Long exposure settings for water

There's more than one long exposure look for water. Half a second and thirty seconds can turn the same scene into two completely different shots.

16 August 20269 minute read

A small water cascade on Escley brook in Hereford. Taken with my new 105mm F2.8 lens.

Before you pick a shutter speed, decide what you want the water to look like. Everything below works back from that, and the answer changes with the water, the light and the day. If you start from "I'm doing a long exposure" and find out afterwards what it did to the river, you tend to end up with the same shot of every bit of water you visit.

Long exposure water settings: quick reference

Shutter speed	Typical look
1/15s to 1/4s	Movement and texture still visible
1/2s to 2s	Smooth water with direction and structure
5s to 30s	Much of the surface texture disappears
2 minutes and beyond	Water becomes highly abstract and smooth

Pick the shutter speed from two things, how fast the water in front of you is moving and which of those four looks you want, rather than from whichever ND filter happens to be in the bag. It sounds obvious, but the bag wins more often than any of us would like to admit, and that's how so many long exposures end up thirty seconds long for no particular reason.

The main shutter speed ranges

1/15s to 1/4s: movement without losing the water

Waves, strands and texture all survive here, and the water still looks like water doing something. It's the range to go for when the movement itself is the subject, and it gets overlooked a lot, as a quarter of a second doesn't feel much like a long exposure. Small streams and rocky shorelines suit it, and so does pretty much any woodland beck.

A wave breaking over a rusted piece of old crane lying in the sea between rocks, the spray blurred into white streaks. — 1/10s at f/7.1 and ISO 100 on a Canon EOS 1000D, as a wave swamps part of an old crane lying in the sea. At the short end you keep the shape of the spray, with just enough blur to show it moving (and you don't need fancy kit to do it).

1/2s to 2s: the classic long exposure look

This is the classic look. The water smooths out but keeps its direction, retreating waves turn into streaks that still point somewhere, and waterfalls keep enough structure to look like falling water rather than something poured down a rock. It's the most useful band in the table and often the cheapest, as in anything other than bright sun you won't need a strong filter. A polariser will often get you there on its own.

A small woodland stream running over wet rocks into a still pool, the falling water smoothed into a soft blur. — One second on a small stream. The water has gone smooth, and you can still follow exactly where it runs over the rocks.

5s to 30s: most texture disappears

The sea flattens and the cloud starts to move, so you're now photographing two moving things instead of one. Busy water turns into a simple area of tone. That's a great way to cut a cluttered coastline back to the rock shapes you came for, but not so good when the water itself was the interesting bit. This is also where the stronger ND filters earn their place in daylight.

A clifftop path on Portland with pale rocks and grass in the foreground, and a glassy smooth sea running along Chesil Bank towards a town in the distance. — 30s at f/7.1 and ISO 100, looking along Chesil Bank from Portland. The sea has gone completely flat, and the rocks in the foreground give the shot something solid to hold on to.

Two minutes and beyond: abstraction

Past a couple of minutes nothing keeps its original form. Water goes glassy, cloud pulls into streaks, and the shot becomes more of a graphic than a record of movement. It can look beautiful, but it's a very strong look and it'll fight anything else in the shot that's trying to get attention, so save it for simple scenes.

Choose the shutter from the water

A fast stream can look completely smooth after half a second, whereas slow sea movement on a still evening might need thirty times that to do anything at all. So watch the water for a minute before you touch the camera, decide what you want it to do, then work out which filter gets you there. If you build every exposure around the filter you own, every bit of water starts to look the same, and you end up with a folder of very tidy shots that all look like each other.

A tall, thin waterfall dropping from a rock overhang into a wooded gorge at dusk, the water smoothed into a white ribbon. — 1/2s at f/10 and ISO 500 on South Falls at dusk. Fast falling water like this goes smooth very quickly, so half a second is plenty and there's no need to reach for thirty.

Filters

Circular polariser

A polariser cuts the glare off wet rock and water, and it's the only filter here doing something you can't do afterwards on a computer, so it goes in the front of the bag. It also costs you light, which on an overcast day is often enough to drop the shutter speed into the half second range. Two jobs from one bit of glass!

6-stop ND

The one to get if you're only getting one. In overcast daylight, six stops takes a normal handheld shutter speed into the low single digit seconds, which lands you in the classic band without doing sums in the wind. It's not exciting, but it's the filter that gets used.

10-stop ND

For much longer daylight exposures, and very useful when that's what you want. It's a lot less useful once it starts going on every time you see water (a real risk once you've paid for one). Use it to reach a shutter speed you've chosen.

Variable ND

Convenient, and the one filter in this list where quality really shows. Cheap ones give uneven darkening across the shot or a dark X through the middle, worst on wide lenses at the strong end of the range, and you won't always spot it on the back of the camera. If you're going to buy one, this is the filter to spend a bit more on.

A simple workflow

Compose first, before the strong filter goes on. A ten stop can turn the viewfinder black.
Set focus, then switch to manual, so the camera doesn't start hunting through dark glass.
Meter without the filter and note the shutter speed. Then add the filter and adjust by the right number of stops. Six stops means six doublings, so 1/30 becomes two seconds.
Keep the camera still. A remote, a cable release or a short self-timer, whichever you have.
Check the result, not just the maths. The calculated exposure can be spot on and still give you the wrong look, so look at the water and decide whether to go shorter or longer.

Turn stabilisation off on a tripod

Some systems spot the tripod and deal with it themselves. Others start hunting for movement that isn't there and end up adding some, and you usually find out at home on a file you can't reshoot. Check which one you've got, as this one setting is behind a lot of soft tripod shots that get blamed on the tripod.

Common problems

Colour cast

Strong ND filters shift the colour, usually towards blue or magenta, and the stronger the filter the more obvious it gets. Shoot raw and correct it afterwards. It's a two slider job, so don't let it put you off using the filter the shot needs.

Everything is moving

If the water, the cloud, the grass and the trees are all blurred, there's nothing sharp to hold the shot together and it all ends up looking a bit soupy. Keep something solid in there, like a rock, a post or a building, anything that stayed put for the whole thirty seconds. Composition beyond the rule of thirds makes the same point about giving a shot something to anchor it.

Stopping down too far

Using f/22 just to get a longer exposure costs you sharpness, as diffraction softens the whole shot. The loss isn't dramatic, but you can't get it back either. A filter is the better answer, and failing that, a lower ISO and a polariser will usually get you further than the last two stops of aperture.

Athabasca Falls in Jasper National Park, the water turned to a smooth white blur between a dark foreground rock and pine trees below a snowy mountain. — Thirty seconds at f/22 and ISO 200 on Athabasca Falls. At f/22 you give away a bit of sharpness to diffraction, and around three stops of ND would get you the same thirty seconds at f/8, where most lenses are sharper.

Ignoring the tide

Less technical than everything above and a lot more important. If you're on rocks or a shoreline, keep track of what the water is doing, as it's easy to forget whilst your camera takes thirty seconds over every shot. Check the tide times before you go, know your way back off the rocks, and keep well back from big waves. The tide comes in behind you, and wet socks are the best case!

Start shorter than you think

If you normally reach straight for thirty seconds, try one second instead. Then half, then a quarter, and look at all three side by side, as the one that still looks like moving water is often the one you end up preferring. The Long Exposure Mission on Kōlab is handy for this too. The exposure time sits right next to each shot whenever someone has Shot Recipe on, and seeing the number next to the result beats being told to use a long shutter speed.

Shoot itLandscape

Long Exposure

Water, cloud, traffic, stars. Anything where time is part of the shot.

Woodland streams in flat light are the easiest place to practise the short end of the range, and they're half of what autumn is good for. And if you want light where the filters can stay in the bag, try blue hour.