One of the bugaboos (sorry for the pun) of macro photography at high magnifications is ghosting—where foreground objects get out of focus as you move focus further away. These create halos around objects, and reduce the contrast of the result.
Turns out there is a technique for dealing with this, called slabbing. If you have 100 images, you might do ‘slabs’ of 10 at a time, and then combine the slabs.
But there are some tricks to doing it right. I had tried slabbing manually, and saw exactly zero difference in my result. One needs to overlap by a few images, for example. So you might do images 1-10 in the first slab, then 8-17 in the second slab, 15-24, and so on. The above image was done with slabbing, and a repeat of an early effort in Helicon software. A different bit of software, called Zerene, is another heavy hitter in the field of Focus Stacking, and has a built-in slabbing tool. (sounds vaguely odd, doesn’t it?)
This effort was done in Zerene, using exact the 10-images-per-slab method as outlined above. I had to do some retouching, as with the Helicon tool, but Zerene implements retouching in a better way.
Without going too far into it, you put one of the input slabs on the left side, and then use your mouse to pick up specific areas that might have gotten munged in the stacking process. This is great for cleaning up missing pieces and artifacts. It takes about 1-2 hours to do the whole process, from loading the stack to finishing up the retouching.
So not for the timid, lazy, etc. :)
I tuned up the image in Photoshop - a bit of sharpening, Curves, some white balance adjustment, and a bit of added saturation. It looks quite natural, so I am happier with this result than with the first try. Go, bugs!
1) Subject : Random bug in random weed
2) Camera : Sony a7R IV
3) Lens : Tube lens is Raynox 150
4) Other : Thorlabs parts for tubing and adapters.
5) M/Obj : Mitutoyo M Plan 5X
6) Magnification: ~5x
7) Lens Settings: ISO100, 0.5 sec
8) Stack # 88 shots
9) Lighting : LED desk light
10) NOTES : 10-image slabs overlapping by 3 in Zerene, retouched in Zerene, color balance, sharpening, curves, saturation in Photoshop.