I recently had an opportunity to walk along the coastal trail and sandy coves at Asilomar State Beach in Pacific Grove, California. It was also an opportunity to try a technique I had recently read about for turning a series of hand-held short exposures into something resembling a long exposure, without even using a tripod.
Well, not quite the same as a genuine long exposure, but interesting. Probably worth playing with some more on scenes with moving clouds or slower-moving water.
Here’s how to do it:
- If possible, adjust the camera‘s focus manually and set the exposure to manual mode, so that exposure and focus will not shift or interfere with the rate of exposures while shooting. Use a shutter speed fast enough to ensure sharp hand-held exposures.
- For waves, which are moving fairly quickly, shoot a high-speed burst of at least 10 images over 2–3 seconds. For slower-moving subjects, a slower burst rate over a longer period would suffice.
- Import the images to Lightroom or a similar application, process one of the images as desired, then synchronize those settings across the series of images to ensure consistent exposures. It’s the highlights that will produce the appearance of motion-blur, so you may want to touch-up the highlights on the waves or clouds separately in each image to make them bright, while retaining a little detail. Don’t crop yet; you’ll need to do that later anyway.
- Select a series of about 10 consecutive images (if you’re shooting crashing waves, like the above examples, the first or last several in your burst of exposures may not have highlights where you want them).
- Open them as layers in Photoshop. (In Lightroom, select all the images to export, then use Photo>Open In…>Open as Layers in Photoshop. This will take several seconds to a minute.)
- Now in Photoshop, select all the layers you just imported, and auto-align them using Edit>Auto-Align Layers. Of the options available, “Auto” will probably work correctly, but you could also select “Collage” to make sure transformations are restricted to repositioning, scaling, and rotation (you don’t want any perspective shifting or warping in this step). Save the file (PSD format).
- With all the layers selected again, combine them into a Smart Object using Layers>Smart Objects>Convert to Smart Object. Then, with that Smart Object layer still selected, do Layers>Smart Objects>Stack Mode>Mean. Now you see the “long exposure” effect.
- Optional: If there is unintended movement and motion-blurring in some part of the image that you want to remain sharp, copy one of the image layers out of the Smart Object, paste it above the Smart Object, and mask it as needed to reveal the motion blur where you want it.
- Double-click on the Smart Object layer and it will open as a new Photoshop file in a new tab or window.
- Turn off layers as needed to browse through the stack and find one that is sharp in the area where you want to eliminate blur. Click on that layer in the layers panel to select it, then Select>All to select the entire picture area, and Edit>Copy.
- Return to the file with the Smart Object and Edit>Paste the copied image into a new layer.
- Go back to the window or tab showing the layers in the Smart Object and close it.
- Now check to see that the newly pasted image is properly aligned with the Smart Object layer: reduce its opacity to around 60%, zoom in to 200% or more on some relatively sharp detail (not part of the motion blur), and nudge the image as needed to align the pixels. Return the opacity to 100%.
- Add a mask and make it all black (to hide the layer). Then, using a feathered white brush, paint on the mask in the areas that need improved sharpness. This will reveal parts of the single frame that look better, above the blended stack of layers in the Smart Object.
- Now you can flatten the image if you want to save on file size. This would also be a good time to crop the image because the repositioning of layers during auto-aligning may result in edges that are a little unclean or partly transparent.
- Continue processing the image, if you like, with adjustment layers, Nik or other third-party filters, and other edits as needed. Save the file when you’re finished!