Just bought Leitz objective...

[mrsonchus]

Hi all, I just spotted and snapped-up a Leitz Plan 170mm TL x1 0.04 n.a. objective. It also appears to have a correction-collar from the images! Presumably the collar is there because the '-' mark means for use with-or-without a cover-slip rather than the '0' mark that means without?
Anyone know what the mention of "large field condenser on dovetail carrier" may mean in the Leitz spec listing?

ws_leitz-x1-objective.jpg (31.02 KiB) Viewed 10365 times

Looking in the Leitz objective & condenser spec catalogue this objective is listed as,

ws_spec for leitz-x1-objective.jpg (15.34 KiB) Viewed 10365 times

I'm hoping this will reduce or even remove the need to stitch images for a whole slide's section as needed when using the x4 objective. Perhaps that will also reduce the dreaded uneven background of those low-power stitches. We'll soonsee! I'll post some images from it as soon as I receive it - hopefully this coming week....

Back when it arrives - it's the only one I've ever seen - it 'just appeared' listed - I'd looked not more than 30mins before and it wasn't listed....

Exciting to grab this one!

[Micro-Bob]

Hi John,
in your text there is written " iris diaphragm". Is this ring the control for the diaphragm?

Bob

[MichaelG.]

John,

I stand to be corrected, but I am sure that 'built-in iris diaphragm' is not the same thing as 'correction collar' ... I think you will find that the diaphragm serves exactly the same purpose as the one in a camera lens.

I have never seen a low power objective that needed a correction collar.

It should, nevertheless, give you lovely views and images.

MichaelG.
[ just slightly envious ]
.
P.S. The requisite condenser will be similar but not identical to this one https://goo.gl/images/BKYj2J ... i.e. a 'Spectacle Lens'.

[mrsonchus]

Hi John,
in your text there is written " iris diaphragm". Is this ring the control for the diaphragm?

Bob

Aha! yes - didn't even notice - got a little over-excited I think....

Thanks Bob.

[mrsonchus]

John,

I stand to be corrected, but I am sure that 'built-in iris diaphragm' is not the same thing as 'correction collar' ... I think you will find that the diaphragm serves exactly the same purpose as the one in a camera lens.

I have never seen a low power objective that needed a correction collar.

It should, nevertheless, give you lovely views and images.

MichaelG.
[ just slightly envious ]

Aha Michael - yes, I see - erm... what does one do with the built-in iris diaphragm. Sorry that's a stupid question but I've never encountered an objective with this feature. How is it used in practice Michael? Will I be OK to view my cover-slipped permanently-mounted thin sections with it as an over-view for scanning etc and full-section images with perhaps reduced need for stitching?

Thanks Michael

[Charles]

Large field condenser, I think, is referring to a condenser with an NA which will give a full field of view for your 0.04 NA on the objective. I know with my Zeiss 1X objective, I need to remove the condenser and just use the direct light so it fills the field of view.

[mrsonchus]

Large field condenser, I think, is referring to a condenser with an NA which will give a full field of view for your 0.04 NA on the objective. I know with my Zeiss 1X objective, I need to remove the condenser and just use the direct light so it fills the field of view.

Thanks Charles, yes that's what I do with my x4 objective and often the x10 also - I swing the top lens out then lower the condenser a little, or just slip it out altogether - probably need to remove it altogether for the x1? Easy enough with the Orthoplan - just slip it out of the dovetail rail.

Any idea how to use the built-in iris of this objective Charles?

John B.

[MichaelG.]

Aha Michael - yes, I see - erm... what does one do with the built-in iris diaphragm. Sorry that's a stupid question but I've never encountered an objective with this feature. How is it used in practice Michael?

Full aperture will give you the highest resolution, and the brightest image, but minimum depth of field.
Reducing the aperture [smaller hole in the diaphragm] will give greater d-o-f but lower resolution and reduced brightness.
... It's a case of 'Swings and Roundabouts'

MichaelG.

[mrsonchus]

Full aperture will give you the highest resolution, and the brightest image, but minimum depth of field.
Reducing the aperture [smaller hole in the diaphragm] will give greater d-o-f but lower resolution and reduced brightness.
... It's a case of 'Swings and Roundabouts'

MichaelG.

Ah, yes I see Michael, will closing the iris raise contrast also, which can be handy at such a low magnification I think?

Thanks Michael for your help.

[MichaelG.]

Ah, yes I see Michael, will closing the iris raise contrast also, which can be handy at such a low magnification I think?

Probably not [much], John ... but you may find that closing it just a little does improve things [as it does on many camera lenses]. That said: One would hope that Leitz carefully optimised the design.

I think using the appropriate condenser [check the edit on my earlier post] will make a significant improvement to contrast though.

I look forward to seeing the results.
MichaelG.

[mrsonchus]

Probably not [much], John ... but you may find that closing it just a little does improve things [as it does on many camera lenses]. That said: One would hope that Leitz carefully optimised the design.

I think using the appropriate condenser [check the edit on my earlier post] will make a significant improvement to contrast though.

I look forward to seeing the results.
MichaelG.

Ah,sounds a lot like the equivalent of the old 'swing-in' 'bull'seye' lens that used to be needed below the 1.25 Abbe condenser on my SP200 'scope - without it the Abbe couldn't fill the x4 objective - although removing the condenser worked, but wasn't quite as easy and quick as sliding the Orthoplan's condenser out. The Orthoplan's condenser (600 series lower element and body 'bathtub') fills the x4 objective fine with the top lens swung out, but I suspect the x1 objective may need the condenser out as well... Easy enough to do though - it will be really handy for me to be able to see and hopefully photograph more of a slide in a single image....

Fingers crossed it works OK. Thanks Michael.

p.s. do you think it may work for whole tissue (i.e. not flat and sectioned) with incident illumination too to some extent? That would be very useful also.

[apochronaut]

the iris in low power objectives seems somewhat counter intuitive at first but does have some uses in terms of depth of field enhancement and as well in the older objectives, it was probably a feature primarily useful for transmission fluorescence, where scattered rays from outside the aperture could negatively affect the results.

[mrsonchus]

the iris in low power objectives seems somewhat counter intuitive at first but does have some uses in terms of depth of field enhancement and as well in the older objectives, it was probably a feature primarily useful for transmission fluorescence, where scattered rays from outside the aperture could negatively affect the results.

Yes, it sounds as though it may be useful for incident lighting of whole uncovered/mounted tissue also - the iris may help with DOF perhaps as an aid to stacking for example an incidentally-lit, maybe even obliquely, seed or leaf piece? That would be really handy as an extra capability...

I'll be watching the post-box this week!

Thanks apo'

[MichaelG.]

p.s. do you think it may work for whole tissue (i.e. not flat and sectioned) with incident illumination too to some extent? That would be very useful also.

Yes, I think it should be fine.

You may, however, find it useful to experiment with lighting arrangements; because there is quite a high risk of internal reflections from the wall of the barrel if you go too oblique [and that will lower the contrast] ... I would probably play around with a Lieberkühn reflector and a lens hood, to explore the range of options.

I'm getting really interested to see how good this one is !!

MichaelG.
.
For info. this is my RMS threaded Olympus 20mm f3.5 macro lens with its Lieberkühn reflector fitted.

[MichaelG.]

The Orthoplan's condenser (600 series lower element and body 'bathtub') fills the x4 objective fine with the top lens swung out, but I suspect the x1 objective may need the condenser out as well...

At the risk of labouring this, John
[a foolish thing for me to do, given that I have never used the objective in question]
Yes, you will almost certainly need to remove the 'bathtub' but for optimum results, I think the specified 'low power condenser' [or a home made equivalent] would be beneficial. ... The trick, as ever, being to put only 'useful' light into the lens.

MichaelG.

[mrsonchus]

At the risk of labouring this, John
[a foolish thing for me to do, given that I have never used the objective in question]
Yes, you will almost certainly need to remove the 'bathtub' but for optimum results, I think the specified 'low power condenser' [or a home made equivalent] would be beneficial. ... The trick, as ever, being to put only 'useful' light into the lens.

MichaelG.

Yes I agree totally my friend - I see there's a large field condenser - presumably the one mentioned in the spec of the objective....

widefield condenser.JPG (12.54 KiB) Viewed 10334 times

Needless to say I've had a look online for said beastie but without luck so-far. I'll come across one somewhere and for certain I'll buy it!

Thanks for the heads-up Michael

[Perl]

Hi

Its a special condenser to this objective


Pär

[MichaelG.]

Its a special condenser to this objective

Excellent !!
Thanks for posting the photo.
Do you know [even approximately] the focal length?

MichaelG.

[zzffnn]

John B,

If you do buy such a specialized condenser, make sure you can return it for refund, if you don't consider it worthwhile after testing.

Such condenser may provide slightly better transmitted imaging.

But don't forget that many camera lenses outperform microscope objective at 1x-2x magnification, by a good margin. Someone compared a Mitutoyo 2x apo objective with a camera lens (don't remember which one, but it is much cheaper than the objective) before and concluded that camera lens performed better at 2x. I don't remember the specifics, but you probably should not expect too much from such a vintage Leitz achromat or pay too much for it.

[MicroBob]

As far as I know the overall image information is much higher in a low power objective than in a high power objective. For an objective like this here you would probably need a 50 mp camera to record all information. So it doesn't hurt much if you sacrifice 50% for a better depth of field. Apart from this: When you remove the condensor to light the whole image area you lose the condensor diaphragm and have no way left to control contrast. This lens is probably just great.

[zzffnn]

John B's Leitz scope has field diaphragm and that objective has iris to control glare. At NA 0.04 (a very low angle of light), is a condenser that much useful?

Please see how to calculate F/# aperture number from NA or vise versa, from Edmund Optics and a forum thread:

https://www.edmundoptics.com/resources/ ... e-setting/

http://www.photomacrography.net/forum/v ... +effective

A NA 0.04 microscope objective provides about F/12.5 as effective aperture at 1x on-sensor magnification.

A F/4 macro lens provides about F/8 as effective aperture at 1x on-sensor magnification. A F/2.8 macro lens provides effective F/5.6.That is theoretically a bit better than the microscope objective, with or without condenser. That is why many consider camera macro lenses better than microscope objectives at 1x -2x magnification, for reflected light macro at least.

Many microscopist use 1x or 2x objectives for convenience, not for image quality. So I myself may not want to spend $60 on a condenser for 1x objective to improve its image quality, when $60 can buy a pretty decent F/2.8 macro lens (such as a Schneider Componon S 50mm F/2.8). It is jus me though and your mileage may vary.

Also, I am guessing:
Iris 1x objective may be a design compromise between transmitted light and reflected light (forensic bullet analysis), while those (relatively) high NA 1x (NA 0.05) without iris may be optimized for transmitted light (pathology slides).

Coating is important for reducing glare and enhance contrast as well and its quality varies among lenses, older lenses tend to have less advanced coating (some have none). Those lenses designed for transmitted light theoretically should tolerate glare better than those designed for reflected light.

[mrsonchus]

Hi all and thanks for so many interesting ideas. I think zz' has hit-the-nail-on-the-head for my application - the convenience is the key for me - my microscopy as many folk know is for my prepared slides, permanently (resinous medium) mounted under cover-slip and imaged with transmitted light.

My set up is the permanently-mounted Canon 1200D atop the leitz photo-port and intermediate optic (a x10 Leitz photo-eyepiece and the 0.32x Leitz optic that is above it in the photo-tube assembly. Tethered shooting with Laptop and Canon software.

This is such a convenient setup with the need only to turn the nosepiece onto another objective, or even slip my other Leitz nosepiece in with my immersion objectives on-board. I really would hate to have to use a macro-fitted camera just for these full-section shots...

The use for such a x1 is for me a matter of identification and cataloguing of individual slide contents as a whole-section image. For actual slide-surfing and close study I move straight to the higher magnifications, mainly x10 - 25 for morphological snapshots then x40 upwards and into oil-immersion high n.a. for the histological and intra-cellular work such as mitotic figures...

My x4 Pl Fl 0.14 gives superb images without the condenser in place - I'm hoping the x1 will do the same, especially if I can use it's iris to control unwanted light and flare/contrast drop from such. We'll soon find out! My fingers are now crossed.....

Thanks again folks, some really interesting aspects being mooted here also.

John B.

[mrsonchus]

Hi all - it arrived this morning!
It doesn't work!

No fault with the objective, which is truly immaculate with a totally smooth iris - in lovely crystal-clear condition in fact.

But, as suspected the field of the objective is so large that the circle of light from the condenser or without condenser the field iris on the Orthoplan's light port cannot come close to filling the field. The result is a (very) vignetted field of view....

Tried with top condenser lens swung out - no good, with condenser removed - no good, with condenser top-lens swung in (you never know) - no good. I couldn't get the Orthoplan's stage to lower enough to focus with it either - I had to put the slide across the (empty) condenser-holder's arms and use this as an 'extra low-down' stage if you like, to enable focus.

I tried it in my SM-LUX which just about had the travel to focus the slide - 3cm below the lowest point of the objective is where it focused. Still, this seems just a combination of the maximum travel of the Orthoplan needing to be lowered a little, and the fact that this objective is quite long for a low power objective, by virtue of it's built-in iris mechanism. It is for example considerably longer than the x4 objective which has no iris assembly on-board.

Tried just about every combination of 'scope and condenser etc but no joy. Knowing how superb the Leitz 'scopes are it seems clear that the answer would be the fabled 'large-field condenser' which I suspect will be very hard to find indeed.

So, I've contacted the fellow from whom I bough it to see how he feels about a return - having made it perfectly clear that the objective is faultless - in fact it's immaculate. So, I'll wait to see what happens and put it down to experience!

I don't suppose anyone knows where I can buy a wide-field condenser for the Orthoplan?

I have a thought that a simple 'bull'seye' lens swung in below the condenser ala the Abbe condensers may do the trick though. If I end-up keeping it I'll see what I can do while I wait and search forlornly for a wide field condenser....

Thanks for all the input chaps!

[zzffnn]

John B,

Have you tried a large enough mirror placed at 45 degrees and a well diffused light source, without condenser?

Or place a diffusion material (large frosted glass or Vellum paper or office paper) on condenser mount, change mount height, remove condenser, and use scope light source?

I remember my Nikon 1x NA 0.03 iris objective works with transmitted light, though cannot remember exactly how I got it to work (it may be a simple trick), as I did it a while back. Yes, 1x objectives, even though designed to be used on biological stage, usually have longer than usual working distance and may not work on small scopes (whose stage travel is limited).

[charlie g]

Congrats on your sure to be used 1X objective, Mr.Sonchas! I love my Nikon Plan 2X/ 0.05 160/- , I use it all the time with algae field collected and fresh-observed 'in toto', or larger worms, leaches, fish fry, insects, etc. .

This wonderful thread hosts such great microscopy experienced members comments, thank you John B./ Mr.Sonchas for this posting.

With certain stands I have, the top lens of the substage condenser 'swings out of the light path' for use of these low power (near macro optics) objectives. My Nikon Labophot stand simply permits lowering the condenser on it's rack...for the 2X objective to function...ahh...but I always pined for a Plan-apo low mag objective..but the eBay prices stop me from such an acquisition!

My only suggestion, Mr.Sonchas, is see if your stand permits dark field illumination with your 1X objective with an iris. Play with that objectives iris adjust, while using DF illumination...may obtain a pleasant 'sweet spot' of DF illumination. Terrific microscopy you kindly share with us...bravo to your newest optic! Charlie guevara

[MichaelG.]

Tried just about every combination of 'scope and condenser etc but no joy. Knowing how superb the Leitz 'scopes are it seems clear that the answer would be the fabled 'large-field condenser' which I suspect will be very hard to find indeed.

I feel your pain, John

Page 15 of the Ortholux II manual http://www.science-info.net/docs/leitz/ ... lux_II.pdf
contains this useful advice:
.

http://www.science-info.net/docs/leitz/Leitz_Ortholux_II.pdf

IMG_1634.JPG (312.52 KiB) Viewed 10207 times

.
If only we knew the focal length of the fabled 'large-field condenser' I'm sure it would be a relatively simple matter to find a substitute lens.

With best wishes
MichaelG.

[mrsonchus]

If only we knew the focal length of the fabled 'large-field condenser' I'm sure it would be a relatively simple matter to find a substitute lens.

With best wishes
MichaelG.

Thanks Michael - that's a very handy piece of info - It's always worth perusing manuals as they often contain 'general' information applicable to other 'scopes. I, in my daftness, didn't think to look at the Orthoplan's manual - it's probably in there too...

Well, I'm waiting to hear re a return, my Darling Wife says I should keep it and wait for the condenser to appear....
The more I look at the LFC image the more it looks like a simple lens as you say...

I'll have a ponder today - this morning I'm just about to take some tissue (Haworthia succulent leaf parts) out of infiltration and to embed a nice new set of wax-blocks.... (probably have a few images to share later although they're not the most interesting tissue - I'm 'doing' a set of comparisons between 2 different Haworthias, the so-called 'Christmas Cactus' (I believe in the U.S. it may be known as the 'Fall Cactus') and the always-awkward Aloe.vera) - should be interesting...

Thanks again Michael

[Charles]

There is an article in Micscapes on using the Zeiss 1X and the lighting which was required.
http://www.microscopy-uk.org.uk/mag/ind ... power.html

[einman]

I'm catching up on posts. Forgive me if this has been mentioned but Leitz has a 1.6X objective in addition to the 2.5X you recently purchased. I have owned several and recently sold all but my last one. It is a fine objective and could be a worthy addition to your collection. Mine is not for sale though!!

[mrsonchus]

I'm catching up on posts. Forgive me if this has been mentioned but Leitz has a 1.6X objective in addition to the 2.5X you recently purchased. I have owned several and recently sold all but my last one. It is a fine objective and could be a worthy addition to your collection. Mine is not for sale though!!

Argghhhhh... You know you don't need it my friend.... just imagine the extra space that selling this to me would give you!

A question - why - oh why - is there nearly always a dratted 'darker-side' and of course 'lighter-side' to images stitched from the ax4 or lower objectives, with or without condenser?

Without condenser the x2.5 shows only the tiniest hint of this phenomenon but still it's there! I've tried a different objective position in the same nosepiece, my other nosepiece, condenser in/out, adjustments to the lamp-housing, swing-in lens in 'scope's base swung in/out, turning the camera, exposure settings, - I'm beginning to suspect that it's linked to the nature of a digital camera's image acquisition - I've also tried RAW image's to see if the camera's mpg creation routines may be a factor - no clues thus far! Any ideas folks?