Combine images to form the best blur

Set up for a long exposure

Set up on a tripod and compose the scene, then focus and switch to manual focus to lock it in place. Fit the ND filter then set Manual exposure mode, use an aperture f/16 and Auto ISO and set shutter speed to around 20 secs, or whatever length results in ISO100. Take your first shot.

Go faster

Increase shutter speed to 10 secs, then 5, 2 and 1 sec, and whatever else you like. The faster shutter needs a progressively higher ISO (here for one second it’s ISO1800), which means more image noise, but as we’re likely to use only the blurred water from the faster frames, loss of detail is not a concern.

Reveal the blur

Grab the Brush tool, set the colour to white and paint to reveal the parts of the layer that you want visible – here it is the streaks of blur in the waterfall. We’ve also blended a third, darker frame in this project to introduce the brighter details and sky in the distance and complete the image.

Tone in Photoshop

Highlight your frames in Adobe Bridge, right-click and ‘Open in Camera Raw’. Highlight all the frames and adjust the tones to boost contrast and colour so that they match. Next, highlight the image with the higher ISO, go to the Detail panel and increase Noise Reduction to tone it down.

Final toning

When you’re happy with the blend, hit Cmd/ctrl+shift+alt+e to merge a copy of the layers, then go to Filter > Camera Raw Filter. Use the local adjustment tools to enhance the blur. Hit K and paint over the blurred water streaks, then increase Clarity and Exposure to lift them.

Load into layers

Hit OK to go back to Adobe Bridge, then (with the images still highlighted) go to Tools > Photoshop > Load Files into Layers. Once loaded, drag the faster frame to the top of the stack then hold Alt and click the Add Layer Mask icon to add a full mask that hides the layer.