MicrobeHunter.com Microscopy Forum

There were somewhat similar illumination systems made for DF use,, with a low wattage incandesdent bulb embedded inside a DF condenser.

User name should be Spermatozoa not Protozoa.

I started wearing a tintoil hat when I eat Tuna. Then all my fillings fell out. Turns out I bought an industrial tinfoil hat, the kind that thermometer recyclers and chlor-alkali workers use : 18 gauge. You can be too cautious. All I really needed was a diy tinfoil hat made from Reynold's wrap. Deve...

I don't know whether Leica continued with the Reichert and AO toric condenser or not. It is kind of a W.F. DF condenser and can cover a 2000 micron field, so can be used with a 10X objective and 10X/20 eyepieces. That would be the DF condenser to look for.

Hope it all works out for you. I use a somewhat similar condenser on a B & L Balplan Research stand. The chief engineer of the Balplan made a 125X 1.40 Flat Field Apochromat prototype and he and a colleague patented a really nice compatible condenser to go with it but I have never seen an example of...

All DF condensers or condensers modified to produce DF have limitations, so understanding those helps one to choose which method is most suitable. Obviously, using stops and an existing available condenser is the cheapest option. Stops are o.k., even good with up to a 20X objective and possibly high...

If you ever plan on doing high resolution DF you will need the iris.

Guessing but seems so. It is probably a very good condenser for higher N.A. objectives but it was for a microscope that utilized a mirror and remote illuminator, so it has a longer front focal length. It would work better on a microscope with a rear mounted illuminator, collimating optics , field di...

It was pretty hard to improve on a 1.40 achromat aplanat and most companies didn't need to because their objective range seldom exceeded a 1.40. Winkel made a 1.52 condenser in the 50's/60's. Leitz probably made that or a very similar condenser for 40 years, eventually marking the an N.A. on it. Lei...

Leica was not a microscope company until the 1991 merger. This condenser easily could be Leitz but not Leica. It is not a DF condenser.. It is a stacked BF condenser with sectional N.A. increases matching that required by the grouped objectives coupled to it's matched system. A DF condenser has to h...

I use what is likely an ancestor to the 40X 0.75 Fluotar fairly regularly. If it isn't , Leica would have used it as a prototype, if they didn't think they could make something even better otherwise, so the HCX 40X 0.75 Fluotar is probably at least as good as what I am using and notable due to W.D. ...

So then, might that not be pre-war Zeiss or possibly ROW? Weddig was in what became East Germany too.

The way I have typically branded condensers is stylistically. Comparing lettering, knurling and lathing and if available the design of the iris handle. None of that checks any boxes for me plus there were a considerable number of German makers. I have to assume it is German. Interesting stacked desi...

I would say not chromium and probably a nickel alloy. Some version of what was at the time called German Silver. Copper, nickel and zinc in varying percentages ,, depending on who made it and what it was made for. It was widely alloyed in Germany after about 1870 or so., used frequently where a brig...

Chromium plating for commercial use was exclusive to the U.S. until after 1925. Although some small parts were plated in the early 20's, they didn't start using chrome for things like automobile bumpers until around 1927. I have a brand new # 7 objective of that same form as your 6, identical to the...

Finally, regarding the defocused Abbe condenser, I don't normally use an Abbe condenser either but remember reading somewhere how the large spherical aberration prevents filling the entire NA range of high-magnification objectives at any single focus setting. Perhaps the specific defocus setting yo...

Is the 6 not just a partial? Leitz shorter focal length objectives could be separated, so that a funnel stop section or iris diaphragm section could be threaded into the lens section. Likely 1920's based on the knurling and brass. Chrome plating wasn't used prior to the early 20's. Lacquered brass w...

Sometimes the objectives are very short, only about 1 cm. long. These were usually used when a vertical illuminator was placed between the objective and microscope body tube. Since the vertical illuminator increased the tube length, the upper part of the objective barrel which in the pre-plan era wa...

On chemical microscopes met. microscopes and polarizing microscopes there were seldom revolving noepieces in the early days, up into the 1950s or even 60s. In order to speed up the changing of objectives a quick change mount was employed, each of which included centering screws so each objective cou...

Thanks! The scales were very evident, almost reptilian.

I can see where they are trying to go business wise. Every company, especially one that recently underwent changing of the guard , sits down and sets a course at critical junctures. Some very formerly well placed and innovative corporations did not do that effectively : Polaroid, Kodak. Had they see...

Zeiss coated optics cleaner spray. For when you assume the coating is damaged after isopropyl meths soapy didn't work. Meade and Takahashi apparently don't trust it on their coatings. There are reports of it damaging the coating on astronomical instruments. It's target market may be eyeglasses whic...

Thanks. I probably haven't seen a Lacrymaria then. I see these swan necked ciliates occasionally in habitats that I would suspect to be fairly nutrified. I didn't know to speciate them by the mouth and it is hard to by proboscis length, since they can stretch them. I tried to catch the mouth in focu...

There two scenarios. One is the fungus is growing on a film or fine airborne debris deposited on the glass or two is on the coating. Since almost all optics have been coated for many years now, I assume it is on the coating. If the microscope is older you might be lucky and it is on glass only. Some...

I agree. Plus, acetone can dissolve some substances you don't want dissolved if it gets into the wrong place.

This is the other big fish in the little pond. #'s 1 and 2 I first thought a rotifer but is likely an Icthydium at full steam ahead. I was unable to capture a good image of it's lateral feelers, or what appeared to be feelers or bristle sensors extending out from it's head. Visually it looked to hav...

These were found in a fairly fertile sluggish creek crossing a farm. It is being fed a bit from cattle manure. Although the temperature is still quite cold, there is a thick cap of algae and much activity This is a Lacrymaria about 200 microns long. The first is 2 are 40X .66 Plan Achro Dark Phase. ...

My post really wasn't about Abbe and I don't doubt whether he understood basic physics or not. I don't think Zeiss would have kept him around if he was lax in that department. He undoubtedly guided Zeiss towards incorporating condensers into their better microscopes and of course had the most ubiqui...

Resolution is affected by multiple elements. An N.A. .90 cone of white light is modified differently when passing through a .90 N.A. objective than when passing through a 1.40 N.A. objective. It also splits at the front lens and does not behave like a monochrome ray does in a simple illustration as ...

Could you point me to Harry's point about DF, I missed that too.