Bruce Taylor wrote: ↑

Tue Mar 25, 2025 7:52 pm

Campanella.

--Rik

Nice colors!

I see forked stalks that do not contract, so these are not Vorticella. Maybe they can be Epistylis?

--Rik

This is very interesting! There is an obvious small scale hexagonal pattern visible in some of the cell walls that run perpendicular to the slide, front-to-back in this view. They are most obvious below/left of center, a little below the big holes. Does anybody know what this hexagonal structure is?...

First thing I noticed was that I could not get it aligned near good enough. I am curious: what do you mean by "aligned"? This latest image looks OK to me as far as the stacking goes. At first glance the image does appear to be streaked, but I'm pretty sure the apparent streaking is physically prese...

I’ve read a fair amount here about telecentric systems, however, which still confuse me conceptually. I don't think I can add much beyond what I've already written about telecentric systems. Be sure that you've read the three basic threads: https://www.photomacrography.net/forum/viewtopic.php?t=103...

I Know your Zs does a better job of stacking, but speed and the integration of HR seduced me. :) No worries -- I don't care how you get a good result, as long as you do get a good result. That penny date was way off. It's a red flag to get a better result from Photoshop/Lightroom than you get from ...

So these are stacks?

If so, they are badly aligned, especially the date on the penny.

How are you shooting and and processing them?

--Rik

Ah, okay, got it, that makes sense - two different approaches, two different interpretations for the scale! Just so. Every scale has an intended purpose; most scales can also be repurposed. But sometimes you need a different sort of scale. In the literature for view cameras, there is a standard pro...

At the time we were using JPS for static pairs, but there may be some useful information at viewtopic.php?t=16742 .

--Rik

For principal planes, study the diagram in the thread that you mention. Their locations can be determined from the measured focus points, focal length, and magnification. Smallish pupil diameters and locations can be measured accurately using the "shallow DOF macro" procedure described at https://ww...

Though the scales on the jumping spider looks very much like a modified hair, especially with the serrated edges. Yep. Quoting from page 71 of "Biology of Spiders" by Rainer F. Foelix, 2nd Edition, page 71, the caption of Fig. 61: (c) Scale hair from the jumping spider Salticus . The leaflike hair ...

But no matter what, the DOF scale on the lens is still correct even with smaller or larger sensors. Here's an illustration you may like better: https://janrik.net/MiscSubj/2025/topic_47027_DOFandSensorSize/DOF_scaleOnLensTake2.jpg With this labeling, I agree completely that it doesn't matter what s...

I would like to introduce here a couple of new terms that I think may help to communicate clearly. One new term is empty DOF . I think we are all comfortable with the term "empty magnification", which means to make an image larger but reveal no more detail. By analogy, "empty DOF" means something th...

To me the DOF-scale on the lens would apply regardless of the sensor size it's being used on, as it is "agnostic" to whatever it's projecting the image onto, it's only accounting for magnification and aperture (which is all it has to in order to show a good approximation for the resulting DOF). ......

So that formula should only be expected to give meaningful results when P is below or around 1? I don't think there's any general answer to that question. If your P=3.45 lens were stopped down a lot farther, then the lens element diameters would pose no difficulty. The problem is only that the comb...