Leitz Wetzlar - PZO
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Leitz Wetzlar - PZO
I purchased this condenser inexpensively on eBay. I asked the seller to measure the diameter of the condenser thinking that I could use it on my PZO Biolar. It is the correct diameter. It's in excellent condition. Not sure why I wanted to do this either, just experimenting I suppose. Obviously I know nothing about this condenser and was hoping that someone here might. That's why I'm asking. Any tips, suggestions on usage etc., would be appreciated.
-JW:
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Hi,
It's a Leitz darkfield condenser.
I'm not entirely sure which one. It looks like an oil immersion darkfield condenser (they usually have a high NA illumination cone; they only work with oil immersion, though sometimes water immersion also works).
To be on the safe side, test it without immersion first.
The top lens of the condenser looks a bit different from the later models, that's why I'm unsure. Some general information on using these condensers is found here: www.science-info.net/docs/leitz/darkfield_condenser.pdf
Regards, Ichty
It's a Leitz darkfield condenser.
I'm not entirely sure which one. It looks like an oil immersion darkfield condenser (they usually have a high NA illumination cone; they only work with oil immersion, though sometimes water immersion also works).
To be on the safe side, test it without immersion first.
The top lens of the condenser looks a bit different from the later models, that's why I'm unsure. Some general information on using these condensers is found here: www.science-info.net/docs/leitz/darkfield_condenser.pdf
Regards, Ichty
Last edited by Ichthyophthirius on Sat Mar 31, 2018 1:20 pm, edited 2 times in total.
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As they had the same condenser fitting (39.5 mm), it's possible to use the Leitz condenser on the PZO Biolar! Your condenser is much older than your Biolar.
Some more information about the "1/12" device:
It's an objective adapter and a funnel stop device ("Trichterblende"). You unscrew the bottom end of a Leitz oil immersion objective (of that time) with the lens group and screw it onto the 1/12 tunnel stop adapter.
This reduces the NA of the oil immersion objective down to NA 0.9, which makes it suitable for oil immersion. Alternatively, you can use high NA objectives with an inbuilt iris.
Have a look here, page 12: http://www.science-info.net/docs/leitz/Leitz-1920.pdf
As you can see on page 12, the famous Leitz logo is based on this type of darkfield condenser!
Some more information about the "1/12" device:
It's an objective adapter and a funnel stop device ("Trichterblende"). You unscrew the bottom end of a Leitz oil immersion objective (of that time) with the lens group and screw it onto the 1/12 tunnel stop adapter.
This reduces the NA of the oil immersion objective down to NA 0.9, which makes it suitable for oil immersion. Alternatively, you can use high NA objectives with an inbuilt iris.
Have a look here, page 12: http://www.science-info.net/docs/leitz/Leitz-1920.pdf
As you can see on page 12, the famous Leitz logo is based on this type of darkfield condenser!
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I haven't done much DF and yes I like it.Ichthyophthirius wrote:You don't like darkfield microscopy?
Stupidity time. I suppose I didn't understand that statement. I'm still learning. I got started super late in life with microscopy even though I joined the forum years ago. Everything has been a huge learning curve and there are many things I should know by now that I don't. Just being honest. Are you saying that I can use my Nikon Fluor 40x/1.30 objective with this particular condenser (and pretend that 1/12 brass adapter even exist)?Ichthyophthirius wrote: Alternatively, you can use high NA objectives with an inbuilt iris.
-JW:
Does the DF condenser have any number like 0.7-0.9 (dry) or 1.2-1.4 (oil) on it? It looks like a dry DF one, though I am not sure.
If you Nikon 40/1.3 (or any) objective has an Iris, then you don't need the 1/12 device. Just stop down the objective till you see DF. If it is a dry NA 0.7-0.9 DF condenser, you will need to stop down your NA 1.3 max iris to minimum.
Oil DF condenser has to be used with oil immersion between its top lens and bottom of microscope slide. Adjustment of condenser and perfect centration of condenser is needed for good DF.
If you Nikon 40/1.3 (or any) objective has an Iris, then you don't need the 1/12 device. Just stop down the objective till you see DF. If it is a dry NA 0.7-0.9 DF condenser, you will need to stop down your NA 1.3 max iris to minimum.
Oil DF condenser has to be used with oil immersion between its top lens and bottom of microscope slide. Adjustment of condenser and perfect centration of condenser is needed for good DF.
Selling my Canon FD 200mm F/2.8 lens
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The Leitz DF condenser may be a paraboloid type. Many companies produced both a cardioid oil condenser as well as a paraboloid oil condenser. I have a similar vintage cardioid type, Leitz DF condenser and as Ichthyophthyrius mentions, yours doesn't look the same. I am not sure dry condensers were made in those days, a variable rosette stop being perfectly usable along with a BF condenser.
The advantage of a paraboloid condenser is that, they work a little better at low magnifications, providing a fuller illumination field, so DF can be effected at 40X or below. Typically, with older cardioid condensers, the DF limit is 40X and up, depending on the f.o.v. required.
The advantage of a paraboloid condenser is that, they work a little better at low magnifications, providing a fuller illumination field, so DF can be effected at 40X or below. Typically, with older cardioid condensers, the DF limit is 40X and up, depending on the f.o.v. required.
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Thanks for the help/suggestions. I haven't been able to figure out how to use this DF condenser with my PZO. I have not tried to oil the underside of the side either. I simply thought this would be an easy setup on the PZO. I 'thought' that I would at least be able to see 'some illumination' on the very edge of the field of view, knowing that it wouldn't be perfectly centered but I saw nothing. Obviously I tried centering the condenser stop by adjusting the centering screws but still saw absolutely no light. I tried using two different Nikon objectives with adjustable collars, a 40x and 60x with no luck. My PZO power supply was set to max illumination. Of course I could be doing something wrong. I've struggled with just about everything since I started microscopy.
The distance of the top glass of the condenser to the slide is critical: in many cases it must be almost touching it. If it is an oil condenser you wouldn't see any light with it without oiling it to the slide (if you haven't immersion oil a drop of distilled water could work just for testing) .
To test centering and illumination a low power (10X - 20X) objective is good even if you have not the whole field illuminated.
If the objective NA is too large for the DF condenser you still must be able to see the sample illuminated, although not with dark ground.
To test centering and illumination a low power (10X - 20X) objective is good even if you have not the whole field illuminated.
If the objective NA is too large for the DF condenser you still must be able to see the sample illuminated, although not with dark ground.
Pau
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Thanks for the help and suggestions. I got it working. I tried a Leitz Wetzlar 40/0.75 Fluoreszenz objective. I oiled the underside of the diatom slide. I actually saw something although VERY dim. This is 3.2 sec, ISO 200 (totally manipulated in PS since it was so dark) single shot image. This particular diatom is very large. I will try another slide later on this evening but with a Nikon 40x/0.95.
-JW:
-JW:
Last edited by Smokedaddy on Tue Apr 03, 2018 8:00 pm, edited 1 time in total.