Well, I am all grown up now and habituated to retouching just as I
had to learn to enjoy stacking the photos in the first place. Things
change and even I do
too, albeit probably more slowly than average. That being said,
let’s talk a bit about retouching stacked photos.
Some of the focus-stacking software is amazing at what it can do
considering there is no human making real-time on-the-spot
decisions when they are needed. I checked out (and purchased!)
various focus-stacking programs and finally settled on Zerene
Stacker as being IMO the best of the lot. There are many roads that
lead to Rome and we can’t easily walk them all to the end, so at
least for now I am walking with Zerene Stacker.
Since I am a systems programmer I guess I am allowed a
professional opinion and I must say that this is a wonderful piece of
programming that Zerene Stacker’s author Rik Littlefield has put
together. It is a brilliant program. And its retouching features are
almost ideal and this is what I will be looking at here in this post.
The problem inherent in focus stacking is that, because it is
essentially a sampling technique (like CDs, DVDs, etc.), by
definition sampling ‘samples” parts of the whole and leaves other
parts out. Where the samples come together there are always
holes or gaps and this naturally produces artifacts that may or may
not blend well in the final photo. While most artifacts may be lost to
even the vigilant eye there usually (or often) are stubborn artifacts
that detract from the finished photograph. And I don’t like em’.
The artifacts are not entirely random and can be grouped into
general types. Perhaps the most common type of artifact is what is
called a “halo,” an artifact which manifests when a sharply defined
edge of an object (like a leaf) is contrasted by the more distant
background bokeh behind it. Along the edge of the leaf a small dark
halo appears that catches our attention every time and can spoil
the photo.
Another common artifact occurs when one object in the detail
overlaps another but is at a distance above or below it. This is
really the same halo-problem discussed above but in a different
form. Trying to separate one overlapping detail from the other can
be too difficult for the program with the result that where the two
intersect are some out-of-focus blurs that are not welcome.