Stated magnification versus real magnification

Es gibt 56 Antworten in diesem Thema, welches 10.696 mal aufgerufen wurde. Der letzte Beitrag () ist von Steve_mt.

1. offizieller Beitrag

    I have bought a x 1000 oil immersion objective (Karl-Zeiss) but when I calibrated the lens (stage micrometer / ocular eyepiece micrometer technique) I did not get a 1:1um (mathematically should be so) but 1 real um occupied 1.17um on the ocular viewed image, or in other words 1um in the viewed ocular is less than 1um. That means the viewed magnification is not x1000 (if so, then 1um in the stage would be equivalent to 1um in the optical) but less, around x 800. Have you also the same issue and thought?

    • Offizieller Beitrag

    Hello, Steve!


    That's odd.
    Maybe there's a problem with the ocular lenses? If the fabricate of those (or of the microscope itself) ist different, there may be slight differences.
    Thus i did not observe such a problem when putting a Zeiss 1000x objective to another microscope...



    LG; Pablo.

    Hi there,


    just do a bit physics. The nominal magnification is valid for an exactly positioned object and environment. Whenever you move the object here and there, or adjust the ocular to your eyes - the magnification is also slightly changed. This is unavoidable. And yes, the different refraction index of oil in comparison to air contributes as well.

    Much appreciated you checked this!


    Best regards,

    Bernd

    Hello Steve,

    for me the big difference in magnification looks strange.

    I do not know, which microscope you are using.

    Are you sure, that your binocular or trinocular tube does have magnicfication 1x ? Sometimes they have a higher magncification factor, perhaps 1,2x, that could explain bigger image in the ocular.

    Best regards

    Günter

    Glaube denen, die die Wahrheit suchen, und zweifle an denen, die sie gefunden haben. (A. Gide)

    Gefällt mir 1

    Hello Steve,


    that is the objective from FluorescensMicroscops.com, isn't it?


    You have an infinity objective, and unlike the 160 tube length objectives the infinity ones often do only fit in the very microscope version it was made for. So you can normally not use an infinity objective from Zeiss in a microscope from Olympus, just as an example. What microscope do you have and which tube length does it have? I bought a Zeiss 80x infinity objectiv for dry use and tried it on my Olympus BX40 - no chance, doesn't work, bad luck ......

    Another idea is that this is probably a objective for fluorescens microscopy and may be it works only properly with a fluorescens equipement?


    Oil with wrong refraction index will result in unsharp view, but doen't affect the viewed magnification (at least not that much), and neither does a movement of the object.


    all the best,

    Andreas

    But then the 630x objective at same conditions (except not oil) does not suffer from any discrepancy.


    Hi Andreas, I bought it from ebay and there is one like it here:

    Zeiss Plan-NEOFLUAR 100x/1.30 Oil Objective


    I was told infinity objectives made by Zeiss should work on Zeiss microscopes so I had a budget and this objective looked really good. However I am a bit disappointed with the resolution, and often the lens has to touch the cover slip to have focus. I don't know if, If it does work well for transmitted light application.


    Maybe u r right re used ONLY for fluorescent microscopes, but websites selling the exact obj are saying that it could be used both for light and florescent applications ! As far as I know, such a specific lens should be colour coded . where black it means for transmitted light





    Zeiss Plan-NEOFLUAR 100x/1.30 Oil Objective



    I also have this objective : Zeiss Plan Neofluar 100x/1.30 Oil Pol Microscope Objective Lens 440483 for sale online | eBay

    Dear Steve,


    my knowledge about this optical problems is limited. But I will transfer this problem to the microscopy forum, which usually provides very good help. It usually is in German language, but I will send you the results.


    all the best,

    Andreas

    Hallo,


    ich glaube nicht so recht daran, dass das Objektiv eine so deutliche Veränderung im Abbildungsmaßstab liefert.

    - War es vorher wirklich 1:1 ablesbar?

    - Ist das Messokular das gleiche wie vorher?

    - Ist die Messskala im Okular die gleiche? (Es gibt so viele verschiedene Skalen)

    - Ist die Strichplatte im Messokular verrutscht?

    - Objektmikrometer richtig herum eingelegt?

    Am einfachsten ist es, die beiden 100er Objektive nebeneinander einzuschrauben und direkt zu vergleichen.


    Freundliche Grüße

    Peter

    Hi there,


    I don't really believe that the lens delivers such a clear change in the image scale.

    - Was it really readable 1: 1 before?

    No, always 1:1.17 (oil mount)


    - Is the measuring eyepiece the same as before?

    Eyepiece original of microscope (Zeiss Axioscop 20) but reticule different.


    - Is the measuring scale in the eyepiece the same? (There are so many different scales)

    yes


    - Has the graticule slipped in the measuring eyepiece?

    No


    - Is the microscope micrometer inserted the right way round?

    \yes, if not the numbers of the micrometer will be inverted and I would know


    The easiest way is to screw in the two 100 lenses side by side and compare them directly.



    Peter, maybe you are misinformed, but the lens always gave this 1:1.17, that is, it was not like it was giving 1:1 and now all of a sudden 1.1.17. If I remember the previous x100 objective did the same.


    regards

    Peter



    I wonder if you guys have your x100 objective giving 1:1 or 1:>1? when using oil (that is you put a drop of oil on stage micrometer)

    Thanks - but have I posted in the microscopy section already? I start thinking what happens without oil immersion ...and also if users here calibrate the magnification (for measuring) compensated for oil immersion! ! !

    Hallo Steve,


    ich glaube, du hast die falsche Strichplatte im Okular (reticule different). Es gibt viele verschiedene!

    Ich würde direkt bei Zeiss nachfragen, welche Strichplatte die empfehlen und ob die Umrechnung beim 100er Objektiv 1:1 ist.


    Deine Okulare sind 10x?


    Freundliche Grüße

    Peter


    PS: Oder du kaufst dir gleich ein "richtiges Mikroskop" von Olympus.:saint:

    Bei meinem Mikroskop ist das mit 1:1 Standard.

    Es kann auch ein wenig variieren (+- 2%) aber nicht 17%.

    Hello Steve,


    I misunderstood and was thinking your former 100x objective gave 1:1 and now the new one is 1:1,7.

    So this is of course another kind of problem.


    I second Peters opinion that the problem is the measuring scale in the eye piece.


    You should have the same unusual multiplication factors also in the other magnifications, means 1:4,25 with the 40x objective (instead of 1:2,5) and 1:17 with the 10x objective (instead of 1:10) - correct?


    all the best,

    Andreas

    this morning tried the calibration without oil and I got 96-97 units for 100um (everything same setup but no oil on stage). The focusing and sharpness was quite good actually! That makes 100/97 = 1:1.04 which is a good match.


    Replies:

    I second Peters opinion that the problem is the measuring scale in the eye piece. >> Same eyepiece reticule for all objectives (which gives expected values)


    You should have the same unusual multiplication factors also in the other magnifications, means 1:4,25 with the 40x objective (instead of 1:2,5) and 1:17 with the 10x objective (instead of 1:10) - correct? >>> For the other 'air' objectivesI get a close value to the expected magnification.


    Your eyepieces are 10x?

    Yes E-Pl 10

    Or you can buy a "real microscope" from Olympus right away.:saint:

    You need real money too!

    Would be nice if someone can test the same procedure and calibrate the measurements with oil and without oil for the x100 objective and see if there are same results. Because if one measures spores under oil immersion and applies a 1:1 scale, there might be some 15% error in the measurements!!!! --- or is it just me here with this anomaly ?!?!

    Hi Steve, the magnification of immersion objectives is always stated with oil, coz it is designed to be used with, coz oil allows higher magnification. What n has your oil? n ~1,5.

    Best regards, Bernd

    Hi Steve,

    The objective cleary states 'oil' on it's label, so it should be used with oil only. The objective also states planar, but your photos are really distorted.


    the ebay link you posted shows two different objectives, one for infinite optics and one for 160mm tubes. best copy the full label of one correct objective (probably labelling an infinite sign) and of the new one - the important part is not visible on the picture.

    The Axioscope 20 should be infinite, is it?


    Wolfgang

    This is the one I am testing right now:


    ZEISS Plan-NeoFluar

    100x / 1,30 Oil

    1018-595 (1066-987)


    on the other side


    ZEISS Plan-NeoFluar

    100x / 1,30 Oil

    ∞ 0,17


    I took photos by digital camera from the eyepiece.

    The other old x100 oil eyepiece behaves the same. In oil mount 100um gives 85 reticule units and was shown in the photo.

    This is a Zeiss NeoFluar 100\ 1.30 Oel 160\- code 48600960


    Please not that my Microscope Is AxioLAB RE