LWD objective on 0.18 cover slip slide.

[Kionka]

Hi,
I just started and made a silly problem. Instead of buying a finite 20x 160/0.17 I bought a finite LPL LWD 25x 160/1.5. What is the compromise of using this instead of the one for 0.17 cover slip? My intention is using it to capture crystal on slide, watch some dyed slide or slide without cover slip.

[mrsonchus]

Easily-done! I suspect that one's for inverted microscopy - hence the LWD and the thick cover-slip (petri dish bottom)...
Personally I'd re-list that one and crack on with looking for the correct one - you'll only ever be compromising with this one, better to start with the right one/s. Just a case of experience old chap, I've lost count of the mistakes I've made as I've developed my microscopy, as have we all I think.

[MicroBob]

Hi,
in theory the 0,17mm instead of 1,5mm glass layer will introduce abberations to some extent. But as you already have it I would suggest to just compare it with the weaker and stronger objectives you have an see how well it performs. I would also look for parfocality and especially check for image quality in the plane of sharpness and above and below. You can then compare to the image of the slide with cover slip down and see whether you find much difference. The objective might work well. Zeiss 25:1 160mm objectives are not as common as 10:1 and 40:1 so you might have to look for one for a while.

Bob

[photomicro]

Hi,
I just started and made a silly problem. Instead of buying a finite 20x 160/0.17 I bought a finite LPL LWD 25x 160/1.5. What is the compromise of using this instead of the one for 0.17 cover slip? My intention is using it to capture crystal on slide, watch some dyed slide or slide without cover slip.

so have you actually tried it to see how good/bad the image is?

Do so, then put the slide upside down on your stage, and things should improve markedly.

I realise this is a faff if you were to do it each time, and would require adjustment from your other lenses, but it might let you see if the performance is so bad it isn't useable.

[Kionka]

Thanks a lot, I will get the correct 20x or 25x and put this on sale.

I still have a question. I got an eyepiece thanks to mrsonchus. It is parfocal when I look through the photo eyepiece and the binocular, however when I put my camera with the adapter on it, it will be out of focus and the edges are extremely unsharp.



Through eyepiece



Through photo eyepiece



Camera through photo eyepiece without 13mm to sensor stacking



Camera through photo eyepiece with 13mm to sensor stacking



Setup with stacking.
I use a K mount macro tube connects to k mount - e mount adapter.

[Scarodactyl]

Do you have a lens between the camera and eyepiece? Most Zeiss setups of this era would have used one.

[MicroBob]

If the eyepice is parfocal when sitting in the photo port it won't project an image on you sensor up there. When you lift it up ca. 10mm you might get parfocality.

Bob

[Kionka]

If the eyepice is parfocal when sitting in the photo port it won't project an image on you sensor up there. When you lift it up ca. 10mm you might get parfocality.

Bob

I raised it about 5mm and got these, look better but I think I expected more from it.

with 10x objective


with 2.5x objective

Do you have a lens between the camera and eyepiece? Most Zeiss setups of this era would have used one.

I use a meiji 2.5x photo eyepiece.

[MicroBob]

Is that made with a 2,5:1 objective? And is it a plan objective?

[Kionka]

Is that made with a 2,5:1 objective? And is it a plan objective?

Yeah, it is a Zeiss plan 2.5:1 objective with Meiji 2.5 photo eyepiece.

[MicroBob]

The Plan 2,5 is quite a nice objective, see here: https://www.mikroskopie-forum.de/index. ... ic=39220.0
The image in the link is better than I would have thought possible with a single shot and this objective. But this doesn't happen by itself. The usual condensers are not really optimized for this low magnification and big object area. You might get a better image when lowering the condenser or putting a paper tissue or other diffuasor on top of the condenser top lens. You might also remove the top lens or the complete condenser. Then a thin section is better for use with these low power objectives.

[Kionka]

The Plan 2,5 is quite a nice objective, see here: https://www.mikroskopie-forum.de/index. ... ic=39220.0
The image in the link is better than I would have thought possible with a single shot and this objective. But this doesn't happen by itself. The usual condensers are not really optimized for this low magnification and big object area. You might get a better image when lowering the condenser or putting a paper tissue or other diffuasor on top of the condenser top lens. You might also remove the top lens or the complete condenser. Then a thin section is better for use with these low power objectives.

My condenser has a flip top and according to the manual it can be used for 2.5x.
I just tried to compare the 2.5x with no condenser and with it.


Without the condenser



With the condenser and no top element.

The funny thing is when looking at the binocular, the condenser gives better image than without it.

[Scarodactyl]

I use a meiji 2.5x photo eyepiece.

Oh, there's your problem. I don't know what compensation meiji uses in their scopes, but Zeiss used about the strongest compensations of their era. The correct Zeiss eyepiece is vital to getting good photos since they are delicately matched with thr objectives to make a complete optical system.

[MicroBob]

What puzzles me: Why do the images have a black border? To me this looks as if the section is nat fully illuminated.

Bob

[Kionka]

I use a meiji 2.5x photo eyepiece.

Oh, there's your problem. I don't know what compensation meiji uses in their scopes, but Zeiss used about the strongest compensations of their era. The correct Zeiss eyepiece is vital to getting good photos since they are delicately matched with thr objectives to make a complete optical system.

Or maybe I am too picky on this.

What puzzles me: Why do the images have a black border? To me this looks as if the section is nat fully illuminated.

Bob

The black borders are because of cross polarization Bob.

[MicroBob]

The black borders are because of cross polarization Bob.

Okay, I didn'T have this in mind. To check image quality I think plain bright field is better.