Search found 17983 matches

by rjlittlefield
Mon Jan 18, 2021 12:43 pm
Forum: Photography Through the Microscope
Topic: ...two little babies on the way...
Replies: 3
Views: 65

Re: ...two little babies on the way...

Thanks for including the original. That matches pretty close to what I got by inverting the lightness channel in an Lab version of your post at top of thread. But it does not match exactly, so now I am curious. I notice that in your original, the eyes are very dark, almost black. With inverted lumin...
by rjlittlefield
Mon Jan 18, 2021 10:41 am
Forum: Photography Through the Microscope
Topic: ...two little babies on the way...
Replies: 3
Views: 65

Re: ...two little babies on the way...

Excellent -- and that is a very clever trick, to invert just the luminosity channel so as to convert brightfield to darkfield while preserving colors!

--Rik
by rjlittlefield
Sun Jan 17, 2021 10:45 am
Forum: Equipment Discussions
Topic: 50X objective recommendation
Replies: 29
Views: 902

Re: 50X objective recommendation

With regards to focus blocks, the well regarded Olympus BHMJ is actually quite expensive. Would something much cheaper (e.g. https://www.ebay.com/itm/Stereo-Microscope-Adjustment-Coaxial-Coarse-and-Fine-Focusing-Arm-E-Head-Holder/273448954661) be equally suitable/capable? Very interesting! Today's ...
by rjlittlefield
Thu Jan 14, 2021 12:12 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Looking for advice to improve sharpness
Replies: 7
Views: 268

Re: Looking for advice to improve sharpness

Viewing your image at full resolution (5496 x 3864), I see a lot of lateral chromatic aberration -- color fringes away from center on light vs dark transitions. That is a property of the objective. You can eliminate the obvious fringing with post-processing in Photoshop and similar tools, but fringi...
by rjlittlefield
Sun Jan 10, 2021 9:31 pm
Forum: General Discussion Forum and Community Announcements
Topic: Having trouble uploading avatar
Replies: 4
Views: 163

Re: Having trouble uploading avatar

In CS4, I believe it was File > "Save for Web & Devices", so directly under the File menu, not under Export.

--Rik
by rjlittlefield
Sun Jan 10, 2021 6:50 pm
Forum: General Discussion Forum and Community Announcements
Topic: Having trouble uploading avatar
Replies: 4
Views: 163

Re: Having trouble uploading avatar

What's making your files too large is metadata embedded in them. Get rid of that and there should be no trouble with size. In Photoshop, the simplest approach is to save the image using File > Export > Save for Web (Legacy). Using GIMP, follow the instructions at https://www.makeuseof.com/tag/3-ways...
by rjlittlefield
Sun Jan 10, 2021 11:38 am
Forum: Photography Through the Microscope
Topic: Sea Urchin Spines SEM
Replies: 7
Views: 347

Re: Sea Urchin Spines SEM

Thanks for the detail about preparation. About the colors, I have seen Pau's approach used a few times. Doing it fully automatically is indeed tricky because you have to match perspective -- not just viewing angle but also distance from center of perspective to the subject. This requires a careful m...
by rjlittlefield
Sat Jan 09, 2021 10:27 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Help with Zerene Stacker
Replies: 11
Views: 426

Re: Help with Zerene Stacker

Thank you for the additional information. These images look great. I like to hear your thoughts on the fuzziness around the hairy portion of the seed. Do you think if that can still be minimized further? If so, how? I assume that by "fuzziness" you refer to areas like I have marked here, where it se...
by rjlittlefield
Sat Jan 09, 2021 8:27 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Help with Zerene Stacker
Replies: 11
Views: 426

Re: Help with Zerene Stacker

Great!

Can we see the final image, please? I am very curious what this subject looks like (and what it is, for that matter).

Also it would be great to get some information about magnification, step size, number of frames, and so on.

--Rik
by rjlittlefield
Sat Jan 09, 2021 12:53 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Help with Zerene Stacker
Replies: 11
Views: 426

Re: Help with Zerene Stacker

I notice three things that seem relevant: 1. In the right-hand image, the front structure is very high contrast and is surrounded by a discolored edge. This suggests an extreme value of "brightness" adjustment, caused by having some source frames that are very different from other source frames. 2. ...
by rjlittlefield
Sat Jan 09, 2021 11:51 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: mountain swallowtail
Replies: 9
Views: 410

Re: mountain swallowtail

I have compared DMap interpolated with "Bicubic", "Lanczos2", "Lanczos4" and found no difference. But in general, DMap performance is much better than PMax, regardless of interpolation method. Does it depend on the blue scales or my setup? In general, DMap is better at handling simple geometries th...
by rjlittlefield
Fri Jan 08, 2021 5:55 pm
Forum: Equipment Discussions
Topic: Raynox dcr150 custom tube lens
Replies: 21
Views: 725

Re: Raynox dcr150 custom tube lens

I am curious about the motivation for custom design & build.

Why not just assemble a flocked tube from standard parts, for example as in viewtopic.php?t=35350 ?

--Rik
by rjlittlefield
Fri Jan 08, 2021 5:34 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: mountain swallowtail
Replies: 9
Views: 410

Re: mountain swallowtail

best method (Lanczos3, Lanczos8, etc.) to interpolate the blue scales? At 50X NA 0.55, you're running at effective aperture f/45 (=50/(2*0.55)). Even for extreme blue wavelength 400 nm, that still puts the diffraction cutoff frequency at 18.2 microns per cycle. Against that, your camera has a senso...
by rjlittlefield
Thu Jan 07, 2021 3:51 pm
Forum: Photography Through the Microscope
Topic: Sea Urchin Spines SEM
Replies: 7
Views: 347

Re: Sea Urchin Spines SEM

Very nice!

I'm curious, what sort of preparation did these have to go through, in order to be imaged?

--Rik
by rjlittlefield
Mon Jan 04, 2021 8:18 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Windows of Papilio ulysses wing scale
Replies: 16
Views: 1765

Re: Windows of Papilio ulysses wing scale

I notice that one of the earlier links is now dead (https://core.ac.uk/download/pdf/12825066.pdf). But I found what I think is the same reference, via https://www.researchgate.net/publication/5495569_Sculpted-multilayer_optical_effects_in_two_species_of_Papilio_butterfly . The RIS citation and abstr...