera; a Panasonic FZ2500 camera which comes equipped with a virtual neutral density filter.  A small switch on the side of the camera reduces the amount of light hitting the sensor, allowing you to shoot slower shutter speeds.  The switch was set to the 1/64 value - a 6 stop reduction in light.  If you take the 20 second exposure from the bottom image and divide it by the 0.3 second exposure from the top, you get 66.7 - close enough to the 64 times light reduction.

I have a variable neutral density filter which I use on my DSLR lenses.  It does the same thing, although it has the disadvantage of putting extra glass between my subject and the sensor plus being an extra thing to buy and carry to boot.  I have to admit to liking the sliding switch feature on the all-in-one camera though.