Leica DM questions

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
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Awesomealgae
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Joined: Tue Oct 06, 2020 10:25 am

Leica DM questions

#1 Post by Awesomealgae » Wed May 12, 2021 11:02 am

Hi Everyone new to the forum just made a post in intro so I’m going to jump straight into my Tech question here.
I’m going to buy a superb well looked after DMRB from a ex-collegue. The microscope is Trans with DIC at 10, 20, 40 and 63x.

Prisms are as follows
10 = K2 & A
20 = K2 & C
40 = K3 and C
63 = K7 and D1

There is a 100x objective installed, this is a PL FLUOTAR 100x 1.3 oil which from research requires K4 & D prisms is that correct?
If I source a K4 there are some on EBAY will it work with the D1 prism?
I would ultimately like to Have a high NA >1, 63 and 100x when funds allow. From my research I know this requires a K4 and either D or E objective prism. Do these exist? Does anyone have one they no longer use and would be willing to sell? Or can anyone point me in the direction of someone who might?

Thanks so much for reading Dan

apochronaut
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Re: Leica DM questions

#2 Post by apochronaut » Wed May 12, 2021 12:21 pm

There is probably a manual on-line, that should give you some guidance or more than likely you can download one from Leica Microsystems.
Regarding the prism combinations. Perhaps a D2 for the 100X.
I have never encountered a 1.63 N.A. objective. Objectives of over 1.6 N.A. have been made going way back, possibly to the war years, exoerimentally. Kodak, patented at least one of very high N.A. , 1.6 or something like that but the problem becomes one of maintaining a homogeneous condition. Coverslip glass needs to be that high and the immersion medium needs to be something like methylene iodide plus a 1.63 N.A. light source. I had a methylene iodide immersion 50X Leitz objective once but no methylene iodide.
The highest N.A. objective that Leica makes or rather that I know of is a 100X 1.44 oil with a correction collar in the HCX series. I have seen 1.45 oil objectives from other makers and once a 1.52 N.A. condenser.

PeteM
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Re: Leica DM questions

#3 Post by PeteM » Wed May 12, 2021 1:09 pm

That will be a wonderful scope - congratulations.

There is a listing of Leica HC objectives online that lists the prism combinations that work with each. Sorry, I don't have a link - downloaded it a year or two ago. It should yield to a search. I can also send you the PDF if you PM me your contact info.

I have a DM and recently sold a DMR, both with DIC. They use the same series of condenser prisms (K...) but mount the objective side prisms differently. A slider for the DM. A sort of wedge-shaped mount in the DMR that fits a carousel with lateral adjustment for each prism. The DM series definitely has a "D" slider and it mates perfectly with a 100x Plan Fluotar 1.30 na objective with a D marking.

You do have to be careful in that Leica made objectives at the same magnification that called for different objective-side prisms. For example, the 20x Plan Fluotar has both B and D versions. I believe the 63x had both D and E versions (mine is a 63x Plan Apo E).

The D1 prism available for the DMR is apparently a higher resolution version of the shear angle. I suspect it would work in many cases where a D is specified, but without such a dramatic 3D effect. My recollection of the DMR is that the D1 and K4 prism were very good for a 100x N plan (1.25na) and the D1 and K6 prism pretty good for the 100x Plan Fluotar (1.3na).

After failing to find one upper prism I wanted (an "E" slider for that 63x) after a year, I managed to find one of the wedge-mounted ones affordably priced. I carefully cut it down, and then mounted it on a thin slider of my own devising. It was nerve-wracking work, with failure lurking the closer and closer I got to the glass. This had the immediate advantage, once completed and working, of magically making the OEM one I wanted suddenly appear at a not-too-unreasonable price on Ebay.

Should you be handy, and you find a cheap D prism, it might be possible to go the other way and pull a D prism out of a slider and mount in on a wedge. A D1 will probably prove satisfactory, especially if resolution rather than contrast and relief is your priority.

Awesomealgae
Posts: 15
Joined: Tue Oct 06, 2020 10:25 am

Re: Leica DM questions

#4 Post by Awesomealgae » Wed May 12, 2021 4:08 pm

apochronaut wrote:
Wed May 12, 2021 12:21 pm
There is probably a manual on-line, that should give you some guidance or more than likely you can download one from Leica Microsystems.
Regarding the prism combinations. Perhaps a D2 for the 100X.
I have never encountered a 1.63 N.A. objective. Objectives of over 1.6 N.A. have been made going way back, possibly to the war years, exoerimentally. Kodak, patented at least one of very high N.A. , 1.6 or something like that but the problem becomes one of maintaining a homogeneous condition. Coverslip glass needs to be that high and the immersion medium needs to be something like methylene iodide plus a 1.63 N.A. light source. I had a methylene iodide immersion 50X Leitz objective once but no methylene iodide.
The highest N.A. objective that Leica makes or rather that I know of is a 100X 1.44 oil with a correction collar in the HCX series. I have seen 1.45 oil objectives from other makers and once a 1.52 N.A. condenser.
Wow the collective knowledge here is so awesome. My bad for not making My self clear. I meant I would like to upgrade to a 63 with an NA >1 and a 100 with an NA > 1.3. Apochronaut,I cannot overstate how often your posts have helped on countless topics me in the past Thanks!

PeteM
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Re: Leica DM questions

#5 Post by PeteM » Wed May 12, 2021 4:18 pm

Leica's 63x Plan Apo has a 1.3na and a larger working distance - so you might want to consider that as an option. Essentially the same resolution as a high-end 100x, but able to see a few more microns on a cover slip.

Awesomealgae
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Re: Leica DM questions

#6 Post by Awesomealgae » Wed May 12, 2021 7:45 pm

Pete your an absolute legend! So much information here, Thanks! I’m not 100% sold on this scope yet. I was hoping to take this chance to downsize from the Polyvar which I absolutely love but perhaps not.
PeteM wrote:
Wed May 12, 2021 1:09 pm
That will be a wonderful scope - congratulations.

There is a listing of Leica HC objectives online that lists the prism combinations that work with each. Sorry, I don't have a link - downloaded it a year or two ago. It should yield to a search. I can also send you the PDF if you PM me your contact info.
Is it this one? Yes please it if it isn’t. I ‘ve found a DMR manual, but i cant find an accessories and parts list of DMR vintage anywhere. Leica don’t seem keen on making this legacy info available.

https://www.mikroskop-center.de/media/ ... ves_EN.pdf
PeteM wrote:
Wed May 12, 2021 1:09 pm
I have a DM and recently sold a DMR, both with DIC. They use the same series of condenser prisms (K...) but mount the objective side prisms differently. A slider for the DM. A sort of wedge-shaped mount in the DMR that fits a carousel with lateral adjustment for each prism. The DM series definitely has a "D" slider and it mates perfectly with a 100x Plan Fluotar 1.30 na objective with a D marking.
DMLB? Fab microscope! Used one for years at work, would have one in a heartbeat. Not sure i can find one and outfit it within budget.
PeteM wrote:
Wed May 12, 2021 1:09 pm
You do have to be careful in that Leica made objectives at the same magnification that called for different objective-side prisms. For example, the 20x Plan Fluotar has both B and D versions. I believe the 63x had both D and E versions (mine is a 63x Plan Apo E).
Now thats invaluable! i had read the data sheet as either / or! not that there were 2 varients of the objective.
PeteM wrote:
Wed May 12, 2021 1:09 pm
The D1 prism available for the DMR is apparently a higher resolution version of the shear angle. I suspect it would work in many cases where a D is specified, but without such a dramatic 3D effect. My recollection of the DMR is that the D1 and K4 prism were very good for a 100x N plan (1.25na) and the D1 and K6 prism pretty good for the 100x Plan Fluotar (1.3na).
Pretty sure i can source a K4, its the objective prisms which seem less common?
PeteM wrote:
Wed May 12, 2021 1:09 pm
After failing to find one upper prism I wanted (an "E" slider for that 63x) after a year, I managed to find one of the wedge-mounted ones affordably priced. I carefully cut it down, and then mounted it on a thin slider of my own devising. It was nerve-wracking work, with failure lurking the closer and closer I got to the glass. This had the immediate advantage, once completed and working, of magically making the OEM one I wanted suddenly appear at a not-too-unreasonable price on Ebay.
hahahahaha the way the universe sometimes :) Ive seen a few posts you’ve made on this topic with a Nikon perhaps? Nerve Wracking is understatement :) Have you seen many E prisms popping up? Or is this a bit like finding a 100x condenser prism for BHS. It’s a sticking point for me as its going to be essential for most the microscopy I do.

Did you have a DSLR mounted to the DMR any advice on this would be great ;)
Did you find a K2 prism by-the-way?

Thanks so much I’m sure we shall talk DMR again

PeteM
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Re: Leica DM questions

#7 Post by PeteM » Wed May 12, 2021 8:11 pm

A few answers:

- Yes, that's the listing of Leica objectives. There's another one out there that goes back to Delta optics days as well.

- Yes, what I've kept is a DMLB. The only thing I don't like about it is the two-speed fine focus "transmission" isn't quite perfect in either example I've had. The DMR was optically equivalent and with even more options available. It was just too massive to keep around. I've fixed up and either donated or sold at cost around 150 scopes. There are scores more here awaiting Micronauts or mentors, so space is an issue. If you have the space to keep a DMR at a dedicated bench, the Leica DIC optics are superb.

- There are both Delta and HC optics versions of the DMR. Many (perhaps most) objectives work well with both, and both are excellent, but you do need to have the proper heads and eyepieces for each version. If you don't buy one complete, take care in mixing and matching heads and eyepieces and to a lesser extent (in my experience) objectives.

- There's an E slider on Ebay now, somewhat reasonably priced and possibly available lower with an offer. I stopped looking at the wedge-mounted ones after finding one cheap and dissecting it to make a slider. And, yes, I finally found a K2 prism. Right now I've ended up with a spare DMLB, but only have prisms to support 20x, 40x, and 50x oil. It will need another K2 or something else with about the same shear angles to support 10x.

- The HC objectives are fairly well corrected (but not perfectly) so direct projection works reasonably well with a generic adapter to match field size to sensor size. I've tried both a 1" Sony sensor and a full-frame Nikon D750 and thought they were fine for viewing and casual documentation. A fussy photographer might want the proper relay optics.

- Better correction comes from using an old 35mm Leica HC camera adapter with a Leica photo relay lens. I gutted the shutter etc and plugged up the various holes. However, it crops some of the 25mm field available with a widefield head.

- Part of what I've been doing is buying, repairing, and forming impressions of various scopes from cheap to not so cheap to get an idea of the pros and cons - and pass what I've learned along to families at the low end and mentors at the high end. Sort of got sidetracked with a fascination for DIC. Some living things have incredibly sharp vision, or see into the UV or infrared. Seems we humans are lucky to have something like DIC to add to that.

Awesomealgae
Posts: 15
Joined: Tue Oct 06, 2020 10:25 am

Re: Leica DM questions

#8 Post by Awesomealgae » Thu May 13, 2021 11:18 pm

Ahhhh Pete, that's a fantastic initiative. I used to run the life-sciences lab at a university. Outreach is SO important. I regurally take my orthoplan into schools to show & teach kids about the micro-world.
I am that fussy ;) so I’ll start hunting for a 35mm HC camera adapter if this is the optimal solution.

DIC vision, what a wonderful way of looking at it.

wabutter
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Re: Leica DM questions

#9 Post by wabutter » Mon May 17, 2021 4:11 am

Awesomealgae,
The DMR certainly offers excellent DIC, but you will ultimately be disappointed when compared to a Polyvar. There really isn’t any better DIC than what was offered on the Polyvar. As a point of reference, the D vs D1 prism represent a difference in shear angle the changes the resolution and contrast levels. They both will work, however, the performance benefits are very much dependent on the specimen.

Awesomealgae
Posts: 15
Joined: Tue Oct 06, 2020 10:25 am

Re: Leica DM questions

#10 Post by Awesomealgae » Sat May 22, 2021 10:03 am

Hey Wabutter thanks for the D prism Info, thats very helpful!

Re the Polyvar I have to agree, it produces an extraordinary image. I’ve used a few Leica and Zeiss scopes and compared to the Poly, I would say they have different qualities rather than being better or worse. Although I attribute this to the objective as much as the DIC equipment. Ultimately I would like a platform that has a wider-range of objectives better suited to specific applications. I doubt ill part company with the polyvar, and I'd love to find an original rotatary slot poleriser and fluorescence module for it.

wabutter
Posts: 178
Joined: Thu May 09, 2019 12:27 am

Re: Leica DM questions

#11 Post by wabutter » Mon May 31, 2021 12:11 am

Which parts of the Fluorescence system for the Polyvar are you looking for? HBO 200 illuminator? Filter cubes?

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