Stage height adjustment of Leica DMLS microscope?

[PeteM]

I've just acquired a new-to-me (used) Leica DMLS microscope. While the scope looks in good shape, the stage comes several mm short of raising to full height. The objectives need to get that several mm closer to be in focus.

Anyone know how to adjust this? It isn't covered in the on-line manual I found. There aren't any obvious (to me) screws to set a stop.

Second question, which I'll eventually get to once the stage if fixed -- This Leica scope appears (?) to be the same family of 200mm infinity design as the AO Series 10 to Reichert 410 scopes -- and that by adapting long barrel lenses to the 25mm thread and by adapting a 410 trinocular head to the stand -- they'd work on this scope?

[lorez]

There is no user adjustment for the stage height, but it sounds as though the rack needs to be adjusted on the pinion. This is a bit complicated as it is most conveniently done through the ventilation port on the back of the arm.

As for the objectives, Leica seems to think that only those specified will work, but we all know that the whole purpose of a hobby is to take stuff apart and modify it.

Good luck.

lorez

[apochronaut]

The DM series of microscopes apparently used both HCX and HC objectives.
HCX M25 objectives are compatible with the earlier Delta R.M.S. optics( 1991-97), which are the same as the later R.M.S., D.I.N. AO/Reichert and Reichert Austria optics.
However, the HC M25 optics are not mentioned as being compatible with the Delta optics.

Those stated compatibilities come from the Leica website.

As far as using older AO or Reichert infinity corrected objectives. That is possible but only if the tube lens from an AO series 100 head was incorporated into a DM head or the entire series 100 head used on the stand. I don't know off hand , if the dovetail is the same. The 100 head can probably do about 24mm f.o.v., so there might be some problems at the Leica eyepiece end but AO 180 or the Leica equivalent would do.

[PeteM]

A quick update, in case others have similar issues.

On my scope, the rack is visible from the vents, but not accessible. After going in through the bottom (the illuminator assembly is in the way), I had an "aha." Turns out the stage height can be adjusted by running it all the way down (clearing the condenser carrier first) and there is a sort of slip clutch. Slip it all the way with the stage lowering to a hard stop and the stage returns to its proper height when cranked back up. Not sure if that's the Leica approved method, but it worked without damage.

Don't have a bulb yet for this but a quick check with a headlamp below showed an AO/Reichert 40x working just fine with an RMS to 25mm adapter -- as Apo said it would.

The lens that came with my scope are just Plan Achro's -- "C-Plan" series. A guess is that they're similar optics to the long barrel AO-Cambridge-Reichert-Leica equivalents for a standard RMS thread?

The dovetail on the Leica DMLS is 44.72mm while the AO/Reichert is around 50.4mm. Pretty sure I can turn down the dovetail on a Reichert Microstar IV trinocular head (which has a tube lens) and use it?

[apochronaut]

I think the way it went was the R.M.S. Leica infinity optics were developed out of existing designs AO and Reichert had cooperated on for some time. By 1990 AO had shuffled these out into what they called Neoplans and planachros, most of which were tweaked versions of the older 34mm objectives but some were clones of older Reichert D.I.N. objectives. The C. Reichert 10x .25 plan objective of the 70's, shows up as the Reichert U.S.A. 10x .25 Neoplan, pretty much unchanged, for instance. No doubt the planfluorites and planapos from Austria were included in what Leica called the Delta optics, too. Alpha would have been 170mm tube 37mm parfocal, Beta would have been 170mm tube 45mm parfocal, Gamma the 160mm tube 45mm parfocal and Delta the infinity corrected 45mm parfocal. The HCX optics apparently followed the same corrections but in order to accomodate the larger field requirement , they put them in larger diameter barrels, with larger threads. I have no idea why the HC optics are not compatible with the infinity R.M.S. Delta optics, yet are with the HCX, which are compatible with the R.M.S. infinity optics. Perhaps it just a f.o.v. issue. Obviously the M25 objectives are unlikely to be fitted to an R.M.S. microscope but the other way around would be likely. I think HC goes out to 28 and HCX, maybe only 25. Leica is very oblique, when it comes to explaining their philosophy on where corrections are best accomplished and just where there Harmonically Compatible corrections are taking place.

I'm unclear why you would need to put a Microstar head on the DMLS, Pete? The tube lens in the Microstar IV head would have the same corrections as the tube lens in the DM head, if the AO/Reichert optics work well on the DMLS. If you want to use the short AO infinity objectives , then you will need a series 100 head, which has the same 2" dovetail as the Microstar IV but different corrections. I occasionally use a lengthened 34mm AO U.S.A. objective in my Diastar( a dry 40x planapo .80 for instance...the Reichert D.I.N. version is oil imm.) but I swap over a series 100 head along with it. With the Diastar head, there is considerable lateral chromatic aberration and even axial chroma visible. It seems that the original AO infinity system had deliberate overcorrection in the tube lens, to compensate for something happening in the semi-objectives of the time.

[PeteM]

. . . I'm unclear why you would need to put a Microstar head on the DMLS, Pete? The tube lens in the Microstar IV head would have the same corrections as the tube lens in the DM head, if the AO/Reichert optics work well on the DMLS. If you want to use the short AO infinity objectives , then you will need a series 100 head, which has the same 2" dovetail as the Microstar IV but different corrections. I occasionally use a lengthened 34mm AO U.S.A. objective in my Diastar( a dry 40x planapo .80 for instance...the Reichert D.I.N. version is oil imm.) but I swap over a series 100 head along with it. With the Diastar head, there is considerable lateral chromatic aberration and even axial chroma visible. It seems that the original AO infinity system had deliberate overcorrection in the tube lens, to compensate for something happening in the semi-objectives of the time.

Apo - - thanks -- my thinking was that 1) I already have a spare trinocular Microstar IV head and that 2) it would have a wider field of view than the AO Series 10 trinoculars I have and 3) it would just look more like it belonged. I'd likely be using the 45mm Reichert infinity objectives or AO short barrel on extenders in RMS to 25mm mounts to supplement the "C Plan" lenses that came with the scope. What I'm missing is a 100x and anything approaching fluorite or apo quality.

Not sure I understood your point about the Diastar head (same as Microstar IV?) head. I think you're suggesting that the older AO heads had less chromatic aberration than the Diastar/Microstar IV heads -- or at least when using short barrel AO lenses? I'm really not sure if the Microstar IV head will have essentially the same correctons as the Leica DMLS once I set it into place.

I've only been at this for a half year or so and this might be a good time to correct or supplement my assumptions about AO/Reichert/Leica infinity microscope heads. My guesstimates based on the few scopes I've played with:

- The original series 10/20 heads are reliable, optically good, with only the slightly small field (18mm??) not to like.

- The series 110 heads have often come to me with detached prisms. I don't see them as a durable design; especially in the hands of kids.

- The Reichert Microstar IV heads have seemed robust enough, but use mirrors instead of prisms inside. Plus seems to be a slightly wider field of view. Minus seems to be they are a cost-reduced design that will be harder to keep clean over time. This head, when placed a few mm too high (dovetail didn't fit) did produce a decent 40x image. But since I was juggling holding the head and focusing, I didn't really pay attention to chromatic aberration and the like.

- Don't have any real experience yet with the Leica DMLS binocular head, other than to note the dovetail differences.

Would very much appreciate any perspectives you might have, since there is likely to be some mixing and matching as scope heads suffer the slings and arrows of kids using them.

[PeteM]

I might add that the Leica DMLS manual lists Leica HC PL Fluotar and HC PL Apo lenses as upgrades for the C, C Plan, and N plan lenses. I assume the C Plan lenses my scope came with are semi-plan.

The point of this is that the only official word I could find from Leica is that only the HCX lenses are backward compatible:

Leica Microsystems HC System
The Leica Microsystems HC system (Harmonic Compound System) comprises the optical components that have been matched to each other for optimal image generation and are involved in the correction of the optical aberrations: objectives, eyepieces, tube lenses, adapter for camera and TV.

HC
The objective is included in the HC system.

HCX
The objective is also compatible with optics of the past (Delta optics 1991-1997)


However, since this scope (the Leica DMLS) dates from 1995 and presumably the manual as well (with its mention of HC fluorite and apo lenses) -- one assumes that at least some lenses marked "HC" have the same compensations??

[apochronaut]

. . . I'm unclear why you would need to put a Microstar head on the DMLS, Pete? The tube lens in the Microstar IV head would have the same corrections as the tube lens in the DM head, if the AO/Reichert optics work well on the DMLS. If you want to use the short AO infinity objectives , then you will need a series 100 head, which has the same 2" dovetail as the Microstar IV but different corrections. I occasionally use a lengthened 34mm AO U.S.A. objective in my Diastar( a dry 40x planapo .80 for instance...the Reichert D.I.N. version is oil imm.) but I swap over a series 100 head along with it. With the Diastar head, there is considerable lateral chromatic aberration and even axial chroma visible. It seems that the original AO infinity system had deliberate overcorrection in the tube lens, to compensate for something happening in the semi-objectives of the time.

I think you're suggesting that the older AO heads had less chromatic aberration than the Diastar/Microstar IV heads -- or at least when using short barrel AO lenses?

No, It's not that they have more ca than the Microstar/Diastar head, it's that the tube lens in the series 10/20 and 100/120 heads has different corrections than the tube lens in the 400 series heads. If you plan on using the short objectives on adapters, you will need to use the matching head. Just have a look through one of your short lenses, with either of the earlier series heads and then through the microstar head. It will suffer from quite pronounced image degradation, through the Microstar head. The later AO D.I.N. objectives need much less correction, same as the Delta and HCX optics.

[PeteM]

Thanks, Apo. I was planning to use the later DIN optics.