Capturing water in motion - River at Dusk

Just in case anyone out there didn't notice yet... I'm obsessed with photos that include moving water. Time to share some observations - of course it always depends on what you want to show and which mood the photo should transport. Since shooting water ususally means tripod anyway there's no problem to simply try different exposure times once you've set up the camera and picked a framing.

This photo was made yesterday evening at the river Alz. The sky through the trees had a warm orange glow because of the setting sun and an approaching thunderstorm. I cropped away a portion white sky in the top left corner which is why it has this "odd" aspect ratio. :-)


Alz River at Dusk (FinePix S5Pro, 28s @ ISO 100; f/16, 14 mm DX)

At 28 seconds, it's at the limit of what the automatic exposure programs - I'm using aperture priority most of the time - can do (the limit is 30s). But if you want a river to be smooth like this with really washed out water around rocks or cataracts, you need looooooooooong exposure times. I always try to be above 10 seconds for this type of photo.

Sidenote - this is one of the major drawbacks of the Fuji S5pro for me: it has no darkframe subtraction and I'm seeing a lot of hot pixels in 30s exposures (of course, I could do it manually with the aid of a tool like Blackframe NR but thats a separate post processing step and I try to stay in Lightroom only whenever it is possible).

For close ups of the movement of water in a river that should show some of the dynamic, exposures in the range of 1/2 to 3 seconds are good. A wave in a river (where it flows over an underwater rock or something) will still have enough shape and structure that way to transport the sensation of water rushing by.

Waterfalls are pretty easy - at least if they deserve the name and are not ephemeral thin falls that only show after rain. With the help of a polarizer and some stopping down of the lens its possible to get a soft blur of water falling down (if its falling fast enough) at exposure times from 1/10s on while retaining enough structure - with a stabilized lens or camera, short focal lengths and a steady hand its even possible to get these shots handhold (links to my Panoramio photo of a handheld waterfall). The other approach for waterfalls would be really long exposures (15+ seconds) - again, it depends on what atmosphere you want to transport.

One exception are really big waterfalls (I'm talking about Niagara, Iguacu and the like here): in my humble opinion, photos of big waterfalls look better with short exposure times (1/250s or shorter) to freeze the motion of the water, and it should really be tack sharp then - this transports the sheer size of the fall and the masses of water much better than a blurred and soft long exposure.

I finds brooks and little creeks most difficult: when there's not much water and/or not much movement, the surface won't have enough random movement to really blur things -OR- it will be too small, and with a lot of blur the water might become so transparent (especially with a polarizer) that it becomes hard to recognize in the photo, but to make a photo with blurred water really work the water itself must be clearly recognizable.

General notes - a circular polarizer is your best friend once more - it will reduce glare and reflections and allow longer exposure times through that (I've written about it here). In addition to that, a neutral density filter is a good addition especially during the daytime - but depending on the camera and filter it might introduce color shifts.

And one thing that always seems to work miracles on photos with moving water is the "Clarity" control of Lightroom/ACR. Depending on the scene and desired result, you might want to try a strong boost or a negative clarity - Lightroom's graduated filters (and paintbrush too) are really nice helpers for that. I've shown an example here (yes, not the best, I admit it).

The best thing about long time water exposures is actually doing it. Its such a relaxed activity. Slow pace. While you wait for the 30s exposure to finish you can look around and identify other potential subjects for a photo, prepare a different lens or filter - or just sip on your beer (if you brought one, which is what Boyd Norton recommends anyway in his book). :-)