How To: Focus Stack in Landscape Photography
There are two basic scenarios when shooting landscapes that may benefit from focus stacking.
The first is when the subject is a close foreground object with an interesting background, and you want both these elements to be in sharp focus.
The second is when using a telephoto lens (which typically has a shallow depth of field) and the subject covers multiple distances that may need to be brought into sharp focus. This image of irises and buttercups around a pond is a good example of how focus stacking can create an image that is sharp from the foreground flowers to the background trees.
The foreground buttercups are in focus but the shallow depth of field of the lens renders the middle and backgrounds out of focus.
How to Focus Stack
Focus stacking combines a number of images taken at different focus distances through a scene. To acquire these images for processing the following steps are taken:
Place the camera on a sturdy tripod
Compose the shot.
Determine exposure for the scene and set the camera to manual mode to ensure that the exposure is constant for every image.
Aim the focus point at the nearest object you want in focus. Use the camera’s zoom (the plus button, not zoom on the lens) to preview the focus through Live View if available.
Take the first exposure.
Without moving the camera or adjusting any settings, move the focus point to an object mid-way in the image and refocus.
Take the second exposure.
Again, without changing anything, refocus on an object at the farthest point of the intended image.
Take the third exposure. To capture landscapes, three images are generally all that is necessary to create sharp focus stacking images, but it’s completely fine to take extra images to make sure that the entire scene is covered. A rule of thumb would be to add more images for longer focal lengths.
Some of the newer Nikon DSLRs and Mirrorless Cameras have a built in option to automate these steps, allowing the photographer to select the closest focus point, and then the number of images to be taken and the amount of focus shift between images. These can be then processed in Photoshop or other image editing software
A number of Nikon cameras are able to automatically acquire the images needed for focus stacking via the Focus Shift Shooting menu
Processing the Final Images
Processing the files to achieve the final image may seem like the most difficult part of creating a focus-stacked image, but it’s really very simple to do in Photoshop.
The auto-blend layers menu within Photoshop
Open Photoshop
Open each image on a separate layer.
From the Edit menu select Auto Align Layers and leave the option for Auto.
Click OK and wait for Photoshop to align the layers. There may be transparent areas generated during the alignment process but these will be dealt with later.
Once completed open the Edit menu and select Auto-Blend Layers.
Select the radio button for Stack Images and select the tick boxes for Seamless Tones and Colors. Optionally, select Content-Aware Fill Transparent Areas, which will fill any transparent areas generated by aligning images in step 4. (Be aware that this will increase processing time. Generally, I do not choose this option; rather, I just crop the image slightly later, if necessary.)
Click OK and wait for Photoshop to blend the layers.
Flatten the image by opening the Layer menu and selecting Flatten Image.
Crop the image as preferred to remove any transparent areas or unwanted edges.
A focus stacked image using 7 separate photographs combined together in Photoshop to create a single image with sharp focus throughout