Wild M3Z Type S and Kombistereo

[Rorschach]

Hello,

I would need to swap a Wild M3Z optics body from a Type S carrier (the one that provides axial option for photography) to a Wild Kombistereo carrier (the one that switches between a normal stereo objective and a Leitz compound objective). However, I can't see any apparent way how to detach the optics body from the carrier. Has anyone done this or a swap between the basic M3 series carrier?

[PeteM]

Some time ago, I swapped a type S carrier from an M3B to an M3Z. Recollection is that it was straightforward once I got past an initial hesitation. There are screws top and bottom. The knobs have screws and come off from the sides.

I'd just start working your way in, snapping a photo or two along the way so the right screws are put back in place. While inside, if there's the slightest hesitation in the zoom, you might re-lube the zoom guide bars.

Riku - it should be wonderful to have a Kombistereo . . . and someone else is likely to lust after your S sliding carrier.

[Rorschach]

Well, I tried but this is as far as I could get.

The cluster of screws in this first image seems a bit daunting. I have no idea which of these could/should be unscrewed to get further without causing problems.

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[PeteM]

Riku, I don't have experience with the Kombistereo you're showing. For the S-type slider you already have and want to remove, I recall small screws (visible by removing the objective and sliding the S carrier to one side or the other) that remove the M3Z zoom body from the S-type carrier.

On your Kombistereo, I'd assume that the objective carrier also removes from the bottom of the M3Z zoom body.

[Scarodactyl]

You absolutely do not need to remove the shell. What Pete said there sounds familiar, I have installed one in an s carrier before.

[Rorschach]

Thanks for the tips guys! Like you said, it was an easy and straight forward job. Now swapped. As I expected, Kombistereo really does not work with a 0.5x achromat stereo lens. The compound lens, which is a Leitz Plan L 25x/0.40 infinity, is "antifocal" with that, you have to scroll the focus for ages when switching between the two. I think I'll try the 1.5x achromat which has a lot smaller working distance. Might be a good combo.

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[Rorschach]

Update: the 1.5x achromat is not a good match. It has too short a working distance: when in focus, the compound lens front element comes extremely close to the subject! Definitely not good, and is not close to parfocal either.

The best match is a standard 1x achromat which is close to parfocal. It also leaves the compound lens high enough so that it clears the edges of a standard petri dish when one changes between the two objectives, a very important practicality!

The image produced by the compound lens only fills the image circle at zoom setting of about 16x and higher. At the lowest mag it only fills the center of image circle. I wonder whether a plan fluorite or plan apo long working distance lens exists from Leitz? That might be a very nice upgrade here.

@Petem Yes, I already have a buyer for the Type S carrier, which is why the swap. The carrier goes on a complete M3Z setup to be sold in a few weeks. I am able to let the Type S carrier go because I am in the process of buying a similar, but custom, part for my Wild M10 from Scaro here

[Scarodactyl]

Is thr spacer for the objective permanently affixed? I'd be tempted to pick up a longer parfocal objective with a larger field of view like this RMS mitutoyo clone from Seiwa https://www.ebay.com/itm/175059560631
Wild stereos are essentially non-compensating so a neutrally corrected objective will probably give the best results.

[Rorschach]

Is thr spacer for the objective permanently affixed? I'd be tempted to pick up a longer parfocal objective with a larger field of view like this RMS mitutoyo clone from Seiwa https://www.ebay.com/itm/175059560631
Wild stereos are essentially non-compensating so a neutrally corrected objective will probably give the best results.

It looks to be permanently affixed. The objective can be screwed off, of course. The spacer has an adjustment ring that allows about 2-3mm of parfocality fine tuning.

I have yet to do a more proper test but it seems that the two objectives are not perfectly parcentered. The extreme difference in mag makes it a bit hard to know how far off they are. Though I remember reading somewhere that on the Kombistereo, a compound lens will not quite give the mag it says on the tin. Something to do with the other optics in there between the objective and the zoom I suppose. So I guess what I am getting is not quite 250x but nevertheless a lot more than the 40x the stereo side gives as maximum.

Edit: after some googling, I found the exact reference posted on a German microscopy forum. So, in fact, it's a lot more than 250x, it's 400x when the zoom is at the max Here's a screenshot of it:

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Edit2: The table also confirms what I already saw when testing: Wild did not consider mags below zoom position 16x usable with the compound lens.

[Scarodactyl]

That all tracks. The reference focal length of the m3z is 100mm, so 2x is going to give you a 200mm tube lens focal length.
Incidentally I have an optem 10x/0.45 HR objective which Leica rebadged for use on their macro/stereo fluorescence setups (z series macrofluo and the fluocombi, the descendant of the stereokombi). It is a good pick because it has limited field coverage at nominal magnification but a high enough NA to stand up to higher magnifications. It would need an m26 to rms adapter but might be a good fit. Mine has a couple chips on the front glass but performs well--maybe we can bundle it with the m10 accessory at a good price.

[Rorschach]

That all tracks. The reference focal length of the m3z is 100mm, so 2x is going to give you a 200mm tube lens focal length.
Incidentally I have an optem 10x/0.45 HR objective which Leica rebadged for use on their macro/stereo fluorescence setups (z series macrofluo and the fluocombi, the descendant of the stereokombi). It is a good pick because it has limited field coverage at nominal magnification but a high enough NA to stand up to higher magnifications. It would need an m26 to rms adapter but might be a good fit. Mine has a couple chips on the front glass but performs well--maybe we can bundle it with the m10 accessory at a good price.

So the Optem would have the same limited field coverage at low mags? What would it's working distance be when the m26 to RMS adapter is accounted for? Being close to parfocal and able to clear petri dish edges are of interest. It is an intriguing option though. Also depends somewhat on the value

[Scarodactyl]

Yeah, the limited field coverage comes down to entrance pupil shenanigans iirc (huge lenses being needed to counteract that). Working distance is 19mm, not terrible for the n.a. Parfocal distance on its own is 95mm, I am not sure which m3 objective would be closest but it's much longer than the presumably 45mm of the leitz.