Silky water and cloud movement

Equipment Needed

Camera
Tripod
Remote Shutter Release
ND Filters - a range of both solid and graduated

Introduction

Where we meet a scene with moving water or clouds, it’s possible to use a long exposure to capture that motion in a still image. Depending on how much available light is in the scene, we can use an ND (“neutral density”) filter of varying strengths to limit the amount of that light entering the camera for a given aperture, resulting in slower shutter speeds than would normally be possible.

This technique could apply to movement above an iconic landmark, a natural landscape or a cityscape during golden hour.


For this tutorial, we’re using an example captured just after sunrise.

01

SETTING UP THE SHOT

First, we’ll compose the scene with our subject on the 1/3 line, aiming for the motion of the clouds to give us a leading line towards it.


If necessary, we’ll use a graduated ND filter to balance the light across the scene – darkening the top section of the frame by 2-3 stops (in this case, it’s a 3 stop soft graduated filter in use – meaning the top of the filter is 3 stops darker than the bottom). Without this filter, we’ll struggle to expose the entire image correctly.


Once we’re satisfied with the composition and exposure across the scene (checking for any over/under exposed areas), we’ll take a test shot at our desired aperture. This gives us our base exposure.


Next, we’ll take that base exposure (in this case, 2 seconds) and work out how long we want our final exposure to be. Given how slowly the clouds were moving, I wanted a 2-minute exposure (120 seconds), so we divide our target exposure by our base exposure to give the amount of extra Neutral Density we need to apply. In this case, 120/2 = 60, or roughly 6 stops. ND filters come in varying strengths and are labelled as either their density (0.6, 0.9, 1.2), stops of light (2, 3, 4) or ND value (4, 8, 16). The closest filter we can use in this case is a 6-stop filter, labelled as “ND64”, “6 stops” or “1.8”.


Add the ND filter in the slot closest to your lens, with the graduated ND filter we used before in the next slot, nearer to the subject.

02

CAPTURING AND IMPROVING THE SHOT

Ideally, we’ll be using either a remote shutter release (either cable, or wireless) or the built-in vibration delay on the camera itself to avoid any shake when we click the shutter button to initiate the shot.


Where possible, the use of an electronic shutter will also help prevent any “mirror shake” from the mechanical movements inside a DSLR system.


Once captured, try experimenting with different exposure times – if the water is too “milky”, try a shorter exposure. If the clouds aren’t moving enough, try a longer shutter – in both cases, adjusting the ND filter in use to accommodate your new settings.

03
POST-PROCESSING

No filter is going to be 100% perfect at controlling highlights or shadows across a diverse scene. With this in mind, using software such as Capture One Pro to maximise the camera’s dynamic range by recovering highlights and shadows can help to bring every detail in the scene back to how you remembered them.


To add a “pop”, a small amount of natural “clarity” (up to 20 on the slider scale) helps with definition, and use the “levels” tool to ensure your shadows are deep, rich, dark tones while highlights are bright enough to stand out when printed against a white mount/background.

Choosing the right filters to get the best exposure

Light Trails