Additional Considerations:
Investment
Macro lenses can be had on the cheap, so to speak, because in
macro photography (and absolutely in focus stacking) only manual
focusing is used. Auto focus is not needed or desired. Because
most photographers today think only in terms of auto-focus lenses,
a good Nikon 105mm f/2.8 lens can be found on Ebay for between
$200-$300. Of course you can pay a lot more, but you can do fine
macros with the Nikon 105mm macro lens or the Canon equivalent.
Playing With Stacks
Back on the computer, after a day’s shoot, you process a stack in
Photoshop and look at the results. Some stacks work and some
have too many artifacts, motion that you didn’t see at the time,
areas that Photoshop could not distinguish properly, etc.
Some stacks are simply beyond use or repair but most are not, so
don’t just give up on a stack because at first glance it has problems.
Try to see what is causing the problem. Here are some things you
should check out before giving up on a stack.
Inherently Flawed
Don’t forget that unless you are on a focus rack and taking a huge
number of photos under essentially laboratory conditions that photo
stacking, by definition, is flawed. Focusing using a short-stack
means you are sampling the focus here and there rather than
seamlessly photographing and merging the entire frame. By design
you are leaving out many areas of the photo which are not treated
as a focus point. This is a choice we make when we stack photos.
Focus stacking is by definition impressionistic.
An Art, Not a Science
There will be areas that are (how ever so slightly) out of focus. The
art of focus stacking is to make these areas as unobtrusive as
possible, selecting what you feel are the key areas in the photo that
tell the story as you see it, areas that you want to be in sharp focus.
Focus stacking, at least in my experience, is more of an art rather
than a science. Slavishly using a focus rack to obtain perfect focus
through a stack of a hundred or so photos simply is not interesting
to me and way too time consuming. I am happy to look at the deep