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Description of this part for the microscope.

Hohlspiegelkondensor 10)
- Carl Zeiss Jena Apochromat 32x microscope objective

Model: Hohlspiegelkondensor 10
Color: Black
Internal thread: M19

Objective:
---------
Manufacturer: Carl Zeiss Jena
Model: Apochromat 32x 0.65 oo
Tube length: infinity
Magnification: 32x
Numerical aperture: 0.65
Cover glass: no
Type: EPI (reflected light)
Thread: M19

This element is used for EPI observations in reflected light in microscopes with a suitable EPI illuminator (Auflichtkondensor) installed, e.g. Carl Zeiss Jena NF or NU / NU-2 and with Vertival, Epival, Epignost, BK 70x50 microscopes - although they are also available in versions supporting other objectives).

Description of this part for the microscope.

Hohlspiegelkondensor 9)
- Carl Zeiss Jena Planachromat 4x microscope objective

Model: Hohlspiegelkondensor 9
Color: Black
Internal thread: M19

Objective:
---------
Manufacturer: Carl Zeiss Jena
Model: Planachromat K 4x/0,05 oo/0 oo/2
Tube length: infinity
Magnification: 4x
Numerical aperture: 0.05
Cover glass: no OR 2 mm
Type: EPI (reflected light)
Thread: M19
Info: this microscope objective can work in oo/0 mode or after unscrewing the upper lens in oo/2 mode (e.g. for a Petri dish or through a microscope slide)

Mirror objective slides / inserts are used for EPI observations in reflected light in microscopes with a suitable EPI illuminator (Auflichtkondensor) installed, e.g. Carl Zeiss Jena NF or NU / NU-2 and with Vertival, Epival, Epignost, BK 70x50 microscopes - although they are also available in versions supporting other objectives).

Description of this part for the microscope.

Hohlspiegelkondensor 12)
- Carl Zeiss Jena Planachromat 12,5x microscope objective

Model: Hohlspiegelkondensor 12
Color: Grey
Internal thread: M19

Objective:
---------
Manufacturer: Carl Zeiss Jena
Model: Planachromat 12,5x 0.25 oo/0
Tube length: infinity
Magnification: 12,5x
Numerical aperture: 0.25
Cover glass: no
Type: EPI (reflected light)
Thread: M19

This element is used for EPI observations in reflected light in microscopes with a suitable EPI illuminator (Auflichtkondensor) installed, e.g. Carl Zeiss Jena NF or NU / NU-2 and with Vertival, Epival, Epignost, BK 70x50 microscopes - although they are also available in versions supporting other objectives).

Description of this part for the microscope.

Hohlspiegelkondensor 12)
- Carl Zeiss Jena Planachromat 10x microscope objective

Model: Hohlspiegelkondensor 12
Color: Black
Internal thread: M19

Objective:
---------
Manufacturer: Carl Zeiss Jena
Model: Planachromat 10x 0.20 oo/-
Tube length: infinity
Magnification: 10x
Numerical aperture: 0.20
Cover glass: no
Type: EPI (reflected light)
Thread: M19

This element is used for EPI observations in reflected light in microscopes with a suitable EPI illuminator (Auflichtkondensor) installed, e.g. Carl Zeiss Jena NF or NU / NU-2 and with Vertival, Epival, Epignost, BK 70x50 microscopes - although they are also available in versions supporting other objectives).

Description of this part for the microscope.

Manufacturer: Lomo
Magnification: 20x
Model: 20 0.40 P
Numerical aperture: 0.40
Tube length: 160 mm
Focal length: 33 mm
Cover glass: yes, 0.17 mm
Thread: RMS + Pol adapter
Info: P = Polarization

This is an objective designed for transmitted light work with a cover glass.

The RMS thread objective is mounted on a dedicated slide-in adapter that allows it to be used in Lomo MIN series and Lomo Polam series microscopes. Of course, the objective can be unscrewed and another objective can be mounted in the adapter.

The objective itself, once removed from the adapter, is a standard objective that can be used in virtually any microscope with an RMS thread. It is a so-called "short objective" (focal length 33 mm). When a 12 mm adapter is added, the total length becomes 45 mm, allowing it to be used with newer microscopes from any manufacturer.

Lomo polarization objectives with RMS thread can be installed in an RMS-M27 adapter and then used in microscopes such as Lomo Biolam M, Lomo Biolam I, Lomo Lumam, or Lomo ML-2. I have also frequently seen such objectives used in Zeiss Axio series microscopes with M27 thread.

The Pol adapter also allows precise centering of the objective relative to the entire optical path - this requires tools (keys / tools).

Info: I have repeatedly seen information stating that this RMS-Pol adapter is compatible with Leitz Wetzlar polarization microscopes - however, I have not personally verified this.

In summary, this objective is dedicated to Lomo MIN-1, MIN-4, MIN-5, MIN-6, MIN-8, Lomo Polam R-113, Polam L-211, Polam L-213, Polam R-311, Polam LMPR microscopes - but it is practically compatible with any microscope from any manufacturer that supports 160 mm objectives.

Description of this part for the microscope.

Note - this model of microscope objective is very often used for macro photography and focus stacking. More information on this can be found at the end of this description.

Manufacturer: Lomo
Magnification: 9x
Model: PLANACHR 9x0.20 P
Numerical aperture: 0.20
Optical correction: planachromatic (flat field)
Tube length: 160 mm
Focal length: 33 mm
Cover glass: optional, can be used but is not required
Thread: RMS + Pol adapter
Info: P = Polarization

The RMS thread objective is mounted on a dedicated slide-in adapter that allows it to be used in Lomo MIN series and Lomo Polam series microscopes. Of course, the objective can be unscrewed and another objective can be mounted into the adapter.

The objective itself, once removed from the adapter, is a standard objective that can be used in virtually any microscope with an RMS thread. It is a so-called "short objective" (focal length 33 mm). When a 12 mm adapter is added, the total length becomes 45 mm, allowing it to be used with newer microscopes from any manufacturer.

Lomo polarization objectives with RMS thread can be installed in an RMS-M27 adapter and then used in microscopes such as Lomo Biolam M, Lomo Biolam I, Lomo Lumam, or Lomo ML-2. I have also frequently seen such objectives used in Zeiss Axio series microscopes with M27 thread.

The Pol adapter also allows precise centering of the objective relative to the entire optical path - this requires tools (keys / tools).

Info: I have repeatedly seen information stating that this RMS-Pol adapter is compatible with Leitz Wetzlar polarization microscopes - however, I have not personally verified this.

In summary, this objective is dedicated to Lomo MIN-1, MIN-4, MIN-5, MIN-6, MIN-8, Lomo Polam R-113, Polam L-211, Polam L-213, Polam R-311, Polam LMPR microscopes - but it is practically compatible with any microscope from any manufacturer that supports 160 mm objectives.

Additionally, this objective is very often used for macro photography even without a microscope. This objective does not require a cover glass and works in the "direct-projection" technique, meaning it can be connected directly to a camera without additional optics. This allows achieving a very high magnification scale and great depth of field across the entire image when using focus stacking. The fact that this is a polarization objective (i.e. stress-free optics without internal glass tensions) further improves image quality at high magnifications.

Description of this part for the microscope.

Note - this model of microscope objective is very often used for macro photography and focus stacking. More information on this can be found at the end of this description.

Manufacturer: Lomo
Magnification: 3,7x
Model: 3,7 0,11
Numerical aperture: 0.11
Tube length: 160 mm
Focal length: 33 mm
Cover glass: optional, can be used but is not required
Thread: RMS + Pol adapter
Info: P = Polarization

The RMS thread objective is mounted on a dedicated slide-in adapter that allows it to be used in Lomo MIN series and Lomo Polam series microscopes. Of course, the objective can be unscrewed and another objective can be mounted into the adapter.

The objective itself, once removed from the adapter, is a standard objective that can be used in virtually any microscope with an RMS thread. It is a so-called "short objective" (focal length 33 mm). When a 12 mm adapter is added, the total length becomes 45 mm, allowing it to be used with newer microscopes from any manufacturer.

Lomo polarization objectives with RMS thread can be installed in an RMS-M27 adapter and then used in microscopes such as Lomo Biolam M, Lomo Biolam I, Lomo Lumam, or Lomo ML-2. I have also frequently seen such objectives used in Zeiss Axio series microscopes with M27 thread.

The Pol adapter also allows precise centering of the objective relative to the entire optical path - this requires tools (keys / tools).

Info: I have repeatedly seen information stating that this RMS-Pol adapter is compatible with Leitz Wetzlar polarization microscopes - however, I have not personally verified this.

In summary, this objective is dedicated to Lomo MIN-1, MIN-4, MIN-5, MIN-6, MIN-8, Lomo Polam R-113, Polam L-211, Polam L-213, Polam R-311, Polam LMPR microscopes - but it is practically compatible with any microscope from any manufacturer that supports 160 mm objectives.

Additionally, this objective is very often used for macro photography even without a microscope. This objective does not require a cover glass and works in the "direct-projection" technique, meaning it can be connected directly to a camera without additional optics. This allows achieving a very high magnification scale and great depth of field across the entire image when using focus stacking. The fact that this is a polarization objective (i.e. stress-free optics without internal glass tensions) further improves image quality at high magnifications. Info: https://www.closeuphotography.com/lomo-3-7x-objective/2017/12/24/lomo-37x-011-microscope-objective

Description of this part for the microscope.

microscope objective
- Manufacturer: Carl Zeiss Jena
- Designation: Planachromat 25x/0,50 oo/0,17
- Magnification: 25x
- Numerical aperture N.A.: 0,50
- Optical correction: infinity-corrected tube length
- Optical correction class: planachromat
- Cover glass: yes, 0.17 mm
- Thread: M19

Some facts about Carl Zeiss Jena objectives with M19 thread (CZJ M19) and their compatibility with various microscopes from this manufacturer:
- these objectives are most commonly used for technical applications rather than biological applications, therefore most objectives available on the secondary market are intended for use without a cover glass (designation oo/0)
- CZJ M19 objectives intended for biological applications (designation oo/0,17) are most commonly used on Carl Zeiss Jena NU / NU2 microscopes
- in Carl Zeiss Jena Nf and Lumipan microscopes, CZJ M19 objectives are used together with an EPI illuminator
- CZJ M19 objectives can be used in Carl Zeiss Jena Polmi-A microscopes, but they provide a different magnification than the nominal value
- Carl Zeiss Jena Amplival / Amplival Pol / Amplival Interphako / Peraval microscopes feature interchangeable nosepieces, and a dedicated nosepiece for M19-thread objectives was also produced for these microscopes
- Carl Zeiss Jena Metaval and Neophot microscopes use newer versions of CZJ M19 objectives (with a coarse-knurled edge and shiny housing), although many users still experiment with older M19 objectives on these microscopes
- Carl Zeiss Jena Epignost and BK 70x50 microscopes were produced in various versions with completely different configurations - and some of them operate with CZJ M19 objectives
- Carl Zeiss Jena Vertival / Epival / Nf / BK 70x50 microscopes often allow the use of CZJ M19 objectives in EPI dark-field mode
- on the Carl Zeiss Jena Epityp-2 inverted metallurgical microscope, many users employ biological objectives designed for use with a cover glass, placing the microscope slide "upside down", with the cover glass facing downward toward the objective.

Description of this part for the microscope.

Carl Zeiss Jena
Engraving on the objective: Planachromat 25x/0,50 ∞/0
Magnification: 25x
Numerical aperture N.A.: 0,50
Free working distance: 3,1 mm
Tube length: infinity (more precisely: 250 mm)
Optical correction: planachromatic
Cover glass: no - this objective is intended for work without a cover glass
Immersion: no - this is a so-called dry objective
Phase contrast: no - this objective has no phase ring inside
Polarisation: no - this is not a polarising objective
Thread: M19
Plan compensating eyepieces: yes, required - this objective calls for eyepieces with additional correction (designated "PK" by Carl Zeiss Jena)
Direct projection and macro photography: no - this objective does not work in direct projection mode and is not suitable for macro photography by connecting the objective directly to a camera

This objective can be used as:
- an objective for work in reflected light (EPI), for biological as well as, among others, metallurgical or mineralogical applications
- an objective for work in transmitted light, among others with biological specimens or, for example, with mineralogical thin sections

A few facts about Carl Zeiss Jena objectives with M19 thread (CZJ M19) and their compatibility with various microscopes of this company:
- these objectives serve mostly technical applications and are intended for work without a cover glass (marking ∞/0)
- CZJ M19 objectives intended for biological applications (that is, marked ∞/0,17) are most often used on Carl Zeiss Jena NU / NU2 microscopes
- in Carl Zeiss Jena Nf and Lumipan microscopes, CZJ M19 objectives are used together with the EPI illuminator and can then work both in bright field and in dark field
- in Carl Zeiss Jena Polmi-A microscopes, CZJ M19 objectives can be used, but they give a magnification other than the nominal one
- Carl Zeiss Jena Amplival / Amplival Pol / Amplival Interphako / Peraval microscopes have an interchangeable nosepiece, and there is also a nosepiece intended for these microscopes that accepts objectives with M19 thread
- Carl Zeiss Jena Metaval microscopes use newer versions of CZJ M19 objectives (those with a coarsely knurled rim and a glossy barrel), yet many people experiment with older M19 objectives on these microscopes
- Carl Zeiss Jena Epignost and BK 70x50 microscopes were produced in various configurations - and some work with CZJ M19 objectives
- Carl Zeiss Jena Vertival / Epival / Nf / BK 70x50 microscopes often allow work with CZJ M19 objectives in EPI dark field mode
- on inverted metallographic Carl Zeiss Jena Epityp-2 / Neophot-21 microscopes, many people use biological objectives intended for work with a cover glass alongside metallurgical ones, and place the slide with the specimen on the stage "upside down", that is, with the cover glass facing downwards

Description of this part for the microscope.

21 microscope.

Basic parameters:
Manufacturer: Carl Zeiss Jena
Engraving on the objective: Planachromat 25x/0,50 ∞/0 Ph
Magnification: 25x
Numerical aperture N.A.: 0,50
Tube length: infinity (more precisely: 250 mm)
Optical correction: planachromatic
Cover glass: no - this objective is intended for work without a cover glass
Immersion: no - this is a so-called dry objective
Phase contrast: yes, a special phase contrast for work in reflected light
Polarisation: no - this is not a polarising objective
Thread: M19
Plan compensating eyepieces: yes, required - this objective needs eyepieces with additional correction (marked "PK" at Carl Zeiss Jena)
Direct projection and macro photography: no - this objective does not work in direct projection mode and is not suitable for macro photography with the objective attached directly to a camera

Phase contrast objectives for the Neophot microscopes have a phase ring built differently from the other Ph objectives made by Carl Zeiss Jena - instead of a continuous ring there is a three-segment pattern, somewhat reminiscent of a Wankel engine rotor. This is worth knowing, because it means that a phase contrast objective from a biological microscope will not replace this one in a Neophot, and the other way round.

The reason is a matter of design. In a metallurgical microscope the objective also acts as the condenser, so the illuminating light passes through the same pupil as the light forming the image. With a continuous ring the whole illumination would pass through the phase coating, which lets only part of the light through and reflects a fair amount of it - and those reflections would swamp the already faint phase contrast image. The solution turned out to be an odd number of segments: the image of the diaphragm formed after reflection off the specimen is rotated by 180 degrees, so with three segments it falls into the gaps between them. The illuminating light therefore enters beside the phase coating and returns through it. The solution is described in patent AT 295883 B.

The objective is offered together with its matching slider (Objektivwechselschlitten) with an M19 thread - and that is no coincidence. The position in which the phase sectors come to rest is decided by how far the objective screws into the thread, and every specimen stops slightly differently, which is why the factory selected objective and slider in pairs and wrote both numbers on the card in the case. Buying such a pair together avoids the whole problem - the objective already sits in relation to its slider exactly as it left the works.

Setting it up in the microscope needs neither a service technician nor a phase telescope - the Neophot has a built-in, swing-out Bertrand lens. The procedure is basically this: switch in the Bertrand lens, focus on the phase sectors and use the adjusting screws to bring the image of the sector diaphragm into coincidence with the image of the sectors in the objective; sometimes a slight rotation of the aperture diaphragm helps as well. Should the position of the glass in the sector diaphragm itself ever need correcting - it is held down by an ordinary threaded ring, so it can be turned. The whole thing resembles centring the phase rings in the condenser of a biological microscope.

Two more things are needed on the microscope side for work in phase contrast: the sector diaphragm (Sektorenblende), pushed in front of the open aperture diaphragm, and the auxiliary lens turret (Hilfslinsenrevolver) on the dovetail of the illuminator. The latter images the diaphragm exactly in the plane of the phase coating, which lies slightly differently in each objective - hence a separate auxiliary lens for every magnification. In bright field the objective of course works perfectly normally.

A note for the DIY-minded: an objective like this can be adapted for transmitted light, except that the diaphragm in the condenser is then set not opposite but in line with the segments of the objective, because there is no second pass through the pupil. Phase contrast should appear, but with stronger halo and a directional relief effect, since the gaps in the ring mean that part of the illumination azimuths is missing. On top of that comes the infinity design with no cover glass correction, so a tube lens will be needed. More of an experiment than a working solution - but doable in one evening.

The last photos in the gallery show:

* a photo of the original table indicating which serial numbers of the objective sliders are factory-paired with which serial numbers of the objectives
* two pages of errata to the instruction manual of the Carl Zeiss Jena Neophot 2 microscope.

The "compatibility" section lists, besides the Carl Zeiss Jena Neophot 21 microscope, those microscopes that this objective fits mechanically and optically. What result you get on them, however, can sometimes be a surprise.

Here (https://www.microscopeparts.eu/part/91056) is the same objective in the version without phase rings. Its description tells you more about using Carl Zeiss Jena objectives with an M19 thread.

Description of this part for the microscope.

21 microscope.

Basic parameters:
Manufacturer: Carl Zeiss Jena
Engraving on the objective: Planachromat 12.5x/0.25 ∞/0 Ph
Magnification: 12.5x
Numerical aperture N.A.: 0.25
Tube length: infinity (more precisely: 250 mm)
Optical correction: planachromatic
Cover glass: no - this objective is intended for work without a cover glass
Immersion: no - this is a so-called dry objective
Phase contrast: yes, a special phase contrast for work in reflected light
Polarisation: no - this is not a polarising objective
Thread: M19
Plan compensating eyepieces: yes, required - this objective needs eyepieces with additional correction (marked "PK" at Carl Zeiss Jena)
Direct projection and macro photography: no - this objective does not work in direct projection mode and is not suitable for macro photography with the objective attached directly to a camera

Phase contrast objectives for the Neophot microscopes have a phase ring built differently from the other Ph objectives made by Carl Zeiss Jena - instead of a continuous ring there is a three-segment pattern, somewhat reminiscent of a Wankel engine rotor. This is worth knowing, because it means that a phase contrast objective from a biological microscope will not replace this one in a Neophot, and the other way round.

The reason is a matter of design. In a metallurgical microscope the objective also acts as the condenser, so the illuminating light passes through the same pupil as the light forming the image. With a continuous ring the whole illumination would pass through the phase coating, which lets only part of the light through and reflects a fair amount of it - and those reflections would swamp the already faint phase contrast image. The solution turned out to be an odd number of segments: the image of the diaphragm formed after reflection off the specimen is rotated by 180 degrees, so with three segments it falls into the gaps between them. The illuminating light therefore enters beside the phase coating and returns through it. The solution is described in patent AT 295883 B.

The objective is offered together with its matching slider (Objektivwechselschlitten) with an M19 thread - and that is no coincidence. The position in which the phase sectors come to rest is decided by how far the objective screws into the thread, and every specimen stops slightly differently, which is why the factory selected objective and slider in pairs and wrote both numbers on the card in the case. Buying such a pair together avoids the whole problem - the objective already sits in relation to its slider exactly as it left the works.

Setting it up in the microscope needs neither a service technician nor a phase telescope - the Neophot has a built-in, swing-out Bertrand lens. The procedure is basically this: switch in the Bertrand lens, focus on the phase sectors and use the adjusting screws to bring the image of the sector diaphragm into coincidence with the image of the sectors in the objective; sometimes a slight rotation of the aperture diaphragm helps as well. Should the position of the glass in the sector diaphragm itself ever need correcting - it is held down by an ordinary threaded ring, so it can be turned. The whole thing resembles centring the phase rings in the condenser of a biological microscope.

Two more things are needed on the microscope side for work in phase contrast: the sector diaphragm (Sektorenblende), pushed in front of the open aperture diaphragm, and the auxiliary lens turret (Hilfslinsenrevolver) on the dovetail of the illuminator. The latter images the diaphragm exactly in the plane of the phase coating, which lies slightly differently in each objective - hence a separate auxiliary lens for every magnification. In bright field the objective of course works perfectly normally.

A note for the DIY-minded: an objective like this can be adapted for transmitted light, except that the diaphragm in the condenser is then set not opposite but in line with the segments of the objective, because there is no second pass through the pupil. Phase contrast should appear, but with stronger halo and a directional relief effect, since the gaps in the ring mean that part of the illumination azimuths is missing. On top of that comes the infinity design with no cover glass correction, so a tube lens will be needed. More of an experiment than a working solution - but doable in one evening.

The last photos in the gallery show:

* a photo of the original table indicating which serial numbers of the objective sliders are factory-paired with which serial numbers of the objectives
* two pages of errata to the instruction manual of the Carl Zeiss Jena Neophot 2 microscope.

The "compatibility" section lists, besides the Carl Zeiss Jena Neophot 21 microscope, those microscopes that this objective fits mechanically and optically. What result you get on them, however, can sometimes be a surprise.

Here (https://www.microscopeparts.eu/part/91056) you can read more about using Carl Zeiss Jena objectives with an M19 thread.

Description of this part for the microscope.

21 microscope.

Basic parameters:
Manufacturer: Carl Zeiss Jena
Engraving on the objective: Planachromat 6.3x/0.12 ∞/0 Ph
Magnification: 6.3x
Numerical aperture N.A.: 0.12
Tube length: infinity (more precisely: 250 mm)
Optical correction: planachromatic
Cover glass: no - this objective is intended for work without a cover glass
Immersion: no - this is a so-called dry objective
Phase contrast: yes, a special phase contrast for work in reflected light
Polarisation: no - this is not a polarising objective
Thread: M19
Plan compensating eyepieces: yes, required - this objective needs eyepieces with additional correction (marked "PK" at Carl Zeiss Jena)
Direct projection and macro photography: no - this objective does not work in direct projection mode and is not suitable for macro photography with the objective attached directly to a camera

Phase contrast objectives for the Neophot microscopes have a phase ring built differently from the other Ph objectives made by Carl Zeiss Jena - instead of a continuous ring there is a three-segment pattern, somewhat reminiscent of a Wankel engine rotor. This is worth knowing, because it means that a phase contrast objective from a biological microscope will not replace this one in a Neophot, and the other way round.

The reason is a matter of design. In a metallurgical microscope the objective also acts as the condenser, so the illuminating light passes through the same pupil as the light forming the image. With a continuous ring the whole illumination would pass through the phase coating, which lets only part of the light through and reflects a fair amount of it - and those reflections would swamp the already faint phase contrast image. The solution turned out to be an odd number of segments: the image of the diaphragm formed after reflection off the specimen is rotated by 180 degrees, so with three segments it falls into the gaps between them. The illuminating light therefore enters beside the phase coating and returns through it. The solution is described in patent AT 295883 B.

The objective is offered together with its matching slider (Objektivwechselschlitten) with an M19 thread - and that is no coincidence. The position in which the phase sectors come to rest is decided by how far the objective screws into the thread, and every specimen stops slightly differently, which is why the factory selected objective and slider in pairs and wrote both numbers on the card in the case. Buying such a pair together avoids the whole problem - the objective already sits in relation to its slider exactly as it left the works.

Setting it up in the microscope needs neither a service technician nor a phase telescope - the Neophot has a built-in, swing-out Bertrand lens. The procedure is basically this: switch in the Bertrand lens, focus on the phase sectors and use the adjusting screws to bring the image of the sector diaphragm into coincidence with the image of the sectors in the objective; sometimes a slight rotation of the aperture diaphragm helps as well. Should the position of the glass in the sector diaphragm itself ever need correcting - it is held down by an ordinary threaded ring, so it can be turned. The whole thing resembles centring the phase rings in the condenser of a biological microscope.

Two more things are needed on the microscope side for work in phase contrast: the sector diaphragm (Sektorenblende), pushed in front of the open aperture diaphragm, and the auxiliary lens turret (Hilfslinsenrevolver) on the dovetail of the illuminator. The latter images the diaphragm exactly in the plane of the phase coating, which lies slightly differently in each objective - hence a separate auxiliary lens for every magnification. In bright field the objective of course works perfectly normally.

A note for the DIY-minded: an objective like this can be adapted for transmitted light, except that the diaphragm in the condenser is then set not opposite but in line with the segments of the objective, because there is no second pass through the pupil. Phase contrast should appear, but with stronger halo and a directional relief effect, since the gaps in the ring mean that part of the illumination azimuths is missing. On top of that comes the infinity design with no cover glass correction, so a tube lens will be needed. More of an experiment than a working solution - but doable in one evening.

The last photos in the gallery show:

* a photo of the original table indicating which serial numbers of the objective sliders are factory-paired with which serial numbers of the objectives
* two pages of errata to the instruction manual of the Carl Zeiss Jena Neophot 2 microscope.

The "compatibility" section lists, besides the Carl Zeiss Jena Neophot 21 microscope, those microscopes that this objective fits mechanically and optically. What result you get on them, however, can sometimes be a surprise.

Here (https://www.microscopeparts.eu/part/91056) you can read more about using Carl Zeiss Jena objectives with an M19 thread.