Water with Time Exposures
Water moves, and as far as photography goes, you can freeze it or let it run.
This tiny waterfall on Boise Creek is a favorite spot of mine. It’s easily accessibly, just park at the turn-off on Mud Mountain Rd near route 410, and hike a few hundred yards. Normally, the water is just trickling over that log on the left, but today it was flowing very strongly. The rivers and streams are down from their flood stages, but still quite high.
This is a four-second exposure, made with a neutral density filter that adds 8 stops to an exposure. I shot this at f/11, ISO 50, 240 seconds; without the filter, I could have shot it at f/8, ISO 50, 1/100th second. And in fact I did; it has a very different look and feel:
I prefer the time exposure, but the normal (short) exposure looks good, too. It is much more complex, while the time exposure is serene and quiet.
The neutral density filter is the ticket to this kind of photography, and of course you will need a steady tripod as well to take long exposures. A delay timer is also a good idea, but nearly any modern camera comes with that feature. A delay allows any vibration from pressing the shutter button to damp out.
The eight-stop difference is a big change; you can also get neutral density filters with fewer or more stops of density. A longer exposure would be even smoother; a shorter exposure, say ¼ to 1 second, would leave the water a little rough, and that texture can also be interesting. There’s no one right way to shoot extended exposures; if you get one neutral density filter, you will probably wind up with a handful of them.
I always buy my filters to fit my widest lens; I can then buy cheap adapters (step-up filter rings) to allow me to mount the larger filter on smaller lenses.