The best demonstration of image formation by a lens that I've ever seen in youtube:
Its insanely cool that the author of the video etched on chromium coated glass the patterns that he used for all the experiments!
Just thought others here might enjoy this video too.
Search found 74 matches
- Wed Nov 29, 2023 12:30 am
- Forum: Resources (online, books etc.)
- Topic: Image formation demonstration using concentric ring patterns
- Replies: 1
- Views: 1637
- Thu Sep 14, 2023 1:34 am
- Forum: Camera systems and imaging
- Topic: PAXCAM drivers
- Replies: 11
- Views: 7282
Re: PAXCAM drivers
I recently found out that a PAXCAM, modified as described in previous posts, works with Micro-Manager 2.0 (april version or newer, better yet, latest nightly bluild) using the bundled Lumenera driver adapter. There's a catch though, Lumenera's Infinity analyze (v7.1.1 or later) must also be installe...
- Fri Aug 11, 2023 2:44 am
- Forum: Identification help
- Topic: What are these small cells ?
- Replies: 2
- Views: 1472
Re: What are these small cells ?
Those appear to be fungal zoospores within a zoosporangium. Perhaps Saprolegnia?
- Mon Jan 09, 2023 4:51 am
- Forum: Camera systems and imaging
- Topic: choosing software
- Replies: 8
- Views: 5201
Re: choosing software
As far as I know, WINE does not have a USB emulation layer. You'd need to use a virtual machine (KVM, VMWARE or VirtualBox) if you want to run Windows software in a Linux host and have access to USB devices.
- Thu Nov 10, 2022 12:59 am
- Forum: Illumination Techniques
- Topic: dIY DIC
- Replies: 68
- Views: 39938
Re: dIY DIC
I've had some success using a single Sanderson prism for DYI DIC. Here´s a diatom lineup, from one of those Victorian slide makers, with a 10x LOMO objective: DSC_3854_small.JPG This is the result of translating the prism along its shorter edge (left to right across the interference pattern, see the...
- Wed Oct 26, 2022 2:19 am
- Forum: Camera systems and imaging
- Topic: PAXCAM drivers
- Replies: 11
- Views: 7282
Re: PAXCAM drivers
You are on the right path. Assuming that you have the same model that I have (PX-CM) the bytes from the original EEPROM are: address|content 0|0xC0 1|0x54 2|0x53 3|0x17 4|0x80 5|0x00 6|0x00 7|0x00 That's vendor_id=0x5354, product_id=0x8017 with device id and configuration bytes all equal to 0x00. Se...
- Mon Oct 17, 2022 7:38 pm
- Forum: Illumination Techniques
- Topic: dIY DIC
- Replies: 68
- Views: 39938
- Mon Oct 17, 2022 2:51 am
- Forum: Illumination Techniques
- Topic: dIY DIC
- Replies: 68
- Views: 39938
Re: dIY DIC
I found these LOMO? or whatever DIC prisms, the upoer bigger one has a circular glass and a secondary slit with another glass behind it. The lower has a clear squarish prism glued at the edges. Can I do a anything with these to obtain some form of DIC? b664492e0435492aa3988fc70a753490 The link that...
- Wed Mar 30, 2022 10:49 pm
- Forum: Microscopes and optics
- Topic: Dare I mention Russian stuff.
- Replies: 7
- Views: 2330
Re: Dare I mention Russian stuff.
Some thoughts about this. First, I second MicroBob's suggestion that perhaps the sleeves were swapped. I have a couple of Lomo 40x objectives, one for use with and one for use without coverslip: 20220330_170627_small.jpg I was puzzled by the poor performance of the coverslip version, until I got aro...
- Wed Aug 25, 2021 2:59 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Are you trying to do it with like normal prism sliders? I think that would be difficult - which is why Rathi used the open frame design. The sliders for this microscope are relatively large. The smallest one is l=80mm by w=30mm, with the constraint being on the width. Two stacked polycarbonate pris...
- Tue Aug 24, 2021 2:48 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Yes, it be good to know if that's the case. I've postponed work on this project for several reasons, one being that I need to re-design the prism sliders. My current 3D printed sliders did work for some tests, but they deform even when a small bending force is applied to the prism... and then don't ...
- Mon Aug 23, 2021 2:55 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
All that is needed is to place a piece of correctly oriented, unstrained polycarbonate in front of the condenser prism (between the condenser prism and the condenser lens) and the fringe patterns are shifted to allow proper adjustment. Such a simple answer to what seemed an intractable problem befo...
- Sat Jun 12, 2021 1:46 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Hi Louise, Is difficult to see in this picture: https://www.microbehunter.com/microscopy-forum/download/file.php?id=24397 Are the short edges of the prism touching the sides of the frame? What about the prism edge and the bottom of the frame? From that photo it looks like there is uneven bending, as...
- Fri Jun 11, 2021 2:02 am
- Forum: Pictures and Videos
- Topic: group of diatoms with a swarm of algae..
- Replies: 1
- Views: 1482
Re: group of diatoms with a swarm of algae..
Very nice video!
- Fri Jun 11, 2021 1:33 am
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Ah, ok jmp, thanks. Sounds like I'm trying too hard. I did post one pic of the two prisms together - 'Prism A+B'. Sorry, I didn't see the Prism A+B picture before. Though now that I've seen it, it appears to be the same photo as Prism B, right? I think I need to go back a step and try again. Also I...
- Thu Jun 10, 2021 8:39 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Hi Louise, Note that for a single prism the interference pattern that I obtain within crossed polarizers is asymmetric, without a dark fringe band in the center: https://www.microbehunter.com/microscopy-forum/download/file.php?id=24232 The interference pattern from above is similar to the one at the...
- Sat Jun 05, 2021 6:29 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
I haven't read up on the Sanderson prism theory, and skimmed parts of this thread, so I may be missing something obvious here, but do you really need to measure and replicate the exact same divergence angles as those used in the paper? Replicating the divergence angles from the paper is, in my case...
- Fri Jun 04, 2021 9:13 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Louise, I agree with you, the divergence angle equation is not the problem. I am clearly plugging in the wrong values for the variables in my attempt to replicate their angle vs screw displacement plot, yet I've not been able to put my finger on what exactly I'm doing wrong... it should have been pr...
- Thu Jun 03, 2021 4:00 am
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Some images of the setup I've been using for testing. The individual parts: 20210602_205101.jpg left to wright, top to bottom: filter tray with a polarizer, sanderson prism slider #1 (for the back focal plane), rubber bands, analyzer, sanderson prism slider #2 (between light source and condenser). B...
- Fri May 28, 2021 8:53 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
The contraption that I used to obtain the image of that interference pattern is extremely simple, and it did not involve the microscope or any complex optic setup: literally the prism sliders were directly stacked on top of each other, flanked by cross polarized filters. Just imagine two of these: h...
- Fri May 28, 2021 3:14 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
Built the second prism and slider. The interference pattern between crossed polarizers from the two prisms, stacked and aligned on their main prism axes, look like this now: two_prism_interference_pattern.jpg A bit wavy, the 2 screws were not pushing evenly on the prisms, but it approximates the pat...
- Wed May 26, 2021 1:50 pm
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
To clarify, the problem is not that the angles are negative but that the results that I get from that expression do not agree with the displacement-to-angle relationship depicted in the figure from their paper, unless I make the changes that I mentioned. I might have missed something though, its not...
- Wed May 26, 2021 5:06 am
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
(Continued) In the end I built a crude 3D printed slider to accommodate a prism of 70x16x2.38mm: slider_prototype.jpg It was quite interesting to see how the interference pattern changed as the bending force on the prism increased, when the prism was hold between a pair of crossed polar filters. Her...
- Wed May 26, 2021 4:38 am
- Forum: Illumination Techniques
- Topic: DIC Question
- Replies: 257
- Views: 3114935
Re: DIC Question
I've been experimenting with Sanderson prisms too, after going over the paper from Rathi et. al. I believe there is an error in the expression that gives the divergence angle: divergence_function.jpg The problem is that with r and l defined as in their figure (Fig. 1): prism_schematic.jpg the expres...
- Sun May 23, 2021 2:52 pm
- Forum: Specimens, samples and slides
- Topic: Mounting Medium for Mold?
- Replies: 1
- Views: 2415
Re: Mounting Medium for Mold?
Lactophenol coupled with methylene blue (cotton blue) seems to be the classic mounting medium used in mycology. Not sure if it can be considered a permanent medium though. Here's a page with some info about it: Lactophenol Cotton Blue (LPCB) Staining
- Fri May 21, 2021 3:03 pm
- Forum: Illumination Techniques
- Topic: Ptychographic Microscopy
- Replies: 8
- Views: 4497
Re: Ptychographic Microscopy
Just out today in Science:
Electron ptychography achieves atomic-resolution limits set by lattice vibrations
Electron ptychography achieves atomic-resolution limits set by lattice vibrations
- Thu May 06, 2021 7:41 pm
- Forum: Microscopy accessories
- Topic: Buying expired slides - hit or miss
- Replies: 17
- Views: 8247
Re: Buying expired slides - hit or miss
I had some very old but new slides that were also covered with a layer of some white residue, stuck together and cloudy, similar to what Hobbyst46 described. Tried to clean them in a similar way, and the results were similar. What made a difference though was polishing them with toothpaste; a larger...
- Thu Apr 29, 2021 12:29 pm
- Forum: Beginner's corner
- Topic: Could I see the bacteria in aquarium sustrate?
- Replies: 6
- Views: 2553
Re: Could I see the bacteria in aquarium sustrate?
Here's a link to a post in this forum where a member shared a set of filter designs for 3D printing.I will try to find how filters for oblique illumination are designed... maybe I can print them too
- Fri Apr 23, 2021 6:02 pm
- Forum: Illumination Techniques
- Topic: dIY DIC
- Replies: 68
- Views: 39938
Re: dIY DIC
Anyone else fancy having a go? Yes. I have an inverted microscope that provides easy slider access to the condenser and to the back focal plane of the objective. I have the original phase sliders and also a condenser silt slider (and polarizer). The slit slider is used in conjunction with a wolasto...
- Thu Apr 22, 2021 12:42 pm
- Forum: Pictures and Videos
- Topic: is Peranema an amoeba ??
- Replies: 10
- Views: 3561
Re: is Peranema an amoeba ??
Thanks Bruce. The motion of the euglenids is quite distinctive, that pellicle really imparts flexibility to this organisms; they are truly contortionists. I noticed that the movements of the organism in the OP's video were different, somehow less fluid, and clearly showed pseudopodia. Yet, its behav...