MicrobeHunter.com Microscopy Forum

I would guess "image sharpness" is referring to focus not spherical aberration and this is pointing out an advantage of their implementation compared to older or less sophisticated implementations where the correction adjustment changes focus at the same time? It would be an "ideal method of focusin...

The acquiring, cleaning, learning, and repairing journey is half the fun to me. Same here, my general advice would be: The "Frankenstein" microscope idea doesn't really work as well as one might hope, and as imkap said, forget about buying a bunch of individual parts. Sometimes there are deals but ...

With a drop of Cargille Immersion Oil Type B directly on slide and coverslip on top. Looks sharper, at least. Still not great contrast but I'm not sure what is expected for that objective. The different colors of the chromatic aberration on the left and right sides of the image (more red and cyan o...

40X 0.65 should give a pretty bad (but maybe not that bad) image if used with no cover glass. Might be worth sticking a 0.17 mm cover glass on top of the micrometer slide with a small drop of immersion oil to get an idea how much of the haze is from the objective itself vs. lack of cover glass.

Interesting observation, I suppose the effect should be somewhat analogous to using a phase telescope or Bertrand lens for alignment, except of course it can't actually be used for phase alignment since it comes before the objective. What sort of water filter did the beads come from?

I don't think I can understand that statement. The NA is the product of the RI and the sine. Mathematically it is easy to prove that NA <= RI * sin(theta) is always true, so the NA can never be greater than the RI Yes, maybe I misunderstood the question, if the the NA set by the condenser aperture ...

the NA is defined as a sinusoidal function of the top angle of the light cone The sinus is maximal (1.0) when that angle equals 90°, when the NA equals RI. How can the condenser 'know' which media are applied? NA is not affected by the media applied to the condenser if the the selected NA is less t...

Looks close to these Cambridge Instruments and Leica branded "StrataLab" models on eBay:
https://www.ebay.com/itm/312568716638
https://www.ebay.com/itm/224445518547

If the adapter is somehow blocking off a significant portion of the aperture (leaving only an offset sliver near the periphery) maybe that could explain both the dimmer view and the lack of radial symmetry in the CA that Scarodactyl mentioned?

Bram, were those all taken with the same exposure settings? Oddly the full image through the camera port looks noisier to me but I don't notice much noise difference in the 100% crops.

Yeah, I think Lomonaut and I were seeing microplicae as described in the papers linked in post #5. The photos in the 1960 paper linked in the first post are the only examples I found claiming to show the endoplasmic reticulum with phase contrast. I couldn't access the 1958 paper by Fawcett and Ito t...

Yeah I have a set I bought used on eBay (don't know the original source but the slide labels and wood case look identical to the ones sold by AmScope and others) that has the granules real bad:
viewtopic.php?f=10&t=10885

Yeah, they are not always visible, or maybe not all cells have them over large areas? I looked through quite a few cells to find the examples above where the fingerprint-like pattern is visible and in focus simultaneously over a relatively large area. I measured roughly 500 nm spacing between the ri...

Oh, one other consideration: are the microscope, camera power supply, computer, monitor, and anything else connected to them via cables all plugged into the same power strip? Worth trying that too if they are not already.

Beautiful microscope and video quality, by the way, even with the flicker.

Unfortunately the flicker occurs periodically and at settings that otherwise function perfectly. When the problem occurs it's visible at all combinations of FPS, Exp, ISO and at lamp brightness levels. This seems like pretty good evidence against the flicker coming from the illumination. Maybe elec...

I also wondered about these patterns while setting up some phase contrast stuff I bought a while back. My first guess of endoplasmic reticulum was almost certainly incorrect then after some more searching I was thinking maybe microplicae: https://www.microbehunter.com/microscopy-forum/viewtopic.php?...

Shined a flashlight through some more condensers. Various AO/Reichert "Abbe aspheric" and achromatic/aplanatic condensers from several generations in brightfield mounts all projected the iris sharply near infinity. The 1205 turret with 1201 achromatic/aplanatic condenser was interesting, lots of var...

A camera with lens focused at infinity looks at the slide; the slide has a row of small pinholes, spaced ~1.2mm to each other. The condenser illuminates the slide from below, with iris closed to minimum. if the illumination is not parallel/telecentric, we'll see many "bokeh balls", for each pinhole...

Continuing from:
Condenser corrections aplanatic, achromatic, etc. -- which planes are they referring to?

A patent:
3,971,621 - A Method and apparatus for generating a relieflike contrast at microscopic images of a transparent phase object

Yeah after looking at some more stuff, definitely corrected for dipping I think. Changing illumination to get closer to filling the objective aperture and using a test subject that is darker overall with some bright spots (black permanent marker on the frosted end of a slide) makes the spherical abe...

That 1929 catalog says 0.18 mm cover glass for dry objectives and not critical for homogeneous immersion but nothing about water immersion that I saw. Gave it a quick try with and without cover glass. Not a huge difference but I think no cover is looking a little better. Need to do a more careful co...

Scarodactyl wrote: ↑

Wed Aug 04, 2021 7:38 pm

I have a modern 40x/1.0 water immersion objective and it is great. Water immersion is awfully nice overall.

Oh yeah I think I just remembered... this monstrosity?

Patent I was thinking of, haven't read it carefully:
3,971,621 - A Method and apparatus for generating a relieflike contrast at microscopic images of a transparent phase object

Yeah it is an interesting thought. I came across a patent or paper a while ago that I think was talking about using a fiber bundle (not necessarily ordered) cut at an angle to get smooth (vs. NA, like Dodt gradient) and uniform (across the field) oblique illumination without a normal condenser, prob...

Not sure which version, this ones looks like a normal objective as far as I can tell but not clear to me what "fitted to mountings for the Slit Ultramicroscope only" from that blurb I quoted would involve. I guess this is probably the normal version, assuming those were more common, slit ultramicros...

Snivelling apologies if you feel I have mis-used the term ‘coherent’ … call it ‘ordered’ if you prefer [ that is the sense in which I used it ] Sorry, just pointing out a possible confusion since it seems like these fiber plates are already assumed to be ordered by default (so I wasn't sure which m...

Fibres are usually coherent [i.e. the plate can convey an image] Note confusing terminology, for example from https://www.rp-photonics.com/fiber_bundles.html : Fiber bundles may be ordered or unordered. In the former case, there is a one-to-one correspondence concerning the arrangement of input and...

Thanks, I will give it a shot, have you tried one? I was not sure how generally useful it might be since I had only found it mentioned in the context of the slit ultramicroscope. Did some more searching, the 1929 catalog referenced by the Molecular Expressions page on the slit ultramicroscope can be...

Nice fabrication, looks professional, and thanks for pointing out those LED stage inserts, I hadn't come across them before.

Ah, missed what you were saying about the protective film... so they are cut at 0, 45, and 90 degrees but not sure which is which?