cube-tube, thanks for the closeups.
The whole frame images appear to have gotten shrunk by SmugMug. It let me download, but the images came down as 2048x1365.
Looking at your crops, the CA does not look excessive to me. If you need less false color than this, as shot, I expect you'll have to move up to an apochromat, typically the
Mitutoyo 10X NA 0.28 M Plan Apo. That's an expensive lens, but in good condition it's very sharp and has little or no false color. The working distance is also great, 33.5 mm. Green fringing on a brown subject can probably be fixed by a defringe filter in post-processing, but other people can advise you better than I can on that topic.
Your middle and bottom crops look good to me. They look soft from diffraction blur, but that can be helped a lot with some aggressive sharpening as discussed recently in apt403's thread at
http://www.photomacrography.net/forum/v ... 084#250084 . In Lightroom, I'd suggest something like Amount 100 and Radius 1.5, but just play with it to see what you like. Note that such hard sharpening will also bring up the noise levels, which is why it's important with deep stacks to shoot at the lowest possible ISO.
Back to the top crop, two issues do catch my attention.
First is that the rear claw looks quite murky, especially near its base. But that also looks like normal behavior, caused by the large amount of out-of-focus light contributed by foreground areas that are seen by the wide aperture of the NA 0.25 microscope objective. See
http://www.photomacrography.net/forum/v ... 042#135042 for some discussion and illustration of that issue. As mentioned by apt403, some of the detail in that region can probably be restored by filtering, but there are limits even to that approach. It may sound fatalistic, but my recommendation is to just get used to the idea that it's tough to see much detail through small gaps and bristle mats, especially when the detail that you're trying to see is dark and the foreground structures are light.
Second issue with the top crop is that the big foreground claw has a large featureless area on its upper left surface, around the area of that big bend. To go with that, there's a brighter band around the edge next to the dark background, extending down the claw as a narrower band. Given the rich texturing elsewhere on the claw, part of my head is screaming that that looks like a stacking problem. But on careful study, I suspect that the claw really is featureless in that area, and the bright band is just a reflection of some illumination coming in at an unexpected angle, something like a rim light component in what is otherwise frontal illumination.
--Rik