- Ed Dozier
How to Perform Helicon Focus Image Retouching
Not every focus stack goes smoothly. Reality often gets in the way, with things like moving subjects and wind. Helicon Focus has an advanced feature to help you save otherwise ruined focus stacks.
What follows is a scenario where I took a 20-shot focus stack, using a Nikon Z9 with its “focus shift shooting” feature. Despite what people typically assume, focus stacks are just as useful for large subjects as they are for macro shots of tiny things like bugs. I took a stack of shots of a bird using my 500mm lens, where I wanted to get a thicker depth of focus, while using a wider aperture that gives the best resolution. If I had significantly stopped the lens aperture down, then diffraction would have ruined the resolution.
It should get mentioned that landscape photographers often run into the problem of needing a deep depth of field, but stopping down their lens will ruin the resolution. Focus stacks can solve this problem, although they often run the risk of having the wind move some leaves or branches in one or more shots of the focus stack.
Another reason you might want to bother with a focus stack is to get a couple of subjects into focus that aren’t positioned at the same focus plane. You can get a shot of each subject separately in focus, while trying to keep your camera still. The risk of unwanted subject motion is high, though.
Extended depth-of-focus shot
The shot above shows a bird with a larger depth of focus than what should be possible with the selected lens aperture. This is the result of a focus stack, even though there were a few problems getting here.
First shot of a stack of 20 images
You begin by using the Helicon Focus “Render” step, after first loading all of the images in the focus stack. Notice how a plant behind the bird’s tail is pretty out of focus, and then compare it to the cropped shot at the top of the article. You can see that I got a much deeper depth of focus by doing the focus stacking.
Note in the screen shot above how the stacked image on the right has the bird’s head ruined. The bird moved while shooting the stack of shots, leaving a bunch of ghosts. The left-hand side of the screen shot shows the last photo in the stack, with the plant behind the bird being in focus and the bird totally out of focus.
Select the ‘master’ shot to use for fixing the ghosts
I selected the photo that would be used as the ‘master’ to clone its parts in place of the right-hand ghosted shot. This is the photo that has the bird’s beak in best focus.
Select the ‘Copy’ option
I next clicked on the “Copy parts from source image” option. There are several options that appear at the bottom of the screen to be used while doing the ‘copy’ action. The main thing I used was to set the diameter of the brush to use.
Move the mouse over the part of the image to repair, as shown by the white circle in both images. Just hold down the left mouse button, and ‘paint’ over the defective parts of the stacked image. The master image portion under the circle will replace the ghosts in the stacked image.
If the copying operation isn’t looking successful, you can click the “Undo” icon to get rid of the repair work and try again (the “X” icon). There’s a “clone” option next to the “copy” option that you could try, instead.
The right-hand “?” icon will take you to an online help link that Helicon Focus has, to read more about using the program and its features.
The repaired stack
As shown above, the copying operation successfully got rid of the ghosting in the stacked shot. You can also see how the stacked shot has a deeper depth of focus that the un-stacked photo on the left.
Save your results
Once the retouching operations are done, you can then click the “Save” button in the “Saving” tab to finish saving the results. The saved photo can then be edited in other programs.
The image repair features in Helicon Focus can really save the day in an otherwise ruined image stack. You can’t always re-take the shots in an image stack, particularly when you don’t even know your subject moved until you’re back home processing the photos.
Helicon Focus is a more useful program than many people realize. There are a lot more focus stack opportunities than just insect close-ups.