MicrobeHunter.com Microscopy Forum

A few years ago I picked up a Lomo 7x. It's marked for luminescence work ("Л"), but there's no tube length or cover slip correction noted. When I got it, I put it on a Zetopan and could not get it focus. It looked too old to be an infinity objective, but I didn't pursue the matter further. Today I p...

I would suggest setting up the HMC slits and leaving them alone. The effect is changed by rotating the light source polarizer, not moving the slits. When you view the slits through a phase telescope, after they have been properly aligned and brought together to overlap, you should see a black band, ...

Someone should be severely punished for doing that.

The simplest approach is probably a buckblock, the main downside being they max out at 2100ma so you can't drive e.g. a Cree XP-L at full power, but they still run very bright. Otherwise implementation is incredibly easy. Agreed. I use a couple versions of the same made by Keystone that are program...

Idflan - does that mean you would recommend PWM? Or just do 25kHz if I go that route. That’s good info and appreciate it. Also, I planning to under-drive a 10W LED. So I can adjust accordingly. I have 3200K and 15000K white LEDs in a bin for a previously project. I do have a light meter and I can m...

You want a PWM with a refresh rate of 25kHz or better to avoid banding on digital cameras. I'd also recommend using an LED without a lens, to avoid introduction of CA. Luminous panel type LEDs seem to work better for me in that regard, anyway. If you do that, 5W may not be enough light, depending on...

I am not sure I understand your question correctly, so I will answer it two ways. If the sample is colored or stained, then those colors remain in the HMC image (as in the case of DIC.) HMC does not induce interference colors like DIC prisms can, so the field is always gray to white (assuming you ar...

I am glad you had me take some pictures, because it allows me to correct my faulty memory. Aging sucks. Here is a set of pics. https://www.yogile.com/6cg8k2fmeb9/21m/share/?vsc=d5c26cfec The condenser slits get larger as you go up in magnification, like DF patches. It's the condenser slits that don'...

The condenser slits are different sizes for each objective. But there is a fair amount of tolerance - they don't seem to need to be exactly the right size to get some HMC effect. I'll take a few pictures of the condenser slits for you in a bit.

I doubt that 15% transmission rating for the polarizing film is an absolute must. I would give it a try with whatever linear polarization film you can get. The 1% transmission area of the Hoffman slit (marked on the website you reference as "D") can be omitted, at least at the objective rear. I know...

I see! You are combining circular and linear polarization... at one edge fairly high up in the optical train. I have no clear idea what that is doing... To get a real HMC effect, your condenser polarizer should be a reverse match for the slit version you made for the position above the objective. Th...

I think you must be mistaken about the 3/4 perimeter not varying. Just rotate the condenser and light source filters against one another and you will see what I mean. The area that is cut out of the condenser filter cannot vary in intensity because only one polarizer affects the light that goes thro...

Thanks for posting the videos. To my eye, the VAC2 setup seems to be giving a much better result than the modified system; the modified system's results seem very similar to normal oblique lighting. When you rotate the light source polarizer on the modified system, it pretty much seems to dim across...

I probably didn't explain my understanding of VAC well. I do understand that the central patch stays black. I think it could however be varied as explained, if one wanted. No, the cut out area of the main filter is not the variable area of light transmission. The area of variable light transmission ...

Proof is in the pudding, as they say. What do the results of your simplified VAC system look like? I haven't made a VAC system, but I am planning on it and have thought it through. VAC is not a contrast enhancement system based on interference effects. It is really a very fancy oblique lighting effe...

I was poking around the web for a good price on Acriflavine when I stumbled across a place out of New Jersey called "Dawn Scientific." They have a pretty good selection of stains (including the German production of Astra Blue that I just ordered from the UK at the same price, $6 per gram...) and (im...

I use selected high quality resin chunks and dissolve them in artist's turpentine over a warm hotplate. Let it settle for a week or so, and the haze/dirt will be at the bottom of the bottle. Just use the top layer or pour it off to another bottle. No need to filter. Go straight from pure alcohol or ...

I would imagine finding one of those would be like finding hen's teeth. Cell phone. Amazing technology. Finding any particular Zetopan part can often take a long while and cost too much. That said, it shouldn't be too hard to find the wide field swing out lens. Based on the catalog information, it ...

JWW wrote: ↑

Wed Feb 08, 2023 2:33 am

Someday when you have time, I'd love to see a photo or two of it.

Here you go.

https://www.yogile.com/lkts7ygampi/11m/ ... =d5c26cfec

Does anyone have a complete Zetopan UV condenser for phase anoptral contrast with the swing-out lens? The two Zetopan UV condensers I have don't have the swing-out wide-field lens. I'd like to see a few good photos of it and the reason for wanting the photos. I'm unsure if the swing-out lens was mo...

"As a stop gap measure the Buffalo factory may have relabeled these objectives with the Leica brand. As noted this was a stop gap effort and the branding was painted on rather than etched into the objective barrel. Yes, the labelling would wear off. The product life cycle in this configuration was s...

... AO Biostar 1820s on eBay equipped with very high quality Leica LWD infinity-corrected phase contrast objectives with adjusting collars and matched condensers. I was just going by your high praise of the Leica objectives on those cheap Biostars. Now I see that the barrels are cheap and the paint...

The Biostar was never offered with Leica branded objectives, although it was infinity corrected so someone may have built a system with objective from an DM IRB. On this point I am positive you are wrong, to the extent that it matters. I never bought an 1820 from the manufacturer, but you frequentl...

You can do that, but LWD objectives hung on an upright stand are a very poor substitute for the real thing for many reasons. One is that settlement of detritus at the bottom of the well slide (at the same time as it is a "problem" for pond water gazers) is also a huge plus in an inverted scope for m...

True, there are tradeoffs, but the results can be far better than you might guess, even with LWD objectives. The coverslip wellslides are a bit spendy but if tooling around a large volume of pondwater is your jam (and that seems to be what the original post was trying to accomplish) then an inverted...

Are you making some, or having some made? These are frequently snapped off. I could use at least one myself...

"Inverted microscope is worth considering." +1 to that suggestion; I think it's probably a better overall alternative to water immersion objectives, if I am understanding your wants correctly. With LWD objectives, an LWD condenser, and chamber slides made of coverslip glass, you have a whole lot of ...

It's identified in the literature as designed for doing blood cell counts under darkfield illumination, hence the iris. Hemacytometers use a very thick cover glass (0.4mm), which may also explain "-" designation?

Oh, a mighty interesting wee chalcid, too! Seems to be a not-very-discriminating parasitoid and/or hyperparasitoid of many different hosts... How did you come across it?

I assume you are asking about infinity corrected objectives? If not, the Lomo water immersion objectives, though very old designs in fragile mounts, might meet your wants. The ones I know of are these: 85x 1.0 70x 1.23 Apo 65x 1.1 Apo 60x 1.0 40x 0.75 30x .65-0.9 There are almost certainly others. O...