Home page of the microscope service parts, repair and spare parts online catalog - Sermik-Oplatek Mikroskopservice Dresden f.n.n.Z

Description of this part for the microscope.

5 mm or others if you put a thickening ring on it.
The upper lens for strong magnifications can be unscrewed and then we get a condenser for objectives with low magnification and low numerical aperture.
I can't (or it is not possible) unscrew the lower part with the diaphragm separately.

Description of this part for the microscope.

numerical aperture.

Description of this part for the microscope.

Description of this part for the microscope.

microscope.

Description of this part for the microscope.

Description of this part for the microscope.

lens: yes
- Iris diaphragm: yes
- Type: Brightfield condenser for transmitted light

If you're not looking for this entire part, ask if I have separate components for sale, such as a screw-on ring or lenses.

Description of this part for the microscope.

10x, 40x, and 100x

This phase contrast condenser can be used with microscopes from virtually any manufacturer as long as they have a 39.5 mm condenser mounting diameter (PZO, Zeiss, Will Wetzlar, and dozens of others).
This high-quality phase contrast condenser was manufactured in Japan before the company was acquired by the Chinese company Motic.

Description of this part for the microscope.

Condenser holder
- Oblique light module with iris diaphragm and diaphragm lateral adjustment mechanism
- Condenser vertical adjustment knob, rack, and pinion

Vintage Dr. Adolf Schröder microscopes used optics from Otto Seibert, Wetzlar. These microscopes may be manufactured in Wetzlar, but are engraved with the name "Dr. Adolf Schröder, Kassel." Therefore, it is highly likely that parts are compatible between these two microscope manufacturers.

Oblique light allows observation in transmitted light and obtaining convex images of the colorless objects we are observing (DIC effect).

Description of this part for the microscope.

Interestingly, it has an unusual mounting diameter of approximately 38.5 mm.

Description of this part for the microscope.

condenser lens can be unscrewed, creating a condenser with a low numerical aperture, providing an ideal image when working with low-power objectives.

The dovetail on the bottom has a notch, most likely for a spring-loaded mounting screw, which should be located in the condenser holder.

Description of this part for the microscope.

Abbe
Iris diaphragm: yes
Filter holder: yes

The top lens can be unscrewed, providing a lower numerical aperture for working with low-power objectives.

Description of this part for the microscope.

Description of this part for the microscope.

wide-field lens
- mounting slot fitting the Vickers Patholux microscope

Unscrewing the upper lens reduces the numerical aperture of the condenser and allows optimal image quality when working with low-magnification objectives.

The lower wide-field lens can be inserted or removed from the optical path. Its presence in the optical path ensures illumination of the entire field of view when using very low-magnification objectives and prevents vignetting.

Description of this part for the microscope.

This insert fits condensers used in the following Lomo microscopes:
- Polam (all models)
- MIN-8
- MIK-1
- MIK-4

and most likely also in other microscopes that use similarly designed condensers. Note - to make sure that this insert fits your condenser, be sure to check the diameter of this element.

Mount diameter: 35 mm

The transmitted light condenser in these microscopes features:
- interchangeable upper lenses to obtain the required aperture
- a diaphragm located below the upper lens
- a slot for inserting a Pol filter insert (the insert may, but does not have to, include an additional iris diaphragm)

In some cases, this insert alone can be used without the condenser - the effect is similar to a condenser with a Pol filter of low N.A.
This element is often used by owners of microscopes from other manufacturers to convert their condenser into a polarisation condenser.

Since this element can be removed relatively easily, it is very often missing in microscopes from the secondary market.

IMPORTANT - this is not a separate microscope condenser. It is a component of the condenser, even though it is sometimes used as a substitute for a condenser.

Description of this part for the microscope.

condensers used in the following Lomo microscopes:
- Polam
- MIN-8
- MIK-1
- MIK-4

and most likely also in other microscopes that use similarly designed condensers. Note - to make sure that this insert fits your condenser, be sure to check the diameter of this element.

Mount diameter: 26 mm

The transmitted light condenser in these microscopes features:
- interchangeable upper lenses to obtain the required aperture
- a diaphragm located below the upper lens
- a slot for inserting a Pol filter insert (the insert may, but does not have to, include an additional iris diaphragm)

Note - this is the version without an iris diaphragm.

In some cases, this insert alone can be used without the condenser - the effect is similar to a condenser with a Pol filter of low N.A.
This element is often used by owners of microscopes from other manufacturers to convert their condenser into a polarisation condenser.

Since this element can be removed relatively easily, it is very often missing in microscopes from the secondary market.

IMPORTANT - this is not a separate microscope condenser. It is a component of the condenser, even though it is sometimes used as a substitute for a condenser.

Description of this part for the microscope.

Basic data:
- Element: microscope condenser
- Manufacturer: Meopta
- Manufacturer part number: 573 08 (57308)
- Numerical aperture: 1.0
- Design: condenser with a double-lens optical system
- Mounting diameter: 37 mm (exactly according to the manufacturer catalog 36.8 mm)
- Iris diaphragm: YES

Note - although the manufacturer describes it as "for polarizing microscopes" - this is NOT a polarizing condenser, i.e. it does not contain a polarizer - neither fixed nor rotatable.

This condenser fits any Meopta microscope as well as microscopes from other manufacturers (e.g. Lomo, Olympus, Carl Zeiss Jena and many others) with a condenser holder diameter of 37 mm.

Description of this part for the microscope.

Model: Lomo INF
Mount diameter: 35 mm

This insert fits condensers used in the following Lomo microscopes:
- MIK-1
- MIK-4
- Polam (all models)
- MIN-8

and most likely also in other microscopes that use similarly designed condensers. Note - to make sure that this insert fits your condenser, be sure to check the diameter of this element.

The transmitted light condenser in these microscopes features:
- interchangeable upper lenses to obtain the required aperture
- a diaphragm located below the upper lens
- a slot for inserting a IR filter insert (the insert may, but does not have to, include an additional iris diaphragm)

In some cases, this insert alone can be used without the condenser - the effect is similar to a condenser with a IR filter of low N.A.
This element is often used by owners of microscopes from other manufacturers to convert their condenser into a infrared condenser.

Since this element can be removed relatively easily, it is very often missing in microscopes from the secondary market.

IMPORTANT - this is not a separate microscope condenser. It is a component of the condenser, even though it is sometimes used as a substitute for a condenser.

Description of this part for the microscope.

where the letter "H" corresponds to the Latin "N". This means that the model name written in the Latin alphabet is KON-3, where "KON" is simply an abbreviation of the word condenser.

Basic data:
- Element: Abbe microscope condenser
- Manufacturer: Lomo
- Manufacturer designation: KOH-3
- Numerical aperture: 1.2
- Numerical aperture with top lens removed: 0.3
- Mounting diameter: 37 mm
- Iris diaphragm: YES
- Wide-field lens: YES, with the possibility of moving it into / out of the light path
- filter holder: YES

This condenser also fits microscopes from other manufacturers (e.g. Meopta, Olympus, Carl Zeiss Jena and many others) with a 37 mm condenser mount.

Important: Although the mounting diameter of the KOH-3 condenser is 37 mm, the top lens slightly protrudes beyond the condenser body. For this reason, in some cases installation requires the following steps:
- unscrew the top lens
- install the condenser in the holder
- screw the top lens back in

Note: If you use this condenser with a microscope from a manufacturer other than Lomo, please note that:
- the filter holder is designed for filters with a diameter of 33 mm
- while most manufacturers use the 32 mm standard diameter
As a result, 32 mm filters cannot be used in the KOH-3 condenser without modification - they simply fall out because the holder diameter is too large.

Description of this part for the microscope.

polarized transmitted light with the possibility of use as a brightfield condenser
Mounting: the condenser is permanently integrated with a dovetail mount
Top lens: flip-out system allowing the upper lens to be moved into or out of the optical path to change the numerical aperture
Iris diaphragm: yes
Diffuser: yes, with the possibility of moving it into or out of the optical path
Polarizer: yes, rotatable, with the possibility of moving it into or out of the optical path

This condenser fits the following Carl Zeiss Jena microscope models:
- Polmi-A
- Nf
- Ng
- Nu / Nu2

Note: despite the visual similarity of the mounting interface, this condenser does NOT fit the Carl Zeiss Jena Lu microscope.

Important: the condenser is permanently integrated with the dovetail mount and cannot be used with other microscopes without significant modifications.

Description of this part for the microscope.

inserted.

This is an element for repair of a microscope condenser by Carl Zeiss Jena, model Abbe 1.2.
Please note that this is an element (component) for a microscope part (condenser), not for a specific microscope model.

The handle in this ring breaks very frequently, and then the iris diaphragm cannot be opened or closed and the condenser loses its functionality. In such a case, instead of replacing the entire condenser, it is enough to replace only this element - that is, to repair the condenser (recommendation: always repair - never throw away).

Note - over the years Carl Zeiss Jena produced the Abbe 1.2 condenser in different versions, and this ring is available in at least two variants:
- ring with a thickness of 2.5 mm and a handle width of 6 mm
- ring with a thickness of 2 mm and a handle width of 3.5 mm

Here I present and offer a ring with a thickness of 2.5 mm and a handle width of 6 mm. Be sure to check whether this is exactly the ring you need.

Description of this part for the microscope.

are inserted.

This is an element for repair of a microscope condenser by Carl Zeiss Jena, model Abbe 1.2.
Please note that this is an element (component) for a microscope part (condenser), not for a specific microscope model.

The handle in this ring breaks very frequently, and then the iris diaphragm cannot be opened or closed and the condenser loses its functionality. In such a case, instead of replacing the entire condenser, it is enough to replace only this element - that is, to repair the condenser (recommendation: always repair - never throw away).

Note - over the years Carl Zeiss Jena produced the Abbe 1.2 condenser in different versions, and this ring is available in at least two variants:
- ring with a thickness of 2.5 mm and a handle width of 6 mm
- ring with a thickness of 2 mm and a handle width of 3.5 mm

Here I present and offer a ring with a thickness of 2 mm and a handle width of 3,5 mm. Be sure to check whether this is exactly the ring you need.

Description of this part for the microscope.

repair or upgrade of a microscope condenser by Carl Zeiss Jena, model Abbe 1.2.
Please note that this is an element (component) for a microscope part (condenser), not for a specific microscope model.

The Carl Zeiss Jena Abbe 1.2 condenser is available in the following versions:
- with a wide-field lens mounted at the bottom of the condenser, below the filter holder
- with a filter holder only, without a wide-field lens

With this lens, you can upgrade your condenser if it is not equipped with one.

Description of this part for the microscope.

model Abbe 1.2.
Please note that this is an element (a subcomponent) for a microscope part (the condenser) and not for a specific microscope model.

Description of this part for the microscope.

element (component) for a microscope part (condenser), not for a specific microscope model.

Description of this part for the microscope.

has a 20 mm thread.

Element: upper lens of a microscope condenser
Manufacturer: Leitz Wetzlar (Leica)
Model: 0,90 As
Thread diameter: 20 mm
Immersion: no - this is a dry upper lens

Description of this part for the microscope.

thread

Fits condensers:
- PZO KPI-2 (Pluta / Nomarski DIC)
- PZO K4Ph (phase contrast Ph, PhA, PhS, A)
- PZO K3Ph (phase contrast Ph, PhA, PhS, A)
- PZO K3Ph1 (phase contrast Ph, PhA, PhS, A)
- PZO KFL (phase contrast / darkfield for fluorescence)
- PZO KFF
- PZO K3Phz (variable phase contrast Phz)

This upper lens allows conversion of the mounting standard from PZO 39.5 mm to the 37 mm standard and the use of PZO condensers on many other microscopes, e.g. Olympus BH / CH-2 or Lomo MBB

This microscope element can solve the following issues:
- How to mount PZO DIC on a Lomo microscope?
- Can I install a PZO DIC KPI2 condenser on an Olympus CH-2 microscope?
- Can I use PZO phase contrast on my non-PZO microscope?
- Does PZO phase contrast or DIC work on a microscope with a 37 mm condenser mount?

Description of this part for the microscope.

yes

This condenser fits microscopes from many manufacturers (e.g. Steindorff Berlin, Zeiss, Carl Zeiss Jena, Leitz, Kremp Wetzlar, Will Wetzlar and many others) with a condenser holder diameter of 39.5 mm.

Description of this part for the microscope.

40
Mounting diameter: 39.5 mm
Iris diaphragm: yes
Filter holder: yes, for round filters with 32 mm diameter
Removable top lens: yes

This is a very rarely encountered condenser designed for use with high numerical aperture objectives (e.g. Nikon Plan Apo or Leitz PL-Fluotar Oel Fluoreszenz).

This condenser fits microscopes from many manufacturers (e.g. PZO, Zeiss, Carl Zeiss Jena, Leitz, Kremp Wetzlar, Will Wetzlar and many others) with a condenser holder diameter of 39.5 mm.

Description of this part for the microscope.

35 mm
Removable upper lens: yes
Iris diaphragm: yes
Filter holder: yes, for round filters with 32 mm diameter

IMPORTANT - there are many microscope models sold under the designation XSB-01. Please make sure to read the description of this microscope available here: https://www.microscopeparts.eu/microscope/311

Description of this part for the microscope.

condenser fits microscopes from many manufacturers (e.g. Lomo, Carl Zeiss Jena, Olympus and many others) with a condenser holder diameter of 37 mm.

Description of this part for the microscope.

special diaphragms was supplied. The set included phase contrast diaphragms and dark field diaphragms.

Note - I am showing and offering here one single diaphragm in holder - exactly the one visible in the photos. This is a phase contrast diaphragm (phase annulus). The complete set for the Lomo Polam microscope contains 5 diaphragms.

Important note:
Such diaphragms in a special holder, supplied as a set of five diaphragms, were an accessory for the Lomo Polam polarizing microscope. These diaphragms are mounted onto the polarizing microscope condenser in order to combine these observation techniques and obtain a phase image in polarized light. Please note that the same condensers can also be used in Lomo MIN series polarizing microscopes (for example Lomo MIN-6 or Lomo MIN-8 models) and in Lomo MIK series infrared microscopes (for example Lomo MIK-4). This means that there is nothing preventing the use of these phase annuli in those microscopes as well.

The newest version of the Lomo Polam microscope, namely the Lomo Polam LMPR model, no longer requires this accessory. The Lomo Polam LMPR already has a special polarizing phase contrast disc condenser (somewhat similar to the Lomo KF-4 condenser).

In the last photo in the gallery you can see a page from the Lomo Polam microscope manual where this element is shown. In the manual it is shown in figure number 6, element number 65.
The complete instruction manual for the Lomo Polam microscope is available here: https://www.facebook.com/groups/102512763506243/?multi_permalinks=1858054457952056

Description of this part for the microscope.

special diaphragms was supplied. The set included phase contrast diaphragms and dark field diaphragms.

Note - I am showing and offering here one single diaphragm in holder - exactly the one visible in the photos. This is a phase contrast diaphragm (phase annulus). The complete set for the Lomo Polam microscope contains 5 diaphragms.

Important note:
Such diaphragms in a special holder, supplied as a set of five diaphragms, were an accessory for the Lomo Polam polarizing microscope. These diaphragms are mounted onto the polarizing microscope condenser in order to combine these observation techniques and obtain a phase image in polarized light. Please note that the same condensers can also be used in Lomo MIN series polarizing microscopes (for example Lomo MIN-6 or Lomo MIN-8 models) and in Lomo MIK series infrared microscopes (for example Lomo MIK-4). This means that there is nothing preventing the use of these phase annuli in those microscopes as well.

The newest version of the Lomo Polam microscope, namely the Lomo Polam LMPR model, no longer requires this accessory. The Lomo Polam LMPR already has a special polarizing phase contrast disc condenser (somewhat similar to the Lomo KF-4 condenser).

In the last photo in the gallery you can see a page from the Lomo Polam microscope manual where this element is shown. In the manual it is shown in figure number 6, element number 65.
The complete instruction manual for the Lomo Polam microscope is available here: https://www.facebook.com/groups/102512763506243/?multi_permalinks=1858054457952056

Description of this part for the microscope.

special diaphragms was supplied. The set included phase contrast diaphragms and dark field diaphragms.

Note - I am showing and offering here one single diaphragm in holder - exactly the one visible in the photos. This is a special diaphragm with a small light aperture. The complete set for the Lomo Polam microscope contains 5 diaphragms.

Important note:
Such diaphragms in a special holder, supplied as a set of five diaphragms, were an accessory for the Lomo Polam polarizing microscope. These diaphragms are mounted onto the polarizing microscope condenser in order to combine these observation techniques and obtain a phase image in polarized light. Please note that the same condensers can also be used in Lomo MIN series polarizing microscopes (for example Lomo MIN-6 or Lomo MIN-8 models) and in Lomo MIK series infrared microscopes (for example Lomo MIK-4). This means that there is nothing preventing the use of these phase annuli in those microscopes as well.

The newest version of the Lomo Polam microscope, namely the Lomo Polam LMPR model, no longer requires this accessory. The Lomo Polam LMPR already has a special polarizing phase contrast disc condenser (somewhat similar to the Lomo KF-4 condenser).

In the last photo in the gallery you can see a page from the Lomo Polam microscope manual where this element is shown. In the manual it is shown in figure number 6, element number 65.
The complete instruction manual for the Lomo Polam microscope is available here: https://www.facebook.com/groups/102512763506243/?multi_permalinks=1858054457952056

Description of this part for the microscope.

microscope. It will most likely also fit other models from the Jenamed series (e.g. Jenamed Variant, Jenamed Fluorescence, Jenamed-2, Jenamed Hematology). Please note however that the Carl Zeiss Jena Jenamed Histology microscope is factory-equipped with a different type of condenser - the "flip-out" type.

To make sure whether this condenser will fit a specific Carl Zeiss Jena microscope from the Jenamed series, it is best to carefully check all dimensions based on the gallery photos or ask a question on a professional forum, e.g. https://www.mikroskopie-forum.de/

Mechanically, this condenser is mounted from the underside of the microscope stage - first it is screwed into the threaded opening in the stage and then secured with three screws. The upper lens can be unscrewed to obtain a condenser with a lower numerical aperture N.A. This condenser does not have an iris diaphragm installed because in Jenamed microscopes it is a separate element.

Replacing the condenser in a Carl Zeiss Jena Jenamed microscope may be necessary:
- when the upper lens becomes damaged, for example when it turns matte due to exposure to various chemical reagents
- when the upper lens becomes damaged due to rubbing. Surprisingly, this unusual type of damage is very common after several decades of microscope use.

In the last photo I indicate with an arrow exactly which element it is and where it is located in the microscope.

Description of this part for the microscope.

therefore cannot be used in:
- Jenamed Cytology
- Jenamed Variant
- Jenamed Hematology
- Jenamed Fluorescence
- Jenamed-2

Mechanically, this condenser is a "flip-out" design and is mounted in a metal frame together with a lever used to rotate it in order to obtain one of two operating modes: low or high numerical aperture N.A. This lever extends outside the microscope housing so that the user can operate it.

The complete module is mounted underneath the microscope stage by attaching the entire condenser assembly from below with four screws. This condenser does not contain an iris diaphragm because, in Jenamed microscopes, it is a separate component mounted beneath the condenser.

In the Carl Zeiss Jena Jenamed Histology microscope, this condenser is not used together with the wide-field lens that is installed beneath the condenser in other Jenamed models (part Si10 CZ 2711-1). In the Jenamed Histology model, a polarizer is installed in this position instead.

Replacement of the condenser in a Carl Zeiss Jena Jenamed Histology microscope may be necessary:
- when the upper lens becomes damaged, for example by becoming cloudy due to exposure to various chemical reagents
- when the upper lens is damaged by friction. Surprisingly, this unusual type of damage is very common after several decades of microscope use
- when the mechanical lens switching mechanism ("flip-out") becomes damaged

Metal cast or injection-moulded microscope parts manufactured by Carl Zeiss Jena carry their own part numbers. This condenser module bears number 2713 (full marking: Si10 CZ 2713).

In the last photograph, I indicate with an arrow exactly which component is being offered and where it is located within the microscope.

Description of this part for the microscope.

2 Fluorescence

It DOES NOT FIT Carl Zeiss Jena microscopes from the Jenamed series and therefore cannot be used in:
- Jenamed Cytology
- Jenamed Variant
- Jenamed Hematology
- Jenamed Histology

Mechanically, this condenser is mounted on the microscope stage support plate (stage support). The microscope stage is installed onto this support plate together with the condenser. The upper condenser lens can be unscrewed - after removing it, the condenser operates with a lower numerical aperture N.A.

This condenser does not contain an iris diaphragm because, in Jenamed microscopes, it is a separate component mounted beneath the condenser.

Replacement of the condenser in a Carl Zeiss Jena Jenamed-2 microscope may be necessary:
- when the upper lens becomes damaged, for example by becoming cloudy due to exposure to various chemical reagents (common in fluorescence applications)
- when the upper lens is damaged by friction. Surprisingly, this unusual type of damage is very common after several decades of microscope use

Metal cast or injection-moulded microscope parts manufactured by Carl Zeiss Jena carry their own part numbers. The microscope stage support plate on which the condenser is mounted bears number 3030 (full marking: Si10 CZ 3030).

In the last photograph, I indicate with an arrow exactly which component is being offered and where it is located within the microscope.

Description of this part for the microscope.

Amplival microscope
Number of lenses: 3
Numerical aperture N.A.: variable, from N.A. 0.16 to N.A. 1.4
Aperture diaphragm: yes, screwed on as a detachable module

The Carl Zeiss Jena pancratic condenser has three upper lenses:
- for working with low magnification objectives (usually up to 6.3x)
- Apl. 1.4 for working with high magnification objectives
- an oil immersion cardioid darkfield lens with N.A. = 1.05

Mechanically, this condenser is mounted on dovetail rails located on the microscope stage holder block.

Here are the mounting possibilities of the pancratic condenser to Carl Zeiss Jena microscopes:
- to Amplival, Docuval, Epival, Fluoval, Vertival microscopes, this condenser can be mounted directly
- to Ergaval, Nu, Nu 2, Nf microscopes, this condenser is mounted after unscrewing the aperture diaphragm from it
- to Jenaval, Jenapol, Jenalumar microscopes, this condenser can also be mounted, but it is installed together with the entire stage holder block from the Amplival microscope http://www.microscopy-uk.org.uk/mag/artfeb09/rs-jenalumar.html
- be careful, because the Lumipan microscope also features a pancratic condenser, but with a completely different mounting method

This condenser is often used as a "parts donor" for own DIY projects, for example:
- the Apl. 1.4 lens is often used to modify (upgrade) condensers with a lower numerical aperture N.A. in various microscopes
- the darkfield lens is very often used to build a standalone cardioid condenser
- the iris diaphragm has a very wide range of applications

On the last photo, an arrow indicates which element it is and where it is located in the microscope to clearly identify this part. Additionally, the attached video shows how the individual elements of this condenser move.

Description of this part for the microscope.

guide rails of the condenser holder. It is not a condenser mounted in a circular clamp, therefore it does not have a "diameter" parameter describing it.

This condenser was removed from a Leitz Wetzlar Dialux microscope (the first black model), but to the best of my knowledge it also fits other microscopes from the same era: Leitz Ortholux and Leitz Orthoplan. Important - it does not fit Leitz SM microscopes.

The upper flip-out lens provides the best image quality when working with objectives of high numerical aperture (N.A.). When the upper lens is flipped out, optimal illumination is achieved when using objectives with magnifications below 10x.

Description of this part for the microscope.

bright field
- dark field
- oblique illumination
- phase contrast

It can work with phase objectives of different magnifications and from different manufacturers (it is sufficient to manually adjust the ring diameter).

Basic parameters:
Manufacturer: Leitz Wetzlar
Model: Heine condenser
Mounting diameter: 39.5 mm
Numerical aperture N.A.: variable, up to 1.4

This Heine condenser was designed for microscopes with a condenser holder in the form of a circular clamp (e.g. Leitz SM microscopes). It is not a condenser that slides into mounting rails (as found, for example, in the Leitz Orthoplan microscope).

This condenser fits microscopes from many manufacturers (e.g. PZO, Steindorff Berlin, Zeiss, Carl Zeiss Jena, Leitz, Kremp Wetzlar, Will Wetzlar and many others) equipped with a 39.5 mm condenser holder.

Description of this part for the microscope.

The light source is inserted into this housing (the standard light source in this model is an 8V 20W bulb). The entire housing is covered with dense metal fins acting as a heat sink to dissipate heat. At the end of this housing there is a condenser lens collimating the light beam and a dovetail mount. This mount is used to attach the condenser to the next element of the illumination path, namely the holder with a slot for insertable sliders.

The model designation MMU-3 is written using the Latin alphabet. When written in Cyrillic, this designation looks like MMY-3, and people unfamiliar with the Cyrillic alphabet may therefore refer to this microscope model in that way.

Interestingly, the dovetail connection used here has a diameter of 41.5 mm, which is the standard mounting diameter for accessories (for example microscope heads and intermediate tubes) not only in Lomo microscopes, but also in Carl Zeiss Jena, Romanian IOR, Czechoslovak Meopta and many other microscopes. For this reason, this lamp housing is sometimes used as an EPI reflected light source in various Carl Zeiss Jena microscope modifications.

In the last photograph, on the scanned page from the instruction manual of the Lomo MMU-1 microscope, an arrow indicates which element is being offered and where it is located in the microscope, allowing this part to be identified unambiguously.

Description of this part for the microscope.

with the Lomo Polam polarizing microscope. The set included phase contrast diaphragms and dark field diaphragms. Here I present and offer a complete set.

Important note:
Such diaphragms in a special holder were supplied as a set of five diaphragms as an accessory for the Lomo Polam polarizing microscope. These diaphragms are mounted onto the polarizing microscope condenser to obtain a combination of these techniques and a phase image in polarized light. Please note that the same condensers can also be used in polarizing microscopes of the Lomo MIN series (for example Lomo MIN-6 or Lomo MIN-8 models) and in microscopes designed for infrared light work from the Lomo MIK series (for example Lomo MIK-4). This means that there is nothing preventing the use of these phase rings in those microscopes as well.

The latest version of the Lomo Polam microscope, namely the Lomo Polam LMPR model, no longer requires this accessory. The Lomo Polam LMPR already features a dedicated rotating polarizing phase condenser (somewhat similar to the Lomo KF-4 condenser).

The last photo in the gallery shows a page from the Lomo Polam microscope manual where this microscope part is presented. In the manual it is shown in figure number 6, item number 65.

If you have such a set but it is incomplete - browse this database - you will also find individual diaphragms offered separately - specifically to solve such situations.

Description of this part for the microscope.

method: below the microscope stage in the circular condenser holder
Mounting diameter: 37 mm
Condenser type: paraboloidal condenser
Iris diaphragm: yes (this is an uncommon feature in darkfield condensers)
Oil immersion: yes, the condenser was designed for cedarwood oil
Numerical aperture N.A.: not specified (however, since this is an oil-immersion condenser, its N.A. is greater than 1.0)
Additional information: the light refraction was calculated for a microscope slide glass thickness of 1.35 mm
Manufacturer's original name: condensatore per campo oscuro

The photographs in the gallery show that one retaining pin securing one iris diaphragm leaf is no longer in its original position. In order to preserve the historical condition of this vintage condenser, this detail has intentionally not been repaired. This minor defect does not affect the operation of the iris diaphragm, which can be clearly seen in the accompanying video.

The website "Museo di Storia della Psichiatria" (https://bbcc.regione.emilia-romagna.it), dedicated to the cultural heritage of the Italian region of Emilia-Romagna, provides a downloadable PDF museum record describing an identical condenser preserved in the museum's collection (https://bbcc.regione.emilia-romagna.it/samira/api/print/card/173420).

Description of this part for the microscope.

3
Numerical aperture N.A.: variable, from N.A. 0.16 to N.A. 1.4
Aperture diaphragm: no
Compatible microscope: Carl Zeiss Jena Lumipan

Mechanically, this condenser is mounted on a dovetail guide located beneath the microscope stage.

Several important notes:
- this pancratic condenser is compatible only with the Carl Zeiss Jena Lumipan microscope
- this condenser is not compatible with the Carl Zeiss Jena Nf or Carl Zeiss Jena Nu / Nu2 microscopes, even though the condenser used in those models is very similar
- this condenser does not include an iris diaphragm because the Carl Zeiss Jena Lumipan microscope has its aperture diaphragm located in the microscope base, directly below the condenser

In the last photograph, an arrow indicates which component is being described and where it is located in the microscope, making it easy to identify this part. In addition, the attached video shows how the individual components of this condenser move.

This condenser is often used as a "donor of parts" for DIY projects, for example:
- the Apl. 1.4 lens is often used to modify (upgrade) condensers with a lower numerical aperture N.A. in various microscopes
- the dark-field lens is very often used to build a custom cardioid condenser

Description of this part for the microscope.

meters:
Manufacturer: United Scope, owner of the OMAX microscope brand
Condenser type: oil dark field condenser
Numerical aperture N.A.: 1.25 - 1.36
Mounting diameter: 37 mm
Centering screws: yes, two

The standard 37 mm mounting diameter allows this condenser to be used with microscopes from many other manufacturers, for example Lomo Biolam and Olympus CH-2. After increasing the diameter to 39 mm (for example by using a collar printed on a 3D printer), this condenser also fits Zeiss West, PZO, Wild Wetzlar, Hund Wetzlar, Carl Zeiss Jena and many other microscopes.

Description of this part for the microscope.

Basic parameters:
Manufacturer: United Scope, owner of the AmScope microscope brand
Condenser type: oil dark field condenser
Numerical aperture N.A.: 1.25 - 1.36
Mounting diameter: 37 mm
Centering screws: yes, two

The standard 37 mm mounting diameter allows this condenser to be used with microscopes from many other manufacturers, for example Lomo Biolam and Olympus CH-2. After increasing the diameter to 39 mm (for example by using a collar printed on a 3D printer), this condenser also fits Zeiss West, PZO, Wild Wetzlar, Hund Wetzlar, Carl Zeiss Jena and many other microscopes.

Description of this part for the microscope.

Zeiss Jena
Model: Apl 1.4
Holder name according to the manufacturer's catalogue: Kondensor-Einhänger mo
Condenser name according to the manufacturer's catalogue: Aplanatischer Kondensor 1.4 mo / ms
Version: grey version from a Carl Zeiss Jena Ergaval microscope (as opposed to the black version used, for example, on Carl Zeiss Jena Nf microscopes)
Numerical aperture N.A.: 1.4
Aperture diaphragm: yes, mounted in the condenser holder
Wide-field lens: yes, swing-out type
Removable top lens: yes, unscrewable
Mounting diameter: the optical section (the condenser without the iris diaphragm) has a mounting diameter of 39.5 mm and can be unscrewed from the condenser holder

The complete assembly consists of the following components:
- upper Apl 1.4 lens
- removable condenser (mo / ms)
- iris diaphragm attached to the condenser holder
- condenser holder mo
- swing-out wide-field lens
- two centring screws

The last photograph in the gallery shows a page from the manufacturer's original catalogue. Arrows indicate both this exact condenser holder model and the matching condenser.

Mechanically, this condenser is mounted using a dovetail guide located beneath the microscope stage. On the Carl Zeiss Jena Ergaval this is a separate condenser mounting assembly, while on the Carl Zeiss Jena Amplival the dovetail is integrated into the microscope stage support assembly.

Description of this part for the microscope.

meters:
Manufacturer: Carl Zeiss Jena
Designation: Apl. 1,4
Name of the mount according to the manufacturer's catalogue: Kondensoreinhänger mfl 2, Bestellnummer 301080:021.26/0
Name of the condenser according to the manufacturer's catalogue: Aplanatischer Kondensor 1.4 mo / ms (applies only to the upper optical part)
Name of the condenser according to the manufacturer's catalogue: Kondensor hoher Lichtstärke mit Vorschaltsystem (applies to the entire module)
Version: grey colour with a black upper lens. Variant with a "dot" in the name after "Apl"
Numerical aperture N.A.: 1.4
Aperture diaphragm: yes, attached to the condenser mount
Wide-field lens: yes, it can be swung out of the optical path. This is the version with the large lens in a housing (see description below)
Removable upper lens: yes, it can be rotated
Mounting diameter: the optical part (condenser without diaphragm) has a mounting diameter of 39.5 mm and can be unscrewed from the condenser mount
Operating modes: the condenser can be used both as a dry condenser and as an immersion condenser

The entire part consists of the following elements:
- upper Apl. 1,4 lens
- screw-on/removable condenser (mo / ms)
- iris diaphragm screwed onto the condenser mount
- condenser mount model mfl 2
- swing-out wide-field lens
- two centering screws

This condenser is mainly used in Carl Zeiss Jena Fluoval / Fluoval-2 fluorescence microscopes. It is optimal for use with high-numerical-aperture apochromatic microscope objectives. For precisely this reason, users often install it on Carl Zeiss Jena Ergaval and Carl Zeiss Jena Amplival microscopes equipped with apochromatic objectives (Carl Zeiss Jena Apochromat).

It is worth mentioning again that this condenser can be used in two modes:
- without immersion oil on the upper lens of the condenser. In this case, it operates as a "dry condenser" and its numerical aperture N.A. is 0.9.
- with immersion oil on the upper lens of the condenser (i.e. underneath the microscope slide). In this case, it operates as an "immersion condenser" and its numerical aperture N.A. is 1.4, allowing a very bright image to be obtained - this is important in fluorescence microscopy or when using high-N.A. immersion objectives.

During production, this condenser was available in several versions:
- with a black upper lens, a dot in the model name (Apl. 1,4) and a wide-field module consisting of a single lens
- with a black upper lens, without a dot in the model name (Apl 1,4) and a single wide-field module consisting of several lenses (including one with a very small diameter)
- with a grey upper lens marked Apl 1,4mo2 and a single wide-field module consisting of several lenses (including one with a very small diameter)
- with a grey upper lens marked Apl 1,4mo2 and a wide-field module consisting of two independently swing-out lenses, each on its own mount

I have not found any information anywhere as to whether the above-mentioned versions differ in their operation. From experience, I know that they are used interchangeably - but I do not know whether any differences in operation can actually be noticed.

Mechanically, this condenser is mounted on dovetail rails located underneath the microscope stage. In Carl Zeiss Jena Ergaval microscopes, this is a separate condenser mounting block, whereas in Carl Zeiss Jena Fluoval / Amplival microscopes, the dovetail is located on the microscope stage holder block.

The manufacturer describes this condenser as follows: "High-intensity condenser with an auxiliary system for illuminating large fields while imaging the field diaphragm. [...] The condenser of the FLUOVAL 2 can be used as a dry and immersion condenser of the highest aperture to achieve the highest possible excitation intensity. It is equipped with a switchable wide-field system that illuminates the large fields of low-power objectives while providing a sharp image of the field diaphragm in the object plane."

Description of this part for the microscope.

meters:
Manufacturer: Carl Zeiss Jena
Designation: Apl. 1,4
Name of the mount according to the manufacturer's catalogue: Kondensoreinhänger mfl 2, Bestellnummer 301080:021.26/0
Name of the condenser according to the manufacturer's catalogue: Aplanatischer Kondensor 1.4 mo / ms (applies only to the upper optical part)
Name of the condenser according to the manufacturer's catalogue: Kondensor hoher Lichtstärke mit Vorschaltsystem (applies to the entire module)
Version: grey colour with a black upper lens. Variant without the "dot" in the name after "Apl"
Numerical aperture N.A.: 1.4
Aperture diaphragm: yes, attached to the condenser mount
Wide-field lens: yes, it can be swung out of the optical path. This is the version with the large lens in a housing (see description below)
Removable upper lens: yes, it can be rotated
Mounting diameter: the optical part (condenser without diaphragm) has a mounting diameter of 39.5 mm and can be unscrewed from the condenser mount
Operating modes: the condenser can be used both as a dry condenser and as an immersion condenser

The entire part consists of the following elements:
- upper Apl 1,4 lens
- screw-on/removable condenser (mo / ms)
- iris diaphragm screwed onto the condenser mount
- condenser mount model mfl 2
- swing-out wide-field lens
- two centering screws

This condenser is mainly used in Carl Zeiss Jena Fluoval / Fluoval-2 fluorescence microscopes. It is optimal for use with high-numerical-aperture apochromatic microscope objectives. For precisely this reason, users often install it on Carl Zeiss Jena Ergaval and Carl Zeiss Jena Amplival microscopes equipped with apochromatic objectives (Carl Zeiss Jena Apochromat).

It is worth mentioning again that this condenser can be used in two modes:
- without immersion oil on the upper lens of the condenser. In this case, it operates as a "dry condenser" and its numerical aperture N.A. is 0.9.
- with immersion oil on the upper lens of the condenser (i.e. underneath the microscope slide). In this case, it operates as an "immersion condenser" and its numerical aperture N.A. is 1.4, allowing a very bright image to be obtained - this is important in fluorescence microscopy or when using high-N.A. immersion objectives.

During production, this condenser was available in several versions:
- with a black upper lens, a dot in the model name (Apl. 1,4) and a wide-field module consisting of a single lens
- with a black upper lens, without a dot in the model name (Apl 1,4) and a single wide-field module consisting of several lenses (including one with a very small diameter)
- with a grey upper lens marked Apl 1,4mo2 and a single wide-field module consisting of several lenses (including one with a very small diameter)
- with a grey upper lens marked Apl 1,4mo2 and a wide-field module consisting of two independently swing-out lenses, each on its own mount

I have not found any information anywhere as to whether the above-mentioned versions differ in their operation. From experience, I know that they are used interchangeably - but I do not know whether any differences in operation can actually be noticed.

Mechanically, this condenser is mounted on dovetail rails located underneath the microscope stage. In Carl Zeiss Jena Ergaval microscopes, this is a separate condenser mounting block, whereas in Carl Zeiss Jena Fluoval / Amplival microscopes, the dovetail is located on the microscope stage holder block.

The manufacturer describes this condenser as follows: "High-intensity condenser with an auxiliary system for illuminating large fields while imaging the field diaphragm. [...] The condenser of the FLUOVAL 2 can be used as a dry and immersion condenser of the highest aperture to achieve the highest possible excitation intensity. It is equipped with a switchable wide-field system that illuminates the large fields of low-power objectives while providing a sharp image of the field diaphragm in the object plane."

Description of this part for the microscope.

without lenses used for? When working with low power objectives (roughly up to 10x - 12.5x), a better image is obtained
- either without any condenser
- or with an iris diaphragm only
- or with a special condenser of very low numerical aperture N.A.
This solution is very often used in inverted biological microscopes - and that is exactly how the condenser shown here was used.

If this were a complete condenser with optics (which it is not), the Zeiss microscope condenser P/N 465267 (also written as 46 52 67) could be fitted with N.A. 0.32 top lenses, with DIC or polarization top lenses N.A. Apl. 0.63, or with others, because the top lens is an interchangeable element screwed into the condenser housing.

The item shown here can be described as:
- a Zeiss condenser housing
- a Zeiss iris diaphragm in a housing
- also (although not correctly) a condenser with N.A. of about 0.20
However, since this is not a damaged item, it has the thread into which a condenser top lens can be screwed.

In Carl Zeiss microscopes of the Standard series (except the Standard Junior school model), the condenser is not mounted in a round holder. It has a ring-shaped dovetail that slides into the dovetail guide of the condenser carrier.

The last photo in the gallery shows the Carl Zeiss ICM 405 inverted microscope, with an arrow indicating exactly where this particular condenser was mounted.

The Zeiss 465267 condenser has a mount in the form of a dovetail ring. This mounting interface is used, among others (this is not a complete list), in the following microscope models:
- Zeiss Standard 14 / 16 / 18 / GFL
- Zeiss Standard WL / WL 89
- Zeiss Standard 20 / 25 / 25 ICS
- Zeiss Universal
- Zeiss Photomicroscope I / II / III RS
- Zeiss Ultraphot
- Zeiss IM 35 / ICM 405 inverted microscopes

The mounting ring of the condenser shown here has a diameter of 41.6 mm. The ring also has a factory-made conical notch that fits the locking pin fixing the position of the condenser. This pin is located in the condenser carrier.

Note on the mounting diameter: over nearly 50 years of production of microscopes of this series, the dovetail diameter was always about 42 mm - but it was not perfectly constant. Depending on the year of production, the material (plastic, aluminium, brass) and the type of condenser (classic Abbe or phase contrast turret condenser), it can range from slightly above 41 mm to almost 43 mm. Such a large tolerance results from the design of the condenser carrier: it has return springs, a locking pin and clamping / centering screws. Thanks to this, condensers with a mounting ring diameter of 41 to 43 mm can almost always be mounted stably.

Description of this part for the microscope.

Basic parameters of this phase annulus:
Position in the condenser: phase annulus to be fitted in the "40x" position of a turret condenser, to be paired with the phase ring in a 40x phase contrast objective
Construction: disc with a phase annulus in a mount
Material: glass, colourless polarising film and printed black circles
Diameter of the glass disc with the printed annulus: 14 mm
Disc mount: metal, with a notch for the spring-loaded ejector pin
Spring cushioning: no - the mount of the 40x phase annulus has no spring cushioning
Other names: phase disc, phase glass, phase ring
Intended for: PZO KS condenser
Compatibility: PZO K3Ph, K3Ph1, K4Ph and K3PhZ phase contrast condensers
Important note on appearance: the black dots and lines visible in the photo are not a surface defect - this is how PZO phase rings normally look
Note on the polarising film: two pieces of polarising film are glued onto the annulus. The vertical line running through the middle of the annulus is where these two films meet - it is neither a defect nor a crack, even though it looks like one

Over the years the polarising film used on these phase annuli very often came unstuck (delamination), which often - though not always - caused it to lose its properties and made stereoscopic contrast completely unusable. In such a case you can either:
- peel off the old film, clean the surface of the glass disc and glue on a new one, keeping the polarisation angle
- or replace the whole disc with one like the one offered here.

The specific feature of the PZO KS is that the ring of every disc is divided into two equal halves by two polarisers set perpendicular to each other. By rotating the analyser you extinguish one half of the ring and brighten the other - smoothly, without moving anything in the optical path. The specimen is then illuminated from one side.

And this is exactly how the disc from the KS condenser differs from the discs of the PZO K3Ph, K3Ph1, K4Ph and K3PhZ condensers. Mechanically it is the same insert, 14 mm in diameter, and it fits those condensers. The difference lies solely in the polarisation of the ring itself, described above. That is why a KS disc used in an ordinary phase condenser still gives correct phase contrast with no loss of quality, but once an analyser is placed in the optical path (for example under the head) it can produce interesting, unexpected effects.

For DIY enthusiasts looking for new, unusual visual effects in microscopy, an interesting option is to fit this polarising phase annulus into a different phase contrast condenser. You can then explore the unusual behaviour of various objectives in partially polarised light.
Here is an example: a Zernike-type phase contrast objective (PZO Ph with a green stripe) combined with the phase annulus from the PZO KS condenser gives an unusual, bluish background colour (https://www.facebook.com/photo?fbid=1262188377207557&set=a.462747092529893). And here you can see PZO microscope objectives for six types of phase contrast: https://www.facebook.com/MikroskopyPZO/photos/por%C3%B3wnanie-obiektyw%C3%B3w-pzo-20x-do-kontrastu-fazowego-pier%C5%9Bcienie-zielony-ph-kf-do/1259433520816376/.

The PZO KS condenser was fitted to PZO MB-30S microscopes and was an essential part of a special phase contrast method called "Stereoscopic Contrast" (KS). This condenser is characterised by carrying no markings at all - and that is how you recognise it.

Fastest way to recognise the PZO KS condenser:
PZO KS condenser: no serial number, no manufacturer name or logo, no model designation
Other PZO phase contrast condensers: at least a printed model designation (for example KFF, KFL, K3Ph, K3Ph1, K4Ph, K3PhZ, or KPI 2 in the case of the DIC condenser)

Description of this part for the microscope.

Basic parameters of this phase annulus:
Position in the condenser: phase annulus to be fitted in the "10x" position of a turret condenser, to be paired with the phase ring in a 10x phase contrast objective
Construction: disc with a phase annulus in a mount
Material: glass, colourless polarising film and printed black circles
Diameter of the glass disc with the printed annulus: 14 mm
Disc mount: metal, with a notch for the spring-loaded ejector pin
Spring cushioning: yes - inside the mount, underneath the glass with the phase annulus, there is a spring cushioning
Other names: phase disc, phase glass, phase ring
Intended for: PZO KS condenser
Compatibility: PZO K3Ph, K3Ph1, K4Ph and K3PhZ phase contrast condensers
Important note on appearance: the black dots and lines visible in the photo are not a surface defect - this is how PZO phase rings normally look
Note on the polarising film: two pieces of polarising film are glued onto the annulus. The vertical line running through the middle of the annulus is where these two films meet - it is neither a defect nor a crack, even though it looks like one

Over the years the polarising film used on these phase annuli very often came unstuck (delamination), which often - though not always - caused it to lose its properties and made stereoscopic contrast completely unusable. In such a case you can either:
- peel off the old film, clean the surface of the glass disc and glue on a new one, keeping the polarisation angle
- or replace the whole disc with one like the one offered here.

The specific feature of the PZO KS is that the ring of every disc is divided into two equal halves by two polarisers set perpendicular to each other. By rotating the analyser you extinguish one half of the ring and brighten the other - smoothly, without moving anything in the optical path. The specimen is then illuminated from one side.

And this is exactly how the disc from the KS condenser differs from the discs of the PZO K3Ph, K3Ph1, K4Ph and K3PhZ condensers. Mechanically it is the same insert, 14 mm in diameter, and it fits those condensers. The difference lies solely in the polarisation of the ring itself, described above. That is why a KS disc used in an ordinary phase condenser still gives correct phase contrast with no loss of quality, but once an analyser is placed in the optical path (for example under the head) it can produce interesting, unexpected effects.

For DIY enthusiasts looking for new, unusual visual effects in microscopy, an interesting option is to fit this polarising phase annulus into a different phase contrast condenser. You can then explore the unusual behaviour of various objectives in partially polarised light.
Here is an example: a Zernike-type phase contrast objective (PZO Ph with a green stripe) combined with the phase annulus from the PZO KS condenser gives an unusual, bluish background colour (https://www.facebook.com/photo?fbid=1262188377207557&set=a.462747092529893). And here you can see PZO microscope objectives for six types of phase contrast: https://www.facebook.com/MikroskopyPZO/photos/por%C3%B3wnanie-obiektyw%C3%B3w-pzo-20x-do-kontrastu-fazowego-pier%C5%9Bcienie-zielony-ph-kf-do/1259433520816376/.

The PZO KS condenser was fitted to PZO MB-30S microscopes and was an essential part of a special phase contrast method called "Stereoscopic Contrast" (KS). This condenser is characterised by carrying no markings at all - and that is how you recognise it.

Fastest way to recognise the PZO KS condenser:
PZO KS condenser: no serial number, no manufacturer name or logo, no model designation
Other PZO phase contrast condensers: at least a printed model designation (for example KFF, KFL, K3Ph, K3Ph1, K4Ph, K3PhZ, or KPI 2 in the case of the DIC condenser)

Description of this part for the microscope.

Basic parameters of this phase annulus:
Position in the condenser: phase annulus to be fitted in the "20x" position of a turret condenser, to be paired with the phase ring in a 20x phase contrast objective
Construction: disc with a phase annulus in a mount
Material: glass, colourless polarising film and printed black circles
Diameter of the glass disc with the printed annulus: 14 mm
Disc mount: metal, with a notch for the spring-loaded ejector pin
Spring cushioning: yes - inside the mount, underneath the glass with the phase annulus, there is a spring cushioning
Other names: phase disc, phase glass, phase ring
Intended for: PZO KS condenser
Compatibility: PZO K3Ph, K3Ph1, K4Ph and K3PhZ phase contrast condensers
Important note on appearance: the black dots and lines visible in the photo are not a surface defect - this is how PZO phase rings normally look
Note on the polarising film: two pieces of polarising film are glued onto the annulus. The vertical line running through the middle of the annulus is where these two films meet - it is neither a defect nor a crack, even though it looks like one

Over the years the polarising film used on these phase annuli very often came unstuck (delamination), which often - though not always - caused it to lose its properties and made stereoscopic contrast completely unusable. In such a case you can either:
- peel off the old film, clean the surface of the glass disc and glue on a new one, keeping the polarisation angle
- or replace the whole disc with one like the one offered here.

The specific feature of the PZO KS is that the ring of every disc is divided into two equal halves by two polarisers set perpendicular to each other. By rotating the analyser you extinguish one half of the ring and brighten the other - smoothly, without moving anything in the optical path. The specimen is then illuminated from one side.

And this is exactly how the disc from the KS condenser differs from the discs of the PZO K3Ph, K3Ph1, K4Ph and K3PhZ condensers. Mechanically it is the same insert, 14 mm in diameter, and it fits those condensers. The difference lies solely in the polarisation of the ring itself, described above. That is why a KS disc used in an ordinary phase condenser still gives correct phase contrast with no loss of quality, but once an analyser is placed in the optical path (for example under the head) it can produce interesting, unexpected effects.

For DIY enthusiasts looking for new, unusual visual effects in microscopy, an interesting option is to fit this polarising phase annulus into a different phase contrast condenser. You can then explore the unusual behaviour of various objectives in partially polarised light.
Here is an example: a Zernike-type phase contrast objective (PZO Ph with a green stripe) combined with the phase annulus from the PZO KS condenser gives an unusual, bluish background colour (https://www.facebook.com/photo?fbid=1262188377207557&set=a.462747092529893). And here you can see PZO microscope objectives for six types of phase contrast: https://www.facebook.com/MikroskopyPZO/photos/por%C3%B3wnanie-obiektyw%C3%B3w-pzo-20x-do-kontrastu-fazowego-pier%C5%9Bcienie-zielony-ph-kf-do/1259433520816376/.

The PZO KS condenser was fitted to PZO MB-30S microscopes and was an essential part of a special phase contrast method called "Stereoscopic Contrast" (KS). This condenser is characterised by carrying no markings at all - and that is how you recognise it.

Fastest way to recognise the PZO KS condenser:
PZO KS condenser: no serial number, no manufacturer name or logo, no model designation
Other PZO phase contrast condensers: at least a printed model designation (for example KFF, KFL, K3Ph, K3Ph1, K4Ph, K3PhZ, or KPI 2 in the case of the DIC condenser)

Description of this part for the microscope.

a low-power survey condenser with low numerical aperture and a main condenser with high aperture. Both sit on a common carrier at the same time, which lets you switch between them. What I am offering here is the condenser alone, so without the carrier.

Parameters of this condenser:
Manufacturer: Carl Zeiss Jena
Numerical aperture N.A.: 0.12
Correction: aplanatic
Mounting: the condenser screws into a dedicated carrier. The thread diameter is 36 mm.
Iris diaphragm: yes, the condenser has a ring that opens and closes the diaphragm
Removable top lens: no
Intended use: this condenser model was fitted in Carl Zeiss Jena Jenaval microscopes

This condenser can also be screwed into the carrier of Carl Zeiss Jena Jenalumar microscopes - it is the same carrier as in Jenaval microscopes. Note, however, that Jenalumar microscopes came with a 0.20 N.A. condenser as standard (you can see it here: https://www.microscopeparts.eu/part/00530).

A condenser with such a low numerical aperture is intended for observation with low magnification microscope objectives (1.25x / 3.2x / 6.3x, 10x at most).

Description of this part for the microscope.

a survey condenser with low numerical aperture and a main condenser with high aperture. Both sit on a common carrier at the same time, which lets you switch between them. What I am showing here is the main one, with the 0.9 aperture - the condenser alone, so without the carrier.

Parameters of this condenser:
Manufacturer: Carl Zeiss Jena
Numerical aperture N.A.: 0.9
Correction: achromatic-aplanatic (Achr. apl.)
Immersion: no. This is a dry condenser
Mounting: the condenser carrier holds a centrable threaded ring, and the condenser screws into that ring. The thread diameter is 38 mm.
Iris diaphragm: not on the condenser - the diaphragm sits in the carrier, below the condenser
Intended use: this condenser model was fitted in Carl Zeiss Jena Jenaval microscopes

How it mounts in the carrier:
- The condenser carrier holds a threaded ring, and the ring itself is centrable - two centring screws do that job (these ones: https://www.microscopeparts.eu/part/00535).
- The screws set the position of the ring, and the condenser simply screws into that ring.
- Further down, in the same carrier, sits the iris diaphragm for this main condenser. It is centrable as well and has its own screws for that.

This condenser can also be screwed into the carrier of Carl Zeiss Jena Jenalumar microscopes - it is the same carrier as in Jenaval microscopes. Note, however, that Jenalumar microscopes run the Apl. 0.9 condenser from the factory, that is the aplanatic version without achromatic correction.

The Achr. apl. 0.9 condenser is the working condenser of these microscopes - it covers the whole range of dry objectives, but with immersion objectives it works without making use of their full aperture.