MicrobeHunter.com Microscopy Forum

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...

The Quekett Microscopical club of UK (average age: 85 years old) have that streamlined and regularly hold auctions of lots from fellow microscope hoarders, similarly to the "pact" above. The Quekett's Estate Auctions website is accessible only for members, thanks to their young webmaster Alan Wood. ...

After a lot of thinking, here's my favorite - a 100x oil from about 1930. It even works, but I don't use it due to fear of damaging it (no spring mount..)
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Looks nice. What is needed to fabricate a real working darkfield condenser ? will it be dry or immersion (the Ultracondenser is immersion type) ? It is oil immersion (or also water for those with NA<1.3) It needs a 3D printer, some aluminium foil, a glass half ball as optics, a round coverslip and ...

Can also braze / solder a new handle to it, with the soldering iron and tin as for electronics

with some procrastination, I've added the add-on Zeiss dovetail - the worst and fastest design.... must be glued on the bottom of the "RMS" condenser
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for so long time I refrained from posting this masterpiece:
no thorough testing, but let's just assume that it is not good.
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In other words, could a cheap .40 version of that objective just be reshimmed internally to meet a .17 specification? The black top lens holder of the .17 protrudes about 1.5mm more than the .40; the chromed brass barrels look the same. I didn't dare to open them up . 20220309_120426.jpg . 20220309...

LomoBen wrote: ↑

Thu Mar 03, 2022 5:15 pm

OK, thanks.
For the moment I make not yet the decision to take it apart completely,but for now I think I have enough information.

Don't forget to take photos!!

Thanks, no rush, I was hoping that there is just "one" most common condenser mount... instead there is one "Standard", another "Universal", and many more :lol: Any model is good; it is just to make the 3D design ready for future generations; it doesn't take much time for me to draw a couple more dov...

the spring, it is to keep the coverslip adjustment tight To take out the adjustment mechanism, you don't need to remove the cap with 85x; the moving barrel comes out from the top. Need to screw out the black baffle (likely stuck as well) and the ring underneath. And loosen the grub screws in the sca...

Oh sorry just read the "correction collar manteinance" link at post #1 The link for the 40x repair, that is much better than my instructions, and 40x has identical construction than the 85x. Below, some scuffs on the cap. Not sure if it was me or previous owners. so, wait for the oil to do its job....

I've disassembled this objective a few months ago, doing a bad mistake. You don't really need to disassemble anything. Try with light oil as from previous post (and wait overnight...). very important : take plenty of PHOTOS of the coverslip thickness scale, mark where it is, mark where the ring is, ...

Apart coverslip holders annealing (and maybe a compressor..) I'm working a bit more on the condenser, will make the base to fit other stands. Could somebody help me with the dimensions? I have only the ancient Swift and the Leitz dovetail, and can't find reliable data on the sizes of other makers. N...

think I've seen it but forgotten
the magnets, seen just now...

Mc Crone day
found this article "An afternoon with mr Footswitch"
a clearly disturbed individual using light foot switches, to examine under microscope the debris found on roads...

https://www.mccrone.com/mm/confessions ... switch/

For reference, just found this article from Ted Clarke, about spherical aberration of the condenser. His conclusion, the SA issue can be patched by keeping the field diaphragm fully open (in Köler illumination) Or, I'd say, by using a non-kohler large and diffuse illumination before the condenser. h...

If can be of inspiration, here a rather laborious, machined darkfield stop holder for Olympus, from the later resourceful Ted Clarke

https://www.mccrone.com/mm/machining-a ... denser/

It is possible, the threads about PlasDIC are very long, likely somebody sorted that out there.

In reflected, is it the same prism that shears and ricompose the image?

Thanks, good, so foam tabs shall be.
I have a Leitz #400 condenser, and really liked your idea to put the darkfield stops up inside, near the original iris. Why not the lollipops? Too difficult to change, or not so critical?

I think the shear is set to be about equal to the resolution, or a bit less. Not from hard mathematical formulas, but a tradeoff choice: - more shear, makes stronger contrast - but too much shear, makes the image double and loses resolution So if Rayleigh resolution is 1 micron, appropriate shear wo...

those are really nice inserts, congratulations!
is that Eva foam tab for the tight fit in the bore?