Slide is sitting on swing-out lens on top of condenser - Leitz SM LUX

[martinr]

On the Leitz SM LUX I recently bought, I've set up Kohler illumination, and I notice that even when the condenser is lowered to its lowest position, the swing-out lens protrudes about 1mm above the level of the stage, so the slide sits on this lens and is free to rock.

From fully up to fully down, the condenser has a movement range of about 1mm.

The manual says this swing-out lens should be used (ie swung in below the slide) for all objectives with an NA greater than 0.25, which means any objective stronger than x10. It's part of the condenser and rises and falls as the condenser is moved. Around the side of this swing-out lens is "oel 1.25"

I managed to set up Kohler using the instructions with the lens swung in but it was then that I noticed the slide is in contact with this lens rather than resting on the stage. If I place 2 fingers on the slide and swing the lens in, I feel the slide lift.

Surely this can't be right? And if, somehow, the condenser were to be lowered such that contact was not made with the slide, then it would not be possible to set up Kohler.

Any advice gratefully received.

Martin

[mrsonchus]

Hi martinr, are you able to post an image of the 'scope and it's condenser (including a bottom-view of the condenser)?

John B.

[martinr]

Sorry: It's been a devil of a job getting the photos onto the forum.

Hello again, John B and thanks. Sorry: post a picture is just what I would have asked for on the forum I frequent!

The problem - slide sat on swing-out lens rather than stage:




https://doc-0s-40-docs.googleuserconten ... e=download

I removed the polarising filter for clarification.

Photo of condenser with swing-out lens in place:


https://drive.google.com/open?id=0B1OSc ... jNZNFV0VXM


Photo of condenser with swing-out lens swung out:


https://drive.google.com/open?id=0B1OSc ... llzOUR6b00

So if I could put a spacer under each end of the slide to lift it so it's just clear of the lens, that should solve it; therefore, if I could raise the stage a fraction relative to the condenser (or drop the condenser relative to the stage?), I think the problem would be solved and the slide would sit on the stage with the swing out lens just below. I think ..... I notice there's a Allen screw inside the knurled knob of the condenser focussing (height adjustment) knurled knob, and I had to adjust that to focus the field iris for Kohler; I'm wondering if that's the key, but I'd rather seek guidance first.

[mrsonchus]

Hmm, there are others on this forum with a lot more knowledge than I have, but might this be a case of 'the missing supplemental lens' - that is to say the 'K1' insert for the bottom of the condenser that facilitates sharp-focus of the field-iris ala-Kohler?

I'll be back later with some actual images of my SM-LUX with and without it's K1 insert that may help you....

Back later.

[martinr]

Hmm, there are others on this forum with a lot more knowledge than I have, but might this be a case of 'the missing supplemental lens' - that is to say the 'K1' insert for the bottom of the condenser that facilitates sharp-focus of the field-iris ala-Kohler?

I'll be back later with some actual images of my SM-LUX with and without it's K1 insert that may help you....

Back later.

Thanks John.

Think I've sorted it, but I'd like to know about the K1 insert please. Not heard about that before.

Anyway, the seller said he'd wound the condenser all the way up for transit. As I could only get 90 degrees of motion on the knurled knob and 1mm of travel, I realised that was abnormal. So I fully released the Allen screw inside the condenser's knurled knob and then got a good range of movement.

I can't test it as the 6V bulb burnt out, so I've got some on order and have been advised to stock up whilst they are still available.

Anyway, I'd really appreciate knowing more about the K1 unit.

Martin

[mrsonchus]

Aha - yes the 'K1' lens is inserted into the bottom of the 'std 600-series' condenser to make it perfect for the SM_LUX and others, the Orthoplan (I have both 'scopes and both K1 and K4 inserts) 'converts' the condenser to the Orthoplan, apparently and according to Leitz documentation.
I made a few tests this afternoon and the results as far as I'm concerned are as follows, although these are not empirical, only my own subjective results.
Coincidentally I also have, and use permanently on my Orthoplan, the same condenser and top-lens as yours, namely the oel 1.25 n.a. although mine is also marked 'apl' (aplanatic I think) and I therefore was able to make quite a close comparison. My SM-LUX has a 0.90 n.a. 'as' condenser top-lens and of course the fitted 'K1'.

Here they both are, with their respective adapter-lenses removed...

ws_DSCN9303.jpg (71.4 KiB) Viewed 6452 times

Placing the K1 adapter into my Orthoplan's 1.25 n.a. condenser similar to yours, the K1 seemed to me to make no difference in the ability of the condenser to fill the FOV or to sharpen the edges of the field-iris as for Kohler. I'm able to focus the field-iris well when using the 1.25 condenser on the SM-LUX with or without the K1 insert - this surprisingly is also the case when using the 0.9 n.a. condenser with and without the K1 insert, with the SM-LUX.....

That said, this is how the K1/K4 fits into the base of the condenser - first image is with the lens part-way inserted, the second is fully-fitted and therefore flush with the condenser's base...

ws_DSCN9310.jpg (43.04 KiB) Viewed 6452 times

and,

ws_DSCN9306.jpg (43.89 KiB) Viewed 6452 times

My advice would be to forget about the K1 at the moment as it may not fix your problem - in honesty I can't see what difference it makes to the SM-LUX Kohler set-up. The objectives used for the test were a x4, ax10, ax25, x40 and x70 - top lens swung out for the x4 of course.

Sorry this doesn't really help much.

p.s. one thing I will say, is that the 1.25 n.a. (when used with oel of course) condenser gave a far superior image with every objective, more detail (resolution?) and more contrast - oh yes, and a sharper focus of the field diaphragm. Whatever else you do - hang onto that condenser - if it's like mine it's a beauty.

[mrsonchus]

Oh yes, forgot to mention the bulb - I use an bog-std 6V motorbike bulb of exactly the same spec and dimensions as the original, and it works perfectly.
Here's a link to the ones I use (I'm still on the first bulb from the packet),
bulbs for SM-LUX

They fit and work perfectly, and cost £1.50 each!

The Orthoplan and SM-LUX,

ws_small_DSCN8794.jpg (43.17 KiB) Viewed 6451 times

Good luck. John B.

[martinr]

Aha - yes the 'K1' lens is inserted into the bottom of the 'std 600-series' condenser to make it perfect for the SM_LUX and others, the Orthoplan (I have both 'scopes and both K1 and K4 inserts) 'converts' the condenser to the Orthoplan, apparently and according to Leitz documentation.
I made a few tests this afternoon and the results as far as I'm concerned are as follows, although these are not empirical, only my own subjective results.
Coincidentally I also have, and use permanently on my Orthoplan, the same condenser and top-lens as yours, namely the oel 1.25 n.a. although mine is also marked 'apl' (aplanatic I think) and I therefore was able to make quite a close comparison. My SM-LUX has a 0.90 n.a. 'as' condenser top-lens and of course the fitted 'K1'.

Here they both are, with their respective adapter-lenses removed...
ws_DSCN9303.jpg

Placing the K1 adapter into my Orthoplan's 1.25 n.a. condenser similar to yours, the K1 seemed to me to make no difference in the ability of the condenser to fill the FOV or to sharpen the edges of the field-iris as for Kohler. I'm able to focus the field-iris well when using the 1.25 condenser on the SM-LUX with or without the K1 insert - this surprisingly is also the case when using the 0.9 n.a. condenser with and without the K1 insert, with the SM-LUX.....

That said, this is how the K1/K4 fits into the base of the condenser - first image is with the lens part-way inserted, the second is fully-fitted and therefore flush with the condenser's base...
ws_DSCN9310.jpg
and,
ws_DSCN9306.jpg

My advice would be to forget about the K1 at the moment as it may not fix your problem - in honesty I can't see what difference it makes to the SM-LUX Kohler set-up. The objectives used for the test were a x4, ax10, ax25, x40 and x70 - top lens swung out for the x4 of course.

Sorry this doesn't really help much.

p.s. one thing I will say, is that the 1.25 n.a. (when used with oel of course) condenser gave a far superior image with every objective, more detail (resolution?) and more contrast - oh yes, and a sharper focus of the field diaphragm. Whatever else you do - hang onto that condenser - if it's like mine it's a beauty.

Thanks for going to all that trouble, John. Where the K1 would fit, is where my polarising attachment fits. And I find it quite useful to play with, sometimes showing a detail or 2 that otherwise would have got missed.

Your p.s. prompted yet another "aha" moment: Am I supposed to put a drop of immersion oil on top of that lens? So when using, say, a x40 objective, which would not have oil between the objective and the specimen, I might well have, for best results, a drop of oil between that swing-out lens and the underside of the slide?

It would all make sense to me; a little bell did ring when I saw "oel" on the side of the lens.

How do you clean the oil off? I saw a recommendation to use xylene, and what would you use as the carrier, a soft, lint-free cloth?

I see you have a sticker on the front denoting the services of the microscope; do you send it for servicing?

[Hobbyst46]

Martin,
On some Zeiss and Olympus microscopes the condenser rack has an upper "stopper". That is to say, when the condenser rack is not installed on the microscope, the vertical movement range is wider - centimeters, not millimeters. And you can raise it so it is higher than the stage itself.
However, there is a small screw in the microscope condenser carrier (I mean, the vertical plate onto which the rack is connected). Say on the top left point of the rack. And this is the stopper: It prevents the swing-out lens from lifting the slide.
Maybe there was such a stopper screw on the microscope, and it is missing or its head is worn out. Look for an empty hole and tap?
Incidentally, for some very specific experiments users remove the stopper to have the condenser lens rise above the stage. But I doubt that this is the case.
Hope that helps.

[martinr]

Aha - yes the 'K1' lens is inserted into the bottom of the 'std 600-series' condenser to make it perfect for the SM_LUX and others, the Orthoplan (I have both 'scopes and both K1 and K4 inserts) 'converts' the condenser to the Orthoplan, apparently and according to Leitz documentation.
I made a few tests this afternoon and the results as far as I'm concerned are as follows, although these are not empirical, only my own subjective results.
Coincidentally I also have, and use permanently on my Orthoplan, the same condenser and top-lens as yours, namely the oel 1.25 n.a. although mine is also marked 'apl' (aplanatic I think) and I therefore was able to make quite a close comparison. My SM-LUX has a 0.90 n.a. 'as' condenser top-lens and of course the fitted 'K1'.

Here they both are, with their respective adapter-lenses removed...
ws_DSCN9303.jpg

Placing the K1 adapter into my Orthoplan's 1.25 n.a. condenser similar to yours, the K1 seemed to me to make no difference in the ability of the condenser to fill the FOV or to sharpen the edges of the field-iris as for Kohler. I'm able to focus the field-iris well when using the 1.25 condenser on the SM-LUX with or without the K1 insert - this surprisingly is also the case when using the 0.9 n.a. condenser with and without the K1 insert, with the SM-LUX.....

That said, this is how the K1/K4 fits into the base of the condenser - first image is with the lens part-way inserted, the second is fully-fitted and therefore flush with the condenser's base...
ws_DSCN9310.jpg
and,
ws_DSCN9306.jpg

My advice would be to forget about the K1 at the moment as it may not fix your problem - in honesty I can't see what difference it makes to the SM-LUX Kohler set-up. The objectives used for the test were a x4, ax10, ax25, x40 and x70 - top lens swung out for the x4 of course.

Sorry this doesn't really help much.

p.s. one thing I will say, is that the 1.25 n.a. (when used with oel of course) condenser gave a far superior image with every objective, more detail (resolution?) and more contrast - oh yes, and a sharper focus of the field diaphragm. Whatever else you do - hang onto that condenser - if it's like mine it's a beauty.

Thanks for going to all that trouble, John. Where the K1 would fit, is where my polarising attachment fits. And I find it quite useful to play with, sometimes showing a detail or 2 that otherwise would have got missed.

Your p.s. prompted yet another "aha" moment: Am I supposed to put a drop of immersion oil on top of that lens? So when using, say, a x40 objective, which would not have oil between the objective and the specimen, I might well have, for best results, a drop of oil between that swing-out lens and the underside of the slide?

It would all make sense to me; a little bell did ring when I saw "oel" on the side of the lens.

How do you clean the oil off? I saw a recommendation to use xylene, and what would you use as the carrier, a soft, lint-free cloth?

I see you have a sticker on the front denoting the services of the microscope; do you send it for servicing?

Oh yes, forgot to mention the bulb - I use an bog-std 6V motorbike bulb of exactly the same spec and dimensions as the original, and it works perfectly.
Here's a link to the ones I use (I'm still on the first bulb from the packet),
bulbs for SM-LUX

They fit and work perfectly, and cost £1.50 each!

The Orthoplan and SM-LUX,
ws_small_DSCN8794.jpg

Good luck. John B.

Hi John

Will you PM me with your address? I already ordered a load of bulbs from eBay (as a 10 pack), especially as my local electrical suppliers told me to stock up well. And having run round today looking for a 6V bulb, I see his point. My bulb burned out; he reckoned the shocks of transit weakened the vacuum seal - the bulb was 'silvered' on the inside, consistent with a lost vacuum.

Anyway, I'll have more bulbs than I'll ever need, so I'd like to send you some as thanks for your help.

By the way, the seller of the 'scope said a 12V bulb would work. I was sceptical, but, whilst waiting for the 6V bulbs to arrive, I stuck a 12V BA15S in - to help me sort out the condenser problem - and it does indeed work. The light has a distinct red/yellow hue, but it is more than adequate up to and including a x40. (I found a x100 oil immersion objective on eBay, which has not yet arrived, but if it arrives before the 6V bulbs, I'll see whether the 12V bulb has enough oomph for that.). It's already taught me a lesson: more light isn't necessarily better, and can even be detrimental. Certainly, I have no desire to experiment with any other form of light.

Martin

[martinr]

Martin,
On some Zeiss and Olympus microscopes the condenser rack has an upper "stopper". That is to say, when the condenser rack is not installed on the microscope, the vertical movement range is wider - centimeters, not millimeters. And you can raise it so it is higher than the stage itself.
However, there is a small screw in the microscope condenser carrier (I mean, the vertical plate onto which the rack is connected). Say on the top left point of the rack. And this is the stopper: It prevents the swing-out lens from lifting the slide.
Maybe there was such a stopper screw on the microscope, and it is missing or its head is worn out. Look for an empty hole and tap?
Incidentally, for some very specific experiments users remove the stopper to have the condenser lens rise above the stage. But I doubt that this is the case.
Hope that helps.

I do indeed have that tiny stopper screw, thankfully, to stop the lens overshooting. I solved the problem: the previous owner wound the condenser fully up for transit, and it had got stuck. By releasing the Allen screw in the knob that moves the condenser up and down, I freed it. So instead of only being able to rotate the knob through 90 degrees with 1mm of up-down movement, I now have the full range of movement. AND, the lens sits where it's supposed to: a fraction below the underside of the slide. Frustrating, but an excellent lesson forcing me to pay close attention to the condenser and the underside of the stage.

Many thanks

Martin

[mrsonchus]

Thanks for going to all that trouble, John. Where the K1 would fit, is where my polarising attachment fits. And I find it quite useful to play with, sometimes showing a detail or 2 that otherwise would have got missed.

Your p.s. prompted yet another "aha" moment: Am I supposed to put a drop of immersion oil on top of that lens? So when using, say, a x40 objective, which would not have oil between the objective and the specimen, I might well have, for best results, a drop of oil between that swing-out lens and the underside of the slide?

It would all make sense to me; a little bell did ring when I saw "oel" on the side of the lens.

How do you clean the oil off? I saw a recommendation to use xylene, and what would you use as the carrier, a soft, lint-free cloth?

I see you have a sticker on the front denoting the services of the microscope; do you send it for servicing?

Oil between top lens and slide-bottom...
Not all the time. The oil on the condenser's top lens is only needed when using an objective of n.a. >= 1, as in theory air-gap (i.e. no-oil) can give an n.a. up to 1.
I think in actual use, objectives nearly always operate, by varying degrees, below their stated (engraved on the barrel) n.a.. This is simply because to realise the full n.a. of the objective Kohler must be set and the condenser's n.a. (set by opening/closing the condenser's diaphragm) must be set to match the n.a. of the objective in use.

This situation arises/is achieved when the condenser's iris opening exactly matches the size of the objective's field as seen if examined with a 'phase telescope' device that enables not only the alignment of objectives with phase-rings in them (another topic entirely) but the rear objective aperture when the PT is inserted in place of an eyepiece for this task.
The PT is able to be focused on the back-plane of the objective and so the alterations of the condenser's iris are able to be seen clearly as the iris (condenser's) is closed/opened.
In practice though It's pretty easy to simply peer into an eyepiece tube (eyepiece removed) and watch as you adjust the condenser's iris - you'll see when it impinges on the back-view of the objective - no PT really needed - a luxury really - and they're not cheap!

With the exact match of iris opening and objective's back-aperture width - theoretically n.a. is equal for the condenser and the objective, and the stated n.a. is achieved, which maximises the resolution of the objective. But, that image when viewed normally through the eyepieces will lack contrast and probably depth of focus. In practice the condenser's iris needs to be closed past this exact position until a very slight darkening of the image is noticed - this gives the best observable image in terms of balancing resolution (as a function of n.a.), depth of focus and contrast.

Sooo, a condenser will usually be best set to give a slightly lower than maximum n.a. - making say a 0.9 n.a. condenser perfectly fine for use with any dry objective below n.a. 1.
The 1.25 oel (oil) immersion is used for objectives above n.a. 1 (oil needed between slide and objective and between condenser top lens and slide) WITH oil, or without oil for any other dry objective.

In a nutshell - oil must be used for both the objective and condenser for an oil-immersion objective - meaning an oil-immersion condenser is needed to make best use of an oil (oel) immersion objective...

I find the better an objective's contrast - namely with Fl objectives (for Leitz) is, the wider I can open the condenser's iris and the closer I can then get to the magical condenser-objective n.a. match. Consequently I find that the Fl objectives (which due to the optical characteristics of their construction and glass-composition usually have a higher n.a. than a non-Fl version of the same magnification) give me appreciably higher resolution/n.a. and very much more contrast - the most important factor of all I find for my stained brightfield mounted slides - especially for photomicrography..

I usually clean the oil off with several dabs/very slight single wipes, of a soft tissue then a final repeat with a touch of spectacle-spray works well - I use no strong solvents such as xylene, acetone or alcohol. For objectives in general I use de-ionised water. The secret is never use the same piece of tissue, cloth or cotton-bud etc for more than a single smooth wipe - cut your soft cloth etc into small pieces - use each one once then discard - this really does remove any muck very effectively I find - don't attempt to 'polish' as if cleaning a window.. Always use a 'puffer' first and last too!

Hope this helps a little.

Oh - I'm very pleased to help if I can, I've received so much help since joining this forum (the only one I use) as a complete beginner I'm just pleased to pass-on some of that which I've been taught here.

[martinr]

Thanks for going to all that trouble, John. Where the K1 would fit, is where my polarising attachment fits. And I find it quite useful to play with, sometimes showing a detail or 2 that otherwise would have got missed.

Your p.s. prompted yet another "aha" moment: Am I supposed to put a drop of immersion oil on top of that lens? So when using, say, a x40 objective, which would not have oil between the objective and the specimen, I might well have, for best results, a drop of oil between that swing-out lens and the underside of the slide?

It would all make sense to me; a little bell did ring when I saw "oel" on the side of the lens.

How do you clean the oil off? I saw a recommendation to use xylene, and what would you use as the carrier, a soft, lint-free cloth?

I see you have a sticker on the front denoting the services of the microscope; do you send it for servicing?

Oil between top lens and slide-bottom...
Not all the time. The oil on the condenser's top lens is only needed when using an objective of n.a. >= 1, as in theory air-gap (i.e. no-oil) can give an n.a. up to 1.
I think in actual use, objectives nearly always operate, by varying degrees, below their stated (engraved on the barrel) n.a.. This is simply because to realise the full n.a. of the objective Kohler must be set and the condenser's n.a. (set by opening/closing the condenser's diaphragm) must be set to match the n.a. of the objective in use.

This situation arises/is achieved when the condenser's iris opening exactly matches the size of the objective's field as seen if examined with a 'phase telescope' device that enables not only the alignment of objectives with phase-rings in them (another topic entirely) but the rear objective aperture when the PT is inserted in place of an eyepiece for this task.
The PT is able to be focused on the back-plane of the objective and so the alterations of the condenser's iris are able to be seen clearly as the iris (condenser's) is closed/opened.
In practice though It's pretty easy to simply peer into an eyepiece tube (eyepiece removed) and watch as you adjust the condenser's iris - you'll see when it impinges on the back-view of the objective - no PT really needed - a luxury really - and they're not cheap!

With the exact match of iris opening and objective's back-aperture width - theoretically n.a. is equal for the condenser and the objective, and the stated n.a. is achieved, which maximises the resolution of the objective. But, that image when viewed normally through the eyepieces will lack contrast and probably depth of focus. In practice the condenser's iris needs to be closed past this exact position until a very slight darkening of the image is noticed - this gives the best observable image in terms of balancing resolution (as a function of n.a.), depth of focus and contrast.

Sooo, a condenser will usually be best set to give a slightly lower than maximum n.a. - making say a 0.9 n.a. condenser perfectly fine for use with any dry objective below n.a. 1.
The 1.25 oel (oil) immersion is used for objectives above n.a. 1 (oil needed between slide and objective and between condenser top lens and slide) WITH oil, or without oil for any other dry objective.

In a nutshell - oil must be used for both the objective and condenser for an oil-immersion objective - meaning an oil-immersion condenser is needed to make best use of an oil (oel) immersion objective...

I find the better an objective's contrast - namely with Fl objectives (for Leitz) is, the wider I can open the condenser's iris and the closer I can then get to the magical condenser-objective n.a. match. Consequently I find that the Fl objectives (which due to the optical characteristics of their construction and glass-composition usually have a higher n.a. than a non-Fl version of the same magnification) give me appreciably higher resolution/n.a. and very much more contrast - the most important factor of all I find for my stained brightfield mounted slides - especially for photomicrography..

I usually clean the oil off with several dabs/very slight single wipes, of a soft tissue then a final repeat with a touch of spectacle-spray works well - I use no strong solvents such as xylene, acetone or alcohol. For objectives in general I use de-ionised water. The secret is never use the same piece of tissue, cloth or cotton-bud etc for more than a single smooth wipe - cut your soft cloth etc into small pieces - use each one once then discard - this really does remove any muck very effectively I find - don't attempt to 'polish' as if cleaning a window.. Always use a 'puffer' first and last too!

Hope this helps a little.

Oh - I'm very pleased to help if I can, I've received so much help since joining this forum (the only one I use) as a complete beginner I'm just pleased to pass-on some of that which I've been taught here.

Thank you, John, for such a clear, lucid and understandable explanation. It's not only greatly clarified what I'd read and seen in the manual and on the Internet, but also explained how to implement it in practice for best results.

Thanks also for the much-valued advice on cleaning.