Search found 3454 matches

by Hobbyst46
Fri Jul 23, 2021 3:37 pm
Forum: Camera systems and imaging
Topic: 1st steps in Stereo microscopy
Replies: 9
Views: 187

Re: 1st steps in Stereo microscopy

Congratulations. Should be a great stereoscope. An instructions manual for this stereoscope is easily downloadable free, includes some troubleshooting tips. Possibly a maintenance manual can be had from Alan Wood - he is extremely helpful. You probably did not think of it anyway, but if so - better ...
by Hobbyst46
Thu Jul 22, 2021 7:45 pm
Forum: Microscopes and optics
Topic: Please advise, please offer comments on objective lens etched specs ed specs
Replies: 13
Views: 265

Re: Please advise, please offer comments on objective lens etched specs ed specs

Here is an example from the old Zeiss catalogue, displaying the same variety of significant figures:
by Hobbyst46
Wed Jul 21, 2021 9:35 pm
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

... ... Thank you both for the link and comments. Admittedly my previous claims are only relevant within the two popular (at least in microscopy texts) definitions of resolution. I agree that the width of the 90% to 10% decay is a reliable indicator of resolution for the image obtained under oil im...
by Hobbyst46
Wed Jul 21, 2021 4:43 pm
Forum: Illumination Techniques
Topic: DIC Question
Replies: 202
Views: 7327

Re: DIC Question

The paper has never been cited by anyone else. Agreed. However, the likely audience of her paper is hobby microscopists rather than researchers, and hobby microscopists apparently rarely publish papers... Her supervisor and/or corresponding author would know more about it. I am still crossing finge...
by Hobbyst46
Wed Jul 21, 2021 3:35 pm
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

However resolution is not everything. Contrast is as important. Illumination is important. I would assume that there is nothing wrong with the resolution of your microscope and start looking at interesting specimens instead. After some specimen-related adventures, one forgets about theoretical vs pr...
by Hobbyst46
Wed Jul 21, 2021 10:03 am
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

So the blue line represents the width of the frame in pixels. The other red lines just indicate the stage micrometer measurements. The entire field then, is about 0.062mm across. Each pixel at this resolution represents about 0.00001mm. The insert at 100% shows a line separated from the edge of the...
by Hobbyst46
Wed Jul 21, 2021 7:50 am
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

I see nothing in the posted photo to demonstrate resolution of two points separated by half a micron. What's wrong with the plot crb5 posted showing ~500 nm transitions at the edges of the lines on the calibration slide? There is nothing wrong with the plot, except that it does not indicate resolut...
by Hobbyst46
Tue Jul 20, 2021 9:57 am
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

MichaelG. wrote:
Tue Jul 20, 2021 9:33 am
I see nothing in the posted photo to demonstrate resolution of two points separated by half a micron.
Agreed, moreover the apparent resolution from that photo alone is 10 um... with the 100x objective as well as with the lower mag objective used for the whole ruler image...
by Hobbyst46
Tue Jul 20, 2021 8:19 am
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

At the highest magnification, (supposedly 2,500x) the field of view is 0.077mm Irrespective of the graticule and ruler and calculations above, may I suggest that x2500 magnification by means of a 100x objective, 2x Optovar and 12.5x eyepiece means "empty magnification" - namely, useless. Because th...
by Hobbyst46
Mon Jul 19, 2021 2:23 pm
Forum: Beginner's corner
Topic: Resoloution and Light Wavelengths
Replies: 37
Views: 596

Re: Resoloution and Light Wavelengths

Assume that your microscope is a Zeiss Standard (?) The width of the large image, the one that includes and shows most of the stage micrometer, is 1.27mm. Coast to coast. Because the micrometer ruler is 1mm long. I assume it has not been cropped (?). The eyepieces are described as 12.5x. Tried to ev...
by Hobbyst46
Sun Jul 18, 2021 1:18 pm
Forum: Home-made microscope adaptations
Topic: Mineral grains
Replies: 5
Views: 444

Re: Mineral grains

Decades ago, gluing a crystal to a rotating needle, such that its orientation in space was reproducible and defined along one of the crystal axes, was a standard technique of crystallography. The needle was mounted with plasticine (or similar stuff) to a simple goniometer head. Crystals were glued w...
by Hobbyst46
Sat Jul 17, 2021 8:08 pm
Forum: Miscellaneous
Topic: How really safe is a laser pointer ? new findings
Replies: 6
Views: 200

How really safe is a laser pointer ? new findings

I found the Off-Topic section locked (perhaps my ignorance) so I hope that the following will be OK in this topic. A recent post about the utility of laser pointers for the diagnosis of objective malfunction turned my attention to this recent publication: "Rare high-powered imaging enables detailed ...
by Hobbyst46
Sat Jul 17, 2021 8:13 am
Forum: Microscopes and optics
Topic: Simple method to test objective using laser pointer
Replies: 5
Views: 165

Re: Simple method to test objective using laser pointer

Thanks for the link. Unfortunately, the serious issues with my ~60 years old objectives are more in the internals, and lens coatings, than dirt on the front lens. Delamination can be revealed with a stereoscope. Although the authors of the linked article did not suggest it, I gave the laser method a...
by Hobbyst46
Wed Jul 14, 2021 10:15 pm
Forum: Specimens, samples and slides
Topic: Large diatoms in air, on a nail polish layer
Replies: 3
Views: 134

Large diatoms in air, on a nail polish layer

I received beautifully cleaned large Pinnularias and Surirellas from Northern Germany (thanks, MicroBob), that look under the stereoscope (60X) like 3D natural gems. Ordinary mounting in resin under a coverslip crashed them, in spite of the fairly thick layer of resin. So I tried mounting in air, in...
by Hobbyst46
Wed Jul 14, 2021 7:50 am
Forum: Pictures and Videos
Topic: Various amoebae
Replies: 9
Views: 238

Re: Various amoebae

75RR wrote:
Wed Jul 14, 2021 6:49 am
.
Nice set of sharp and detailed images. Good to see sampling location as well.
Likewise !
by Hobbyst46
Tue Jul 13, 2021 11:12 am
Forum: Microscopes and optics
Topic: Submicron imaging : 1998 style
Replies: 4
Views: 152

Re: Submicron imaging : 1998 style

Thanks for the link, Michael ! Enjoyable reading. Several points in the article caught my attention. 1. They used a 100X1.25 objective for darkfield. Apparently without iris, so the NA was still 1.25. The condenser was Ultracondenser, 1.2/1.4 oil. I personally have tried the same condenser model an...
by Hobbyst46
Sun Jul 11, 2021 9:02 am
Forum: Pictures and Videos
Topic: calcium oxalate crystals by precipitation
Replies: 4
Views: 184

Re: calcium oxalate crystals by precipitation

Very nice experiment !
Sometimes tiny crystals are formed when the solution contains crystallization nuclei - like dust particles, or when the process is disturbed by a mechanical shock.
But I doubt that any of these happened. Indeed, slow diffusion is the way to go, on a slide.
by Hobbyst46
Sun Jul 04, 2021 1:51 pm
Forum: Pictures and Videos
Topic: Pinnularia
Replies: 8
Views: 239

Re: Pinnularia

Very nice imaging ! and lovely sound accompaniment !
by Hobbyst46
Fri Jul 02, 2021 7:41 pm
Forum: Home-made microscope adaptations
Topic: DIY lamp house
Replies: 12
Views: 285

Re: DIY lamp house

Several notes. 1. A mercury bulb and a mercury lamp power supply are both irrelevant here. First, because a mercury lamp produces a blinding beam that is suitable to exciting fluorescence, when filtered to isolate discrete wavelengths. This light not only contains much harmful UV; its spectrum is ve...
by Hobbyst46
Wed Jun 30, 2021 10:35 am
Forum: Pictures and Videos
Topic: Amphipleura pellucida 95µm
Replies: 13
Views: 314

Re: Amphipleura pellucida 95µm

Found some interesting info on diatom mountant use: "Several different mountants with different refractive indices (R.I.) are available to mount diatoms for light microscopy but those with a high R.I. are generally best for mounting diatoms. For most diatoms high R.I. mountants provide greater cont...
by Hobbyst46
Tue Jun 29, 2021 10:11 pm
Forum: Pictures and Videos
Topic: Amphipleura pellucida 95µm
Replies: 13
Views: 314

Re: Amphipleura pellucida 95µm

Great demonstration of resolution, 75RR !
Hope to one day compare Pleurax with Naphrax on Pleurosigma and/or other as densely spaced stria as I can find.
by Hobbyst46
Tue Jun 29, 2021 8:49 am
Forum: Illumination Techniques
Topic: DIC Question
Replies: 202
Views: 7327

Re: DIC Question

hans wrote:...
I have been informed that at least one brand of PC for outdoor use is coated against UV, coating thickness can be 15-50 um, and may cover one side or both sides of the sheet, depending on expected market/site demands. FWIW.
by Hobbyst46
Mon Jun 28, 2021 12:10 pm
Forum: Illumination Techniques
Topic: DIC Question
Replies: 202
Views: 7327

Re: DIC Question

In the brochures of some sellers of Palram/Palsun products they state that Palsun includes a one-side UV protection. Some other PC sheets seem to carry double-side UV protection. I do not know what those mean, but I would suspect a UV-blocking coat layer of some sort. Would that affect the observed ...
by Hobbyst46
Mon Jun 28, 2021 8:16 am
Forum: Illumination Techniques
Topic: A question concerning resolution
Replies: 7
Views: 365

Re: A question concerning resolution

A "Funfox" home window coating is advertised as a privacy protection translucent (according to the photos) PVC layer, that electrostatically clings to clean flat windows and attenuates UV. Pin-holes or partial mirror surface are not mentioned AFAIK. Perhaps there are variants of this product ? A 1-2...
by Hobbyst46
Sun Jun 27, 2021 8:27 pm
Forum: Pictures and Videos
Topic: Diatomeen Ugchelen 6
Replies: 5
Views: 195

Re: Diatomeen Ugchelen 6

Very fine photos, I like the Pinnularia.

Several species of diatoms appear rectangular in girdle view; the cross section of (possibly Pinnularias) frustules on my stage right now is in fact square.
by Hobbyst46
Sat Jun 26, 2021 1:59 am
Forum: Collecting microscopes and slides
Topic: Leitz Laborlux K
Replies: 2
Views: 318

Re: Leitz Laborlux K

Hi y'all, I recently purchased a Laborlux K with the fluorescent attachment, however is missing the lamp power source. Looking at ebay I haven't been able to find one; is this something that can be adapted from another lamp light source.? Also the objectives are labeled PHACO, looking through them ...
by Hobbyst46
Fri Jun 25, 2021 8:29 pm
Forum: Microscopes and optics
Topic: 100X-1000X Trinocular LED Infinity Plan Phase Contrast Microscope + PLAN FLUOR
Replies: 7
Views: 336

Re: 100X-1000X Trinocular LED Infinity Plan Phase Contrast Microscope + PLAN FLUOR

Just guessing from the description and specs in those links. The thread of the plan-fluor objectives should be OK and the parfocal distance (DIN 45) should be OK. However, the field number of the microscope is 20mm, whereas the field number of the plan-fluor objectives is stated as 25mm. So you will...
by Hobbyst46
Fri Jun 25, 2021 12:03 pm
Forum: Pictures and Videos
Topic: Diatomeen Munster Bahnhof
Replies: 11
Views: 384

Re: Diatomeen Munster Bahnhof

Superb !
Were these images recorded afocally with the 12.5 KPL ?