Search found 18144 matches

by rjlittlefield
Sun Apr 11, 2021 8:35 am
Forum: Equipment Discussions
Topic: How Stupid Can Someone be? How about you?
Replies: 17
Views: 232

Re: How Stupid Can Someone be? How about you?

recommends to get the PCR Covid test in a week after the 2nd shot and it should show positive. I suspect some scrambling in the communication. Everything I read says that Moderna is an mRNA vaccine. It stimulates antibody production so it will likely produce a positive antibody test, just like a pr...
by rjlittlefield
Fri Apr 09, 2021 11:23 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Photomicrography demonstration on Zoom, 13th April 2021
Replies: 2
Views: 132

Re: Photomicrography demonstration on Zoom, 13th April 2021

Sounds interesting!

I'm glad to see that this will be available later as a recording, for those of us who are in radically different time zones.

--Rik
by rjlittlefield
Thu Apr 08, 2021 8:59 am
Forum: Equipment Discussions
Topic: Zerene Stacker performance on ARM macs?
Replies: 3
Views: 66

Re: Zerene Stacker performance on ARM macs?

Rashkh, welcome to photomacrography.net. I'm the fellow who wrote Zerene Stacker, and I answer all the support requests that come in by email. Here is what I recently wrote to another fellow: >Any comments on the Apple M1 for this sort of work? Is it much faster? It's a great chip, but important to ...
by rjlittlefield
Wed Apr 07, 2021 7:50 pm
Forum: Equipment Discussions
Topic: A7r4 pixel shift. Rather a resolution eye-opener
Replies: 17
Views: 319

Re: A7r4 pixel shift. Rather a resolution eye-opener

Here is an article on the topic by Jim Kasson. https://blog.kasson.com/the-last-word/does-pixel-shift-increase-resolution/ Unfortunately the body of that article has one significant flaw, and the subsequent discussion in comments is beyond my patience to try untangling. As I read it, the analysis s...
by rjlittlefield
Wed Apr 07, 2021 4:46 pm
Forum: Beginners Macro
Topic: Abbreviations for equipment and technicues
Replies: 8
Views: 127

Re: Abbreviations for eqiuppment and technicues

Rik, now that you mention it. I have the impression that Google lost track of a lot of the information on this site a while ago, maybe when the forum software was updated? There's been several times that I've tried to search for things that I know exists on this forum, but failed to find them using...
by rjlittlefield
Wed Apr 07, 2021 11:30 am
Forum: Beginners Macro
Topic: Abbreviations for equipment and technicues
Replies: 8
Views: 127

Re: Abbreviations for eqiuppment and technicues

Is there any abbreviation table or rules for describing the shooting technique? How can I correctly describe my photo in the gallery? There is no table. The main "rule" is only to try communicating accurately, completely, and concisely. Of course those three things conflict with each other, so some...
by rjlittlefield
Wed Apr 07, 2021 10:14 am
Forum: Photography Through the Microscope
Topic: Conjugating Mougeotia viridis - filamentous algae
Replies: 5
Views: 122

Re: Conjugating Mougeotia viridis - filamentous algae

Very nicely found, photographed, and explained -- thanks!

--Rik
by rjlittlefield
Tue Apr 06, 2021 6:35 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Hairy areas Zerene stackig problem
Replies: 8
Views: 182

Re: Hairy areas Zerene stackig problem

Thank you for the new images. Yes, I agree it is the same effect -- alignment being messed up by changing pattern of illumination. Have you ever encountered such instability in lighting? Yes, it is a common problem. One of the examples in my "How To Use DMap" tutorial is a small moth, shot with Spee...
by rjlittlefield
Tue Apr 06, 2021 3:58 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Hairy areas Zerene stackig problem
Replies: 8
Views: 182

Re: Hairy areas Zerene stackig problem

Thank you for the sample images. In the Google Drive folder, I see files named 2A0A8279.tif through 2A0A8283.tif, which I will call 279 through 283. I wonder if these are the frames you intended to upload, because they do not show any of the eye in focus. However, they do have sharp detail in some o...
by rjlittlefield
Tue Apr 06, 2021 9:02 am
Forum: Equipment Discussions
Topic: Focus stacking by moving only the camera (not the lens)?
Replies: 12
Views: 359

Re: Focus stacking by moving only the camera (not the lens)?

have yet to think of a simple way to find the nodal point The "nodal point" that you're talking about is actually the center of the entrance pupil, the so-called "no-parallax point" for panorama stitching. This is also the viewpoint = center of projection for normal perspective. The best way I know...
by rjlittlefield
Mon Apr 05, 2021 10:24 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Hairy areas Zerene stackig problem
Replies: 8
Views: 182

Re: Hairy areas Zerene stackig problem

I checked the source images are fine, no distortion on the eyes. Thank you for the kind words. I am not on social media very much, so it's good to hear that I am well thought of. Now, about your stack... Because the source images are fine, and the pattern looks like it could be on a depth contour, ...
by rjlittlefield
Mon Apr 05, 2021 8:31 am
Forum: Equipment Discussions
Topic: Focus stacking by moving only the camera (not the lens)?
Replies: 12
Views: 359

Re: Focus stacking by moving only the camera (not the lens)?

or is this a thing? Can someone point me at a doc or discussion? It's definitely a thing. See discussion at https://zerenesystems.com/cms/stacker/docs/troubleshooting/ringversusrail . The key point is that focusing by moving only the camera guarantees that there is no change of viewpoint (center of...
by rjlittlefield
Mon Apr 05, 2021 8:17 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Hairy areas Zerene stackig problem
Replies: 8
Views: 182

Re: Hairy areas Zerene stackig problem

For Zerene Stacker, a good place to start is with documentation on the main Tutorials index page, at https://zerenesystems.com/cms/stacker/docs/tutorials/tutorialsindex . I always recommend to study at least the first 7 bullet points, down to and including "Tips for Retouching", including the two vi...
by rjlittlefield
Sat Apr 03, 2021 9:42 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Purslane (Portulaca oleracea) seeds
Replies: 19
Views: 1386

Re: Purslane (Portulaca oleracea) seeds

If you want I can send you some seeds, if you give me your postal address. PM sent. Could it be very diffuse light allowing the interference to show through a thin top layer? I get the same thing with black beetles. If you diffuse the light enough (a lot - beyond ridiculous) then sub-surface patter...
by rjlittlefield
Fri Apr 02, 2021 10:39 pm
Forum: Beginners Macro
Topic: meta equipment choices in 2021
Replies: 19
Views: 436

Re: meta equipment choices in 2021

The equations help a lot in understanding this - I was reading about nyquist sampling last night but didn't know where to go from there I should have linked to my source: https://www.photomacrography.net/forum/viewtopic.php?p=124831#124831 . But of course there is more background. The formulas that...