How to Focus Merge with Affinity Photo

James Paterson discovers how to use Affinity Photo’s focus stacking command for detail-rich macro shots

When shooting close-up macro subjects the depth of field (DOF) will be very shallow, and the plane of sharpness may only stretch a few millimetres across the subject, even when using narrower apertures. So it can be a struggle to record a sharp close-up from front-to-back. If you need total sharpness, then try focus stacking. This involves taking a series of shots using a tripod-mounted camera, adjusting the focus ring after each frame so that a different part of the scene is in focus.

Once done, the sharp parts can be merged into one super-detailed macro photo. Affinity Photo offers a powerful focus stacking tool called Focus Merge. Not only is it easy to use, it also produces excellent results most of the time. However, no focus-stacking software is perfect so – depending on the intricacy of the image – you might see messy blurred areas once the merge is complete.

If this occurs, fixing the problem involves looking back through each image that makes up the composite and tweaking the blend so that a sharper area is targeted instead. In this project we’ll explain how it’s done.

Select your image set

Initiating a focus merge in Affinity Photo is very easy. Simply open Affinity then go to File>new Focus Merge. Click Add in the dialog box and then navigate to your set of focus-stacked photos. Click-drag over the files to highlight them all, then hit Open to bring them into the New Merge.

Find sharper details

Click the Source Preview icon at the bottom left of the Sources panel to toggle it on. Now the view changes to allow you to click on each individual image that makes up the merge. Click through to determine if a sharper area exists than the one on the merged image. Here the bottom image offers a slightly sharper edge to the plant.

Clone the edges

Highlight the photograph in the Sources panel that contains the sharper area, then click the Source Preview icon again to return to the merged view. Next, grab the Clone tool and set Opacity to 100, then paint over the blurry area to fix it by cloning from the other image in the Sources panel.

Start the merge

Once you’ve chosen your images, hit Merge – this may take a few moments. First the images are aligned to correct for changes in subject size between each focus shift. Next a depth map is created to seek out the sharp parts in each frame, Finally, the sharp parts are merged together into one image.

Sharpen the details

Go to the Layers panel (View>studio>layers), then hit Cmd/ctrl+j to duplicate the bottom layer. Go to Filter>sharpen>high Pass. Set the Radius to about 2.5px, then go to the Layers panel and set the blend mode to Overlay. Make any other changes to finish off the image.

Check for issues

Once the merge is complete you’ll see the Sources panel appear. You can use this to manually fix any blurry areas if the merge has been unsuccessful. Zoom in close to check for problems. In this case some of the details in the plant aren’t as sharp as they could be.