Awakening a Leitz SM microscope

[Tonikon]

Hello to all forum friends,

Some years ago, I bought a second-hand Leitz SM microscope (black enamel series) paired with Apo objectives, periplan eyepieces, Berek condenser and trinocular head. I bought it because it is a very fascinating tool (and because it was a really good occasion...), but now I want to begin to use it. Infact, I have a photographic project about "life in a drop of water" and I have to photograph (in brightfield microscopy) a lot of living specimens.

I have already adapted a led illuminating system (a white Cree led hidden inside an old microscope illuminator) but I would like to ask you if my setup is really "competitive" with much more modern infinity microscopes in terms of image quality (risolution, optical aberrations...). Conversely, I'm not worried about speed and easiness of use. I have to spend a lot of time taking photos of a lot of specimen and I'd like to be sure to start with the right tool. I know that illuminating technics, pos-production, quality of sensors are determinant, but I'm afraid that that general optic quality of my tool should be the real limiting factor.

Moreover, it would be nice if someone can help me to add some new part (phase contrast condenser and objective, darkfield condenser...) to extend the operativity of my setup for living specimens.
In order to give more information about my setup, this is the objective list:

- Leitz SM with Trinocular head
- Berek condenser
- Periplans eyepieces (10x18 in the trinocular head)
- Leitz Apo 12.5/0.30 170/
- Leitz Apo 25/0.65 170/0.17
- Leitz Apo 40/0.95
- Leitz Apo Oel 90/1.32 170/0.17
- A fistful of Pl/NPl objectives and a Darkfield condenser (which I wasn't able to use correctly)

Forgive me for writing too much and asking too many questions and have mercy on my unsure English.

Thanks in advance,

Toni

[Macro_Cosmos]

A very nice piece of engineering.

if my setup is really "competitive" with much more modern infinity microscopes in terms of image quality (resolution, optical aberrations...)

Depends on your definition of competitive. It will for sure produce very nice images, however due to its age, modern objectives of the same level (apochromatic in this case) will have better correction, will have higher resolution and larger field number. Finite objectives aren't technically less sharp, it's just that the 4 big boys (Oly, Nikon, Zeiss, Leica) have all moved on to infinity systems because of the many advantages and have been refining their objectives since then.

Moreover, it would be nice if someone can help me to add some new part (phase contrast condenser and objective, darkfield condenser...) to extend the operativity of my setup for living specimens.

Here comes the limitations. For something this old, it's going to be incredibly difficult to source the correct original parts. Moreover, for phase contrast, you need specific objectives, not just an appropriate condenser. Your handful displayed here won't work, the objective needs an internal phase ring. Apochromatic phase contrast objectives are very very rare, so aim for fluorites/semiapochromats.

I did find some finite Leica objectives for phase contrast. In theory, you can get those and the specific finite phase contrast condenser. It's important to have the ability to centre the phase annuli. It's probably simpler to just move to a modern system, such as an Olympus BX line. I have the condenser up for sale, it's not hard to find. Someone else more educated should be able to provide more insight into old Leica parts.

For darkfield, it should work with all the dry objectives you've shown. The 100x won't do, you'd need a specific high NA oil darkfield condenser, the condenser must be oiled to the bottom of the slide (urgh, more clean up mess!!).

[Tonikon]

Hello Macro Cosmos,
and thanks for your reply: it looks really encouraging and very helpful.
I understand that probably the wisest thing is to start using this tool for brightfield photography, postponing the phase contrast method until I'll have more and more experience.
I have heard about oblique lighting and have seen very nice photos (of living subjects) taken with this lighting method. I remember reading that you can build something yourself, but I don't know where to start ...
I think I really have many and many things to learn in this area and I'm sure my questions are very naïve, but starting a new photographic adventure with the spirit of a child is perhaps one of the most beautiful emotions of maturity...
Toni

[Ichthyophthirius]

Hi Toni,

I know that illuminating technics, post-production, quality of sensors are determinant, but I'm afraid that that general optic quality of my tool should be the real limiting factor.

I'd like to assure you that this microscope will not be your limiting factor! As long as this microscope and the optics are in good order, they won't limit you for a long time. Not only is this a beautiful instument, the optics were among the best of their time and are still very useful. The Apo 12.5, 25 and 40 in particular give great images.

Far more important for you will be to practise microscopy and improve your sample preparation. Develop your skills and take them with you if and when you eventually move on to a modern microscope. I would recommend first using this microscope for at least a year, getting familiar with the different optics and illumination methods you have already available. Don't spend too much money buying new parts for the Leitz SM for now, as they might not be compatible with more modern microscopes.

You can find more information about the black Leitz microscopes here:
http://www.microscopy-uk.org.uk/mag/img ... es7rev.pdf
http://microscope.database.free.fr/Welcome.html

Sidenotes:
- the darkfield condenser will require oil (or glycerol) immersion http://microscope.database.free.fr/Acce ... oscopy.pdf
- there is an (expensive) Heine phase contrast system available for the cylindrical condenser fitting (again, I don't recommend it right now as it is very expensive) http://microscope.database.free.fr/Acce ... denser.pdf
- you can mix 37 mm and 45 mm parfocal Leitz objectives on the same nosepiece by using the PLEZY parfocal adapter ring
- the photo eyepiece Periplan 10x/18 (tube length: 160 mm) doesn't fit the trinocular tube adapter you have (designed for 170 mm) - the trinocular tube length is 8 mm too long in your setup (just in case you're wondering why the images in binocular and trinocular are not parfocal)

Regards, Ichty

[Pau]

Hi Tonikon, welcome aboard!

(Ichty was writing at the same time, but he's faster )

This is a very nice old microscope with top optics for its time.
But it is about 65-70yrs old and, as you can understand, techniques have evolved quite a lot (just compare a 1955 car with a today one... they do basically the same but they are pretty different, the old one could be more beautiful but the newer one is more efficient and safe, for example)

Resolution can be the same if NA of the objective is the same and all is alright (condenser setup, condition of the optics, illumination...)

As Macrocosmos says, it can be capable of taking quality pictures but can't be at the same level of today research instruments.

Anyway it still would be far superior to today basic microscopes. It also would be an excellent training instrument.
What I don't like of this specific model is the focusing mechanism: a single knob acting both macro and micrometric movements alternatively.

Also take a look at your photoeyepiece: this one is meant for 160 corrected microscopes, the one for 170 corrected one like yours has a thinner wide part, some info here: https://www.photomacrography.net/forum/ ... 75#p207575

And on how to couple a camera: https://www.photomacrography.net/forum/ ... =8&t=15607

and a Darkfield condenser (which I wasn't able to use correctly)

Could you describe and post close up images of the condenser? Likely we can help you.
Dark field is a very good illumination method for pond life
For transparent unstained subjects bright field is often deceiving, phase contrast and DIC are often the best methods but they require dedicated expensive equipment. Oblique illumination, cross polarization in some cases and of course dark field are very useful

[Tonikon]

Hi Ichty and thank you very much for your precious advices.
I have found very useful your links and now I have a lot of informations to metabolize.
This week I have tried to take some pics of a modest collection of prepared slides (they seem very kids-oriented...) and in order to connect the camera to the microscope, I have done a sort of adapter composed by four parts: a mechanical adapter to put the eyepiece on the trinocular head, an old Periplan GF10x (not the newer one, 10x18), an inverted Schneider Xenoplan 28mm f/2.0 (usually closed to f/2. and an adapter to m4/3 camera. The results seems adequate, but I have not enough experience to compare my results. For sure, I have not vignetting and images seem sharp corner to corner.
I share with you my first results, just to judge the general quality of my initial attempts.

[Ichthyophthirius]

To me, the images look great. You clearly have an 'eye' for photography (I also like your photos of the microscopy equipment).

You could move on making your own slides (pond life; diatoms; plant sections etc. are interesting) or experiment with different contrast methods (as mentioned above) or both.

[Tonikon]

Hi Pau and thanks for the nice welcome. I'm starting to be proud of my new old Leitz SM microscope ! However, I don't like the focusing system either ... quite impractical.
I share with you some picture of my condenser ... I think it is called "Berek condenser" and somewhere I read that it was used to obtain the Köhler illumination when there is no field diaphragm on the illuminator. I can not understand what is really the Köhler illumination and if it really has so many benefits. I actually adjust the height and the aperture of the condenser checking the "real time" appearance on the camera's LCD (a Pana G80), but I don't really think it's the best system. I still have so much to learn and this is the right place where...

[Scarodactyl]

Well done! What format camera are you using? 28mm is a shorter FL than is usually ideal for larger sensors (usually about 40mm for aps-c) but your results speak for themselves.

[Tonikon]

Hi Scarodactyl,
I'm using a m4/3 camera and the Xenoplan 28mm f/2 (an industrial C-mount lens) in mounted in inverted position. I have tried several lens/eyepiece combinations, without any precise competence and finally I have found that this combination gives sharpness across all frame, lackness of chromatic aberrations and no vignetting.
Toni

[Pau]

I was referring to the dark field condenser, I suspected that it was an oil immersion condenser like Ichty clearly stated. It won't work at all without oil between the top condenser lens and the slide. If it is 1.2 -1.4 model this means that it will work with objectives with NA smaller than 1.2 (although likely the illuminated field will be too small for 10X objectives)

The key for Köhler illumination is to focus the light source (in your case the LED die) at the back focal plane (and so having it perfectly defocused and uniform at the specimen plane).
-Focus the specimen in a transparent enough slide and remove one eyepiece; looking through the tube you can focus the light source with the condenser height knob.
Having a base field diaphragm is very convenient but not mandatory. I never used a Berek but you have the instructions at the "black enamel" article, pg. 20 Its lower diaphragm seems to be acting as field aperture.
Looking at your pictures I would not be surprised that you already are getting Köhler or close to it.

About your camera adaptation, it seems very nice and compact, could you further explain it a bit?
- Is the Xenoplan lens focused to infinite?
- Is there a Periplan eyepiece between the Xenoplan lens and the objective?
- Parfocality: Is the camera image parfocal with the viewing eyepieces? Is this maintained (with just a bit of refocusing) when you change objectives?
It seems a custom made adaptation, how did you make it?

[Tonikon]

Hi Pau,
in the next days (especially if it'll rain :-) I will try to "socialize" with the Berek condenser ... your directions and your links will help me a lot and the tool seemb to be very promising.
I built the adapter starting from a piece (which seems custom made) that allows you to insert an eyepiece on the trinocular output. Then I built myself the rest, adapting a Schneider Xenoplan 28mm f / 2.0 (a c-mount industrial lens) mounted in inverted position (through a cannibalized 30.5mm-49mm adapter) to the Periplan GF10x. A c-mount/m43 ring adapter has completed the work! It seems to work very well and compared to all other attempts it is by far the sharpest ... moreover, it is almost parfocal ... really a good fortune to be a piece from "eyeballing it"...

[Macro_Cosmos]

The brightfield images look nice and clean. I like it!

Forum member Saul sells various inserts on his ebay store, they are designed to be inserted into the condenser's rear opening. It's fun to use and smartly crafted, utilising magnets. Various darkfield rings, Rheinberg Illumination, oblique lighting inserts are offered. I started with brightfield earlier this year, my images... weren't that great! Practice is key.

I think it should be possible to DIY a phase contrast setup through 3D printed inserts that goes below the condenser. I do see two knobs, which allows centring. Ideally you'd want to have the condenser centred and then the annulus, however, I believe the latter is more important for higher magnifications. That said, always centre both if you can. Phase contrast produces nice images and works incredibly well.

[Tonikon]

...just to close the loop...
today I have found some time to take a picture with my Leiz SM microscope.
It's my first living specimen...a rotifer (I suppose...) found in the water of a puddle in the garden.
I have used the Leitz 25/0.65 Apo with the Berek condenser. It is a brightfield photography.
Nothing special, but...
Thanks to everyone for their advices.
Ciao
Toni

[Scarodactyl]

Seems fairly special to me. They may be old optics but they're still fierce.