MicrobeHunter.com Microscopy Forum

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. ...

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...

Oh my gosh so cool things those ancient setups!!

(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...

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...

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...

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...

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...

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...

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...

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.

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...

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...

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...

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...

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 ...

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...

So weird, I thought of oiling the condenser as something exotic and innovative... instead it was the old standard!

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...

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...

Big battle:
Linear aperture (telescope diameter)
vs
Angular aperture (microscope NA)

Both lead to a crave for flat field, fluorite apochromat objectives.

Just a side warning, I've bought "0.4mm" coverslips a while ago from China, "Sail Brand" I think, they were very cheap but also quite crap: thickness random between 0,30 and 0,50mm, and every-single-one well dirty, I had to wash them. Maybe I was unlucky with a bad batch, I can't imagine a technicia...

I'm taking saltwater samples often, and they vary a lot: often nothing, while sometimes they packed full of different swimming beasts. Agree with previous post, muddy water is likely barren desert. One strategy is to follow the fishermen: when and where there are fishes, there are also micro algae a...

wow they're beautiful, thanks for the photos!

Something crude can be done with 3D printer

Modern alternative is a stop made of an LCD screen with pixels, so can be adjusted with many configurations. It has been implemented also with micromirrors. Or a light source made of a LED array, placed at the condenser iris position. Goes under the name "structured illumination" If somebody is inte...

very nice, so simple and compact; 10x 0.50 is a beast!

Since the sand grains are so large, I would sieve the sample and weight the fraction around 800 um. Depending what else you have in the sample. It may be possible to simply wash the sample with a lot of water; the heavy sand particles aren't washed away and settle on the bottom. Dry and weight. If y...

I'd say that the large vacuoles are just air bubbles; the small grains are the fat granules. It seems that the fat granules assemble at the surface of the bubble, due to surface tension/van der waals; or the thick border is just an optical effect from defocus/refraction/phase. The granules inside th...

Some random comments to sway further the subject: - The "Back Focal Plane" is not well defined in the objective itself; objectives don't usually have an aperture stop (!!!) The max light cone is stopped somehow by all lens rims; I'd take as official BFP the image of the condenser iris. Only occasion...