A rougher version of previous post
Just a black pencil ("Sharpie" ot others) on slide, leaves some tiny holes often suitable for star test.
The metallic mirrors are better though.
Search found 402 matches
- Sun Sep 10, 2023 6:42 pm
- Forum: Digital processing
- Topic: measuring psf without fluorescence
- Replies: 12
- Views: 3789
- Sat Jun 10, 2023 9:06 am
- Forum: Beginner's corner
- Topic: Image separation behavior in through-focus range of a microscope objective lens
- Replies: 5
- Views: 1642
Re: Image separation behavior in through-focus range of a microscope objective lens
I'd vote as well astigmatism (and/or coma)
it happens on the center of the field, so there may be miscollimation or misalignment of some lens.
You can raytrace with zemax and other, shift or tilt one of the lenses off-axis
it happens on the center of the field, so there may be miscollimation or misalignment of some lens.
You can raytrace with zemax and other, shift or tilt one of the lenses off-axis
- Tue May 30, 2023 6:51 am
- Forum: Microscopy accessories
- Topic: Objective caps
- Replies: 5
- Views: 3233
Re: Objective caps
Can 3D print those models
(or order them from Craftcloud)
https://www.thingiverse.com/thing:4568767
They work; won't be as good/cool as the Olympus!
(or order them from Craftcloud)
https://www.thingiverse.com/thing:4568767
They work; won't be as good/cool as the Olympus!
- Wed May 24, 2023 8:30 am
- Forum: Illumination Techniques
- Topic: Types of Phase Contrast and when to use which type
- Replies: 12
- Views: 2883
Re: Types of Phase Contrast and when to use which type
I fear that all this beautiful variety of phase contrast methods has disappeared, and today ony standard "bright" setups are normally available - with no indication wether is High, Medium or Low like in the table linked above. The trouble with pond life, is that there is a bit of everything; I have ...
- Mon May 22, 2023 10:46 pm
- Forum: Beginner's corner
- Topic: Subjects and method for dry mount, no cover slip?
- Replies: 8
- Views: 1799
Re: Subjects and method for dry mount, no cover slip?
While trying to mount diatoms, I've tried this: Filter pond/seawater with coffee filter squeeze the the result on the glass let it dry If the sample was nice there will be full of algae and microrganisms, stuck to the glass. Usable; with coverslip then gets better and more robust. Did you try Uni-Po...
- Mon May 22, 2023 6:34 pm
- Forum: Illumination Techniques
- Topic: Is Dark Field Possible at 100x with Immersion Oil?
- Replies: 25
- Views: 16097
Re: Is Dark Field Possible at 100x with Immersion Oil?
It is also relatively easy to do "opposite df" with the condenser outputting small NA (like 0.5) and a central stop patch placed inside the objective, so the direct illumination is stopped. With this method, objective NA can be as high as will; darkfield is dark; but there are horrible diffraction a...
- Mon May 22, 2023 11:35 am
- Forum: Illumination Techniques
- Topic: Is Dark Field Possible at 100x with Immersion Oil?
- Replies: 25
- Views: 16097
Re: Is Dark Field Possible at 100x with Immersion Oil?
In case of interest- and lacking budget for the above mentioned Nikon 1.43-1.20
my "ball" oil df condensers are still on sale...
Max objective NA revised down to 1.25.
I should warn that DF at such high NA works only for very thin and clean specimens - things thicker than like 2 micron make a mess.
my "ball" oil df condensers are still on sale...
Max objective NA revised down to 1.25.
I should warn that DF at such high NA works only for very thin and clean specimens - things thicker than like 2 micron make a mess.
- Thu Apr 20, 2023 5:30 am
- Forum: Microscopes and optics
- Topic: Schmidt objective
- Replies: 4
- Views: 1129
Re: Schmidt objective
Oh remembered, I've made a similar setup time ago: observing a small spherical mirror with 4x objective. No confocal, immersion nor two-photons. Immersion could be done with a chamber, but not easy to put the microscope horizontal (oh wait, the old horseshoe stand tilts) How to make the spherical mi...
- Thu Apr 20, 2023 5:06 am
- Forum: Microscopes and optics
- Topic: Schmidt objective
- Replies: 4
- Views: 1129
Re: Schmidt objective
That is very nice, I like the idea of using the immersed mirror as main magnification element - so it doesn't care about the refractive index of the immersion medium. Their application is looking inside larvas of fish - pretty thick and irregular specimen, so they want to match the index of the refr...
- Thu Feb 02, 2023 3:00 pm
- Forum: Illumination Techniques
- Topic: Testing high NA darkfield condenser
- Replies: 58
- Views: 19288
Re: Testing high NA darkfield condenser
Too late, the 3D print bug hit again: Plastic dummy slide, coverslip holder 2.0 They're plastic, not so stiff, and they soak up water and oil. But sit flat and the slide can be put flush over the condenser or the objective. Two model, the one on the photo need a dab of glue to fasten the coverslip. ...
- Mon Jan 30, 2023 9:09 am
- Forum: Illumination Techniques
- Topic: Testing high NA darkfield condenser
- Replies: 58
- Views: 19288
Re: Testing high NA darkfield condenser
Voila, here too, making those Cobb slide from a beer can, sorry for disregarding the previous suggestion by chas, and thanks MichaelG for the video link! the aluminium is a bit too thin, like 0.1mm, while the one used in the video linked above looks much thicker (0.5mm?) It is difficult/impossible t...
- Sun Jan 29, 2023 5:55 pm
- Forum: Microscopes and optics
- Topic: Ancient Leitz Wetzlar darkfield condenser
- Replies: 18
- Views: 3839
Re: Ancient Leitz Wetzlar darkfield condenser
Oh my gosh so cool things those ancient setups!!
- Sun Jan 29, 2023 12:10 pm
- Forum: Microscopy accessories
- Topic: Olympus objectives
- Replies: 2
- Views: 2528
Re: Olympus objectives
(unserious post, rainy Sunday) I don't have either, but sure bet that the more expensive ones are better. A discussion with the wife or a check on the bank account may help to take the right decision. Me, at the prices they are going I'd rather buy a boat and get some rare samples from deep and offs...
- Sat Jan 28, 2023 10:39 am
- Forum: Illumination Techniques
- Topic: Testing high NA darkfield condenser
- Replies: 58
- Views: 19288
Re: Testing high NA darkfield condenser
About funnels, I take the bait to advertise one of my earlier DYI - 3D print creations https://www.microbehunter.com/microscopy-forum/viewtopic.php?f=28&t=14262 Sure brass would be better than plastic, but now I have funnels for almost all objectives. The centre stop/inverted darkfield/dispersion st...
- Thu Jan 26, 2023 12:34 pm
- Forum: Microscopes and optics
- Topic: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
- Replies: 14
- Views: 5419
Re: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
The patents are not bad - there is both some good substance and some nonsense mixed in, but overall show competence in the field and are quite explanatory (while often patents are purposefully incomprehensible). However I couldn't grasp what is being patented exactly. I stop here because of time con...
- Thu Jan 26, 2023 11:20 am
- Forum: Illumination Techniques
- Topic: Testing high NA darkfield condenser
- Replies: 58
- Views: 19288
Re: Testing high NA darkfield condenser
My condenser ain't anything special, and don't think it is better than a normal cardioid. It is what I could make quick by myself with the materials at hand (half-ball lenses) instead of getting gouged on ebay for some antique Ultracondenser. Perk is that it can be made with very high NA, the last p...
- Thu Jan 26, 2023 8:00 am
- Forum: Illumination Techniques
- Topic: Testing high NA darkfield condenser
- Replies: 58
- Views: 19288
Re: Testing high NA darkfield condenser
Two questions I still have about this condenser is regarding it's focus and chromatism? In every other DF condenser I have come across, great lengths were taken to pass the light through using finely polished mirrors and glass components, whether lenses or blocks. In this condenser the reflecting s...
- Wed Jan 25, 2023 11:36 pm
- Forum: Microscopes and optics
- Topic: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
- Replies: 14
- Views: 5419
Re: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
About the mad idea of apochronaut of "stretching" an high NA objective to longer working distance I've played a lot with refocusing the tube lens, that does this stretching. Results usually poor in my case. Yes, I guess too that increasing the working distance reduces NA. How much? Let's take as exa...
- Wed Jan 25, 2023 10:52 pm
- Forum: Microscopes and optics
- Topic: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
- Replies: 14
- Views: 5419
Re: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
Ok so I've (partially) read some from the site and some from the patents this infocus is a focusing lens. Like moving the tube lens. Many here have done more or less the same with the "poor man infinity", using as tube lens a (focusable) camera lens. Also similar effect can be achieved in afocal pho...
- Wed Jan 25, 2023 8:30 pm
- Forum: Microscopes and optics
- Topic: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
- Replies: 14
- Views: 5419
Re: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
sorry I've read only now the previous linked thread.
don't know now. I think Hans was right. Posts #2 and #3 start seeming reasonable.
don't know now. I think Hans was right. Posts #2 and #3 start seeming reasonable.
- Wed Jan 25, 2023 4:23 pm
- Forum: Microscopes and optics
- Topic: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
- Replies: 14
- Views: 5419
Re: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
By the way, variable spherical aberration correction is also common in camera macro lenses, that have a further "floating" lens that moves when focusing: such that when the lens is focused near, the spherical aberration (and maybe others) are corrected for that focal distance. Similar to the "correc...
- Wed Jan 25, 2023 9:20 am
- Forum: Microscopes and optics
- Topic: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
- Replies: 14
- Views: 5419
Re: InFocus™ Dynamic Optical Focusing Systems (tubelens on steroids)
The marketing material of Margolis are sure a bit over-the-top rants, but I really like the guy and its designs. That are quite simple at the end, but as written above, it is in business, so there are costumers willing to pay for a ready made working system. I'm a big fan of black enamel, while desp...
- Wed Jan 25, 2023 8:49 am
- Forum: Illumination Techniques
- Topic: Narrow wavelength blue filter
- Replies: 3
- Views: 1987
Re: Narrow wavelength blue filter
A bit late on retail, there are filters for Astrophotograpy; not cheap too https://www.baader-planetarium.com/en/filters.html Otherwise you can use a blue LED - more energy efficient! And they have pretty well defined wavelength and narrow band. I use the screen of my phone (OLED), displaying a pure...
- Wed Jan 25, 2023 8:24 am
- Forum: Illumination Techniques
- Topic: Phase Contrast condensers.
- Replies: 10
- Views: 3088
Re: Phase Contrast condensers.
So summary: - Condenser oiling has no direct effect on phase contrast - In the 1950's the first Phase systems used oiled condensers just because that was the norm - Later, high NA dry condenser came along, and today (I think) all commercial phase condensers are dry - High NA oil objectives can be us...
- Wed Jan 25, 2023 8:01 am
- Forum: For forum members who want to buy and sell equipment
- Topic: Leitz Phaco condenser centering keys - trade /swap
- Replies: 4
- Views: 1841
Leitz Phaco condenser centering keys - trade /swap
To vintage Leitz owners I have two extra keys for centering the Phaco condenser (Leitz 402a turret) Those are not the original unobtanium Leitz tools, but watch keys #5; they fit perfectly and do the job. Only defect is that they're so small, easy to be lost. I will send them as letter; plz provide ...
- Wed Jan 25, 2023 7:38 am
- Forum: Illumination Techniques
- Topic: Testing high NA darkfield condenser
- Replies: 58
- Views: 19288
Re: Testing high NA darkfield condenser
AO dovetail coming... I've taken back this project, and, dismal discovery, wasn't really NA 1.4 :oops: One of the testing objectives - CARL ZEISS JENA 60x 1.40 - upon closer observation turned out to have NA 1.3-ish, not the stated 1.40. I'm in good company about NA cheating... If somebody has a cal...
- Wed Jan 18, 2023 4:30 pm
- Forum: Illumination Techniques
- Topic: Phase Contrast condensers.
- Replies: 10
- Views: 3088
Re: Phase Contrast condensers.
So weird, I thought of oiling the condenser as something exotic and innovative... instead it was the old standard!
- Wed Jan 18, 2023 1:09 pm
- Forum: Illumination Techniques
- Topic: Phase Contrast condensers.
- Replies: 10
- Views: 3088
Re: Phase Contrast condensers.
My take on why Oiled phase condensers are not common (never thought about before today): The illumination, the phase annulus has NA much smaller than the objective : for an oil objective with NA 1.25, the annulus (the hollow cone illumination) is like 0.7-0.8, so there is no need to oil the condense...
- Fri Jan 13, 2023 2:04 pm
- Forum: Beginner's corner
- Topic: Polychromatic polarization
- Replies: 28
- Views: 10259
Re: Polychromatic polarization
I've just discussed with others this "polychromatic stacking", as post #17, and in order to convince them that it's legit I had to make some more decent images: small chunks of Mica fibers of polyester both at 4x NA 0.10 It also turned out that this method has been presented already in the 90's. Any...
- Wed Jan 11, 2023 11:28 am
- Forum: Resources (online, books etc.)
- Topic: Citizen Microscopy
- Replies: 15
- Views: 5943
Re: Citizen Microscopy
Big battle:
Linear aperture (telescope diameter)
vs
Angular aperture (microscope NA)
Both lead to a crave for flat field, fluorite apochromat objectives.
Linear aperture (telescope diameter)
vs
Angular aperture (microscope NA)
Both lead to a crave for flat field, fluorite apochromat objectives.