Focus stacking
Increase the depth of field in images without resorting to a tiny aperture
Combine several images for an improved focus field in Photoshop Elements
SKILL LEVEL
Take things further
IT WILL TAKE
Up to several hours
YOU’ll NEED A camera, Photoshop
Elements 9 or later
Focus stacking is the art of taking the sharply focused areas of several images and blending them into a single picture. It’s of most use in macro photography, since depth of field decreases with focus distance, and taking photos at tiny aperture sizes to increase it means longer exposure times, the use of artificial lights and a risk of soft images thanks to diffraction as light rays bend at the edges of the diaphragm, spreading across multiple photosites on the sensor.
Lenses are often at their best with their apertures a few stops down from wide open, often around f/8, so stacking allows you to use them at their sharpest and tweak the depth of field in postprocessing. Users of full Photoshop can automate this technique, with the app automatically aligning and merging layers. There’s no such functionality in Elements, unfortunately, so everything has to be done by hand. We won't be covering alignment here, but it’s useful, because changing the focal point can make elements of the image appear to move in relation to one another. This can, however, be worked around.
Stacking allows you to use images at their sharpest and tweak the depth of field in post-processing
Setting up your camera in a fixed position, manually focussing the lens using live view and taking the required number of exposures can take time.
We did this using Expert mode in Photoshop Elements 12, a version of which is available on the Mac App Store, but the important tools were introduced in version 9. Ian Evenden