Nice pictures! I'm curious what's causing the fine-grain speckle noise, particularly evident in your second picture. Are you having to run the camera at high ISO to handle low light? For these static subjects, can you reduce the ISO and make the exposure longer?
Reducing the noise would be good for both appearance and file size. IE tells me the second picture is 395237 bytes, the first one only 296426. I'm pretty sure the first one could be cut back to forum limit of 200K bytes without losing much quality, but I'm not sure what would happen to the second one. Sometimes higher compression is not friendly to images with lots of noise.
well, I always leave ISO at 100. The second pic is a stack of two pics, done with CombineZ. The stacked image had more details in focus, but turned out to be a lot more noisy than the originals. This time I chose to show this one all the same, because I sort of liked the painting- like, almost artistic aspect about it, but that certainly is a matter of taste.
Hhmm... Seems like stacking should not add so much noise. I suspect the stacking process is oversharpening very fine detail, which is mostly noise in this case. What macro did you use? What parameter settings? Did the original images look about as smooth as your first pic in this post?
I agree the speckle is attractive in this case. I just like to know where these effects come from -- how to get them when I want, and make them go away when I don't.
unfortunatly I deleted the original pics, I would have loved to show them. To be precise I used the "do average and filter" mode in CombineZ5.
Being not a native speaker, I'm not sure what you mean with macro.
Well the objective is a simple achromat (nothing to write home about) and the camera is a Coolpix 990. ISO 100, aperture around 3,5, exposure time 1/8 sec.
Maybe I did the unsharp masque a bit sloppy, I do have the suspicion that you have to be a lot more careful, when it comes to sharpening stacks.
"do average and filter" answered the question. At least in the English version of CombineZ (are there others?), the main menu of commands just to the right of "File" is titled "Macro". The individual commands like "Do Stack", "Do Average and Filter", and "Balance and Align" are called "macros". The term "macro" here has little to do with photography. It is a computer science term that means putting together smaller commands to form a larger one.
The standard "Do Average and Filter" macro (command, mode, whatever we call it) seems to be tuned for deep stacks, where random noise has become small because of so much averaging. With a shallow stack, it does tend to overemphasize noise. That could be what's happened here. Or maybe it was too much unsharp mask, as you suggest -- they are pretty similar.
The operation of CombineZ's "Do Average and Filter" macro is controlled by one parameter, buried inside the macro. In particular, the second command inside the standard macro is "Create a Highpass Filter (1000,200)". Changing that second number (200) gives more or less emphasis to noise. I think that smaller means sharper = more emphasis to noise, but I'm not sure offhand.
With such a shallow stack (2 frames), CombineZ's "Do Stack" or "Stack Only" macros would probably work well too, and they generally add less noise.
I cannot recommend Do Stack or Stack Only for use with deep microscopy stacks, though. They model the subject as an opaque surface that has detail at only one depth per pixel position.
Many microscopy subjects have detail at many depths, at overlapping pixel positions. With those, CombineZ's Do Stack and Stack Only will often produce undesirable "swirly" artifacts. Do Average and Filter does not have this problem. Helicon Focus uses a completely different algorithm that also handles this case very well.
Seems like stacking should not add so much noise. I suspect the stacking process is oversharpening very fine detail, which is mostly noise in this case. What macro did you use? What parameter settings? Did the original images look about as smooth as your first pic in this post?