Although I've got a great collection of 160mm Zeiss west microscopes now, I've been curious about the advantages on the infinite system for photography so have been slowly collecting bits. I've now got an Axioplan and 3 Plan Neofluars, but no condenser or holder (ex-fluorescence scope).
I had planned to make an adapter to bolt on a spare 160mm condenser holder from a Universal, but offering it up to the right location projects an image of the filament onto the specimen plane. Are the optical pathways fundamentally different?
Zeiss infinite condensers
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apochronaut
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Re: Zeiss infinite condensers
Refracting condensers have a front focal length and a back focal length. The back focal length is very similar between condensers because they all have to focus at a similar distance to the object but the front focal length will vary , depending on the location of the illuminator or field plane if for a Köhler system.. Condensers from very old microscopes that used remote illuminators likely are focused at infinity but condensers from very long microscopes with rear mounted illuminators might be too or have a very long finite focal length, depending on where the field plane is located.
Most modern condensers, whether from a finite or infinity corrected microscope are going to have a finite front focal length.
A non- native condenser needs to have a front focal length fairly close to the microscope's requirements because even though you can adjust the condenser focus on the track to achieve Köhler, that will alter the back focus some. Since Köhler is achieved by focusing the condenser on the field plane, a donor microscope from which you are taking a condenser , should have an object to field plane measure very close to that of your receiving microscope. I would say then, that rather than a potential condenser being brand specific, it should just measure up ; in focal length, field coverage, correction, height and mount.
One thing to be aware of is the smaller f.o.v. in the past, even with many fairly recent finite microscopes. Many condensers were not required to produce an illuminated spot on the stage as large as that required today because the f.o.v. was only 18mm or even less.
Some illumination systems also used ground glass filters in order to help blur the filament image.
Most modern condensers, whether from a finite or infinity corrected microscope are going to have a finite front focal length.
A non- native condenser needs to have a front focal length fairly close to the microscope's requirements because even though you can adjust the condenser focus on the track to achieve Köhler, that will alter the back focus some. Since Köhler is achieved by focusing the condenser on the field plane, a donor microscope from which you are taking a condenser , should have an object to field plane measure very close to that of your receiving microscope. I would say then, that rather than a potential condenser being brand specific, it should just measure up ; in focal length, field coverage, correction, height and mount.
One thing to be aware of is the smaller f.o.v. in the past, even with many fairly recent finite microscopes. Many condensers were not required to produce an illuminated spot on the stage as large as that required today because the f.o.v. was only 18mm or even less.
Some illumination systems also used ground glass filters in order to help blur the filament image.
Re: Zeiss infinite condensers
Thanks for the response.
What you've written matches my understanding. The physical distances on the stands are quite similar, but the optical configuration is obviously quite different. The Universal does have a (removable) diffuser in front of the lamp, but without it the filament is in focus in the back focal plane, not on the stage. The other obvious difference is the light path is much larger at the lamp end on the Axio.
What you've written matches my understanding. The physical distances on the stands are quite similar, but the optical configuration is obviously quite different. The Universal does have a (removable) diffuser in front of the lamp, but without it the filament is in focus in the back focal plane, not on the stage. The other obvious difference is the light path is much larger at the lamp end on the Axio.
Re: Zeiss infinite condensers
I have a spare condenser from an Axiolab. If you're interested pm me,it has been sitting in the drawer for too long.