B&L Stereozoom Photography ?

[Sliding Focus]

The camera adapter I believe is simply a periscope that slides over the left optical path or, when not in use, rests between the optical paths. If the mirrors have already been checked out there's not much else with that device.

That is also my understanding. I've inspected the optics with a flashlight and everything looks clean and in good condition (one of the optical surfaces has some streaks or scratches, but nothing that looks consequential). However, besides taking test photos, I don't know how I'd tell if something was out of alignment or otherwise put together the wrong way—and I'm not sure how best to interpret what I see in the test photos that I've made. Do you know of anything else I could try doing or looking for to tell if the camera adapter might need to be adjusted in some way?

Maybe some kind of tube length mismatch with the camera? Maybe a reduction lens is warranted? Not sure.

I can see the blurriness (albeit in less detail) when I put a viewing eyepiece into the trinocular tube and look through it with my eyes, so I don't think that the issue has to do with the tube length or the optics that pick up the intermediate image (though I could be wrong!). FWIW, I've been using a Nikon CF PL 2.5x photo eyepiece to project the image onto my camera's sensor, which Scarodactyl reported to work well in this thread: viewtopic.php?t=7510. And, I've also tried using my B&L 31-15-71 10x W.F. Stereo eyepiece on a spacer (to make it work like a projective eyepiece) and tried using the afocal method (using the B&L eyepiece and a Tokina 35mm macro lens), but I've gotten more or less identical results each way. Before each test, I used the B&L eyepiece to parfocal the camera adapter by eye before attaching the camera to the microscope. For the Nikon 2.5x eyepiece and the B&L eyepiece on a spacer, I then parfocaled the camera by adjusting its distance from the eyepiece using a helicoid extension tube (not by touching the focus adjustments on the microscope stand or camera adapter).

[BramHuntingNematodes]

You say you can see it when looking through the eyepiece, a difference between the camera adapter and the regular eyetube. This brings me back to those mirrors. You conducted a visual inspection and it seems to look ok, but on the other hand there is detectable blurriness. Can you ask I. Miller about this? They took a look at it, presumably they know that model in and out.

[Sliding Focus]

You say you can see it when looking through the eyepiece, a difference between the camera adapter and the regular eyetube. This brings me back to those mirrors. You conducted a visual inspection and it seems to look ok, but on the other hand there is detectable blurriness. Can you ask I. Miller about this? They took a look at it, presumably they know that model in and out.

I could talk to I. Miller. I'm hesitant to because I've been a bit unhappy with my experiences with them, so I'd rather fix (or at least diagnose) the issue myself if possible, but they probably are the most qualified people (and certainly are more qualified than me!).

I also found a shop more local to me that I've been thinking I might reach out to if I can't get help on these forums. It's probably a long shot, but you (or anyone) wouldn't happen to have had or heard about personal experiences dealing with Micro-Optical Methods in Albany, NY, would you?

[MichaelG.]

OK, I spent some time over the weekend making test image series to illustrate the blurriness I am seeing. They are available in an album on my flickr account, here: https://flic.kr/s/aHsmS3KGg4. (Would it be better for me to link the images directly?) One series was shot using the Nikon CF PL 2.5x eyepiece, and the other using the afocal method (handheld, so quick and dirty) through the B&L 31-15-71 10x W.F. stereo eyepiece. Neither eyepiece was raised. […]

The test subject (the label on a packet of insect pins) isn't necessarily the best for illustrating the problem, but it is the most finely-detailed flat object I had on hand.

In both image series, there is obvious blurring at low magnifications that incrementally diminishes as the magnification approaches 7x. It is especially evident on the specular highlights. To me, the blurring looks like astigmatism, but it is much more severe than what I have seen in any of my camera lenses, and affects even the central portion of the image (astigmatism normally does not occur on-axis, but might if the optics were misaligned). This blurring is not visible through the light paths for viewing—the difference is night and day (I can share images if it would be helpful).

Scarodactyl—or anyone—have you seen this behavior before? […]

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It’s a month since you linked those images ... so I am very late commenting

Very broadly speaking, I think I see a combination of two problems:

• The resolution is not great [this may simply be down to the typically low Numerical Aperture of a stereoscope]

• There is considerable curvature-of-field; which appears to be worse at the lower magnifications [again, not particularly surprising with a zoom system]

Yes ... It would be very useful if you can provide some images taken via the ‘visual’ light path, because it might help localise the problem.

MichaelG.

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P.S. __ Just found this, which has some useful photos of the internals of a StereoZoom 7
https://www.eevblog.com/forum/testgear/ ... -teardown/

P.P.S. __ and this [which is rather neat]
http://transistor-man.com/bausch_lomb_m ... light.html

[BramHuntingNematodes]

The resolution of the SZ7 is excellent and should handily take unblurred pictures. Sliding focus has already noted an apparent difference when looking through the eyepiece versus the camera adapter.

[MichaelG.]

The resolution of the SZ7 is excellent and should handily take unblurred pictures. Sliding focus has already noted an apparent difference when looking through the eyepiece versus the camera adapter.

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Exactly, Bram ... That’s why I wrote:
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Yes ... It would be very useful if you can provide some images taken via the ‘visual’ light path, because it might help localise the problem.

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MichaelG.

[MichaelG.]

You enthusiasts probably know all about this, but it was new to me:
https://science.sciencemag.org/content/ ... matter.pdf
Nice StereoZoom 7 advert on p1 of the pdf

MichaelG.

[Scarodactyl]

Yeah, the sz7 tops out at 300 lp/mm at max zoom (600 with a 2x), which puts it ahead of scopes like the stemi 508. Not sure what the minimum is.
I'll try to do some tests of my own at some point a d report back.
Those old vintage ads are great, and provide the best info about release dates. While doing a deep dive I came across a reference to b&l presenting the "monozoom 4" at some conference in Germany back in the 70s. Apparently they were cooking on macroscopes even before Wild.

[BramHuntingNematodes]

That stand in the ad reminds me that one thing about the stereozooms is that often pick up minute vibrations. The fan on my fiber optic light, for instance, blurs the heck out of my view.

[MichaelG.]

I’ve found another interesting advert, on p20 of this pdf : https://science.sciencemag.org/content/ ... matter.pdf

Which, refreshingly, quotes resolution [confirming Scarodactyl’s number, at 70x]

... reduced copy here:
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ADB243E2-2514-4D9B-AFAB-E2E6EE52042C.jpeg (159.97 KiB) Viewed 10422 times

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MichaelG.

[jfiresto]

... Those old vintage ads are great, and provide the best info about release dates. While doing a deep dive I came across a reference to b&l presenting the "monozoom 4" at some conference in Germany back in the 70s. Apparently they were cooking on macroscopes even before Wild.

Wild's innovation was to create a "Binocular Microscope with Improved Monocular Photographic and Measuring Capability using [a] Movable Objective" (U.S. Patent 3,994,558 from 30 Nov. 1976, extending Swiss Patent CH 565379 from 4 July 1974) by "rotatable eccentric or slidable mounting means" – realized in the M7S and M3xS models, respectively.

[MichaelG.]

Another classic advert on p16 of this pdf : https://science.sciencemag.org/content/ ... matter.pdf

MichaelG.

[Sliding Focus]

Very broadly speaking, I think I see a combination of two problems:

• The resolution is not great [this may simply be down to the typically low Numerical Aperture of a stereoscope]

• There is considerable curvature-of-field; which appears to be worse at the lower magnifications [again, not particularly surprising with a zoom system]

Yes ... It would be very useful if you can provide some images taken via the ‘visual’ light path, because it might help localise the problem.

Thanks for your comments. I agree that the microscope's low resolution causes some blurring—there's no getting around diffraction!—but what I get through the camera adapter is clearly inferior to what I get through the normal light path for viewing, so there's something more than that going on. I also agree that the field appears not to be flat, but I'm not quite sure how to separate any field curvature that might be present from the effect of the tilted focal plane. It probably would have been a good idea for me to eliminate that effect by tilting the subject 5–7º to match the inclination of the light path.

After reviewing my images from last month, I can only seem to find a series shot through the "visual" light path using my 15x UWF eyepiece, not my 10x one (I thought I'd done both.) So, I think it'd make sense for me to shoot a new test series so that I can show you all a 1:1 comparison between the "visual" light path and the camera adapter. That'll also let me redo the test with the subject tilted. I'll make the time this weekend.

In the meantime, you can view the images through the "visual" light path and the 15x eyepiece here: https://flic.kr/s/aHsmSHJ1Yj. They aren't as good as they could be, but it at least is clear that these images don't show the streakiness I see in those made using the camera adapter. Compare, for example, the following two images:


"Visual" light path @ 2x, shot afocally through my 15x UWF eyepiece by Kendrick Fowler, on Flickr


Camera adapter @ 2x, made using my Nikon CF PL 2.5x eyepiece by Kendrick Fowler, on Flickr

If shooting through the camera adapter gave the same level of quality as I see in the top image, I'd be very happy with it. I wouldn't exactly call the resolution great, but I think it's about what the microscope is capable of, and it's adequate for my purposes. What I get out of the camera adapter, however, is the bottom image. It's a streaky mess, and that's not very useful. Of course, I can just shoot through the viewing eyepieces instead of the camera adapter (and sometimes do), but the camera adapter is more convenient, so I want to get it to match the viewing eyepieces if I can!

Yeah, the sz7 tops out at 300 lp/mm at max zoom (600 with a 2x), which puts it ahead of scopes like the stemi 508. Not sure what the minimum is.
I'll try to do some tests of my own at some point a d report back.

The resolution at 1x is specified as 70 lp/mm on-axis and 35 lp/mm at the edge of the field of view, according to this link: https://www.manualslib.com/manual/92685 ... e=5#manual.

I'm curious to see what your tests show! Thanks in advance for taking the time.

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Edit: Can you all see the images I embedded (or tried to embed) in this post? I can't, and I'm not sure if it's because I didn't embed them correctly or because my internet isn't happy right now. It looks like the URLs work, at least.

Edit 2: I fixed the embedded images.

[MichaelG.]

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Thanks for the post ...
I can see your linked images, but not the embedded ones

I look forward to seeing a full ‘comparison set’ taken using the 10x eyepiece in each light path.

MichaelG.

[MichaelG.]

The resolution at 1x is specified as 70 lp/mm on-axis and 35 lp/mm at the edge of the field of view, according to this link: https://www.manualslib.com/manual/92685 ... e=5#manual.

That seems realistic.

MichaelG.
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Edit: I note that the photo-port is not covered in that document.

[DonSchaeffer]

This may not be a popular suggestion. If you want to photograph opaque specimens at 40X or so, a decent digital microscope on a good stand does that very well. And they are cheap.

[MichaelG.]

[…] Camera adapter @ 2x, made using my Nikon CF PL 2.5x eyepiece

If shooting through the camera adapter gave the same level of quality as I see in the top image, I'd be very happy with it. I wouldn't exactly call the resolution great, but I think it's about what the microscope is capable of, and it's adequate for my purposes. What I get out of the camera adapter, however, is the bottom image. It's a streaky mess, and that's not very useful. Of course, I can just shoot through the viewing eyepieces instead of the camera adapter (and sometimes do), but the camera adapter is more convenient, so I want to get it to match the viewing eyepieces if I can!

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Here’s what I was trying to get-at when I mentioned localising the problem:

If I understand the advertising correctly, this ‘scope was optimised for photography [on large format, or on 35mm] using a specific 10x eyepiece ... and I can see no reason to assume that the Nikon CF PL 2.5x eyepiece is a viable alternative [it may in fact be a superb combination, but we need to understand what’s occurring]

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Implicitly — Using a 10x eyepiece

7F43084B-479E-4E3E-AA80-889CAD3DBF86.jpeg (169.72 KiB) Viewed 10363 times

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Implicitly — This one

0C02F948-9718-432B-84C2-6443DF309F61.jpeg (115.64 KiB) Viewed 10363 times

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MichaelG.

[BramHuntingNematodes]

I got a photo adapter from this era and B&L put a large barlow right before the bellows I don't have it in front of me but if I remember right the glass elements are like an inch inch and a quarter diameter.

[Sliding Focus]

I have uploaded the new test series to Flickr. Here is a comparison of the images through the camera adapter, the left eye tube, and the right eye tube:


SZ7 test image series by Kendrick Fowler, on Flickr

To give a sense of scale: the letter “P” visible in the photos made at 1x magnification is 1.2mm tall.

The collage above is not presented at full resolution (the full-res version is 430MB!). In case any of you wish to examine the images at their original resolution, they can be found at the following links:

Camera adapter: https://flic.kr/s/aHsmSKMfsA
Left light path: https://flic.kr/s/aHsmSKSdMX
Right light path: https://flic.kr/s/aHsmSKVer3

Here’s a description of my method for shooting the test image series:

Before shooting, I checked that the camera adapter and the left eye tube were parfocal. I made one set of photographs with the subject tilted slightly to match the inclination of the microscope’s left light path, and another with it tilted to match the inclination of the right light path (however, I may not have gotten the angles perfect). In both cases, I made one photograph at each whole magnification setting through each of the camera adapter, the left eye tube, and the right eye tube. All of the phtotos were made using the afocal method with a B&L 31-15-71 10x WF Stereo eyepiece and a DSLR with a 58mm f/2 lens set to f/8. The same eyepiece and the same exposure settings were used for each image. I hand-held the camera, as I have no way of attaching it to the microscope while using the afocal method (which is why the photos don't all line up perfectly). The photographs were shot in raw (CR2) format and converted to JPG in Lightroom Classic CC (LR) using LR’s “camera standard” color profile and default level of chroma noise reduction; no other adjustments (including sharpening) were applied.

And, here is what I see in the photographs:

• The images made through the camera adapter appear as I’ve previously described: those at 1x show a severe, streaky blurriness, which gradually diminishes as magnification is increased, and is virtually eliminated at 7x. The specular highlights are shaped like a cross or a star, which makes me think that the blurriness can be attributed to astigmatism.

• Images made through the left eye tube show reduced contrast in comparison with those made through the right eye tube, at least between 1–3x magnification. However, they are markedly less blurred than those made through the camera adapter, and it is not clear to me what (if any) aberrations might be present.

• The images made through the right eye tube show good contrast, with no obvious aberrations (unless you count the rings around some of the specular highlights, which are also present in the images made through the camera adapter and the left eye tube, and which look to me like a mix of Airy patterns and defocus—i.e. nothing that one wouldn’t expect to see).

The observation that images made through the left eye tube show less contrast than those through the right is new—it occurred to me while I was shooting the series that I haven’t compared photographs through both eye tubes before, so I added the set through the right eye tube. It would appear I should have thought to do that sooner! Some of the difference between the light paths is probably attributable to lighting differences due to parallax (or some other uncontrolled variable), but the difference at 1x magnification is great enough that I think that the left light path’s optics might not be performing up to par. If that’s the case, then it seems quite possible—and maybe likely—that there is nothing wrong with my camera adapter, and it is merely amplifying whatever issue might be present in the left light path. Of course, I don’t know enough about optics to say that for sure, and I can’t rule out the possibility that both the left light path and the camera adapter might have issues—nor do I have a clear idea about how I would do so. It also still seems possible that my microscope is perfectly fine and I’m doing something wrong, but I am not sure what that might be.

For whatever it’s worth, I do not perceive a meaningful difference in quality between the left and right light paths when looking through the microscope. As I’ve mentioned previously, however, I can see that the image through the camera adapter is blurred when I look through the trinocular tube with a viewing eyepiece.

What conclusions do you all draw from this new image series?

[Sliding Focus]

This may not be a popular suggestion. If you want to photograph opaque specimens at 40X or so, a decent digital microscope on a good stand does that very well. And they are cheap.

That is an interesting suggestion—thanks. My interest in shooting photos through my SZ7 is really a matter of wanting to make the most of what I already have, and I definitely understand that it’s far from the only (or best) way to make images at the magnifications we’re talking about. I’ve been thinking that, if I ever start needing to do photomacrography more than a few times a year, I’ll pick up a cheap finite microscope objective or a Laowa 25mm 2.5–5x macro lens to put in front of my camera, but I’ll keep a digital microscope in mind as an alternative too.

[Sliding Focus]

... and I can see no reason to assume that the Nikon CF PL 2.5x eyepiece is a viable alternative [it may in fact be a superb combination, but we need to understand what’s occurring]

My only reason to assume that the Nikon CF PL 2.5x eyepiece works well is that Scarodactyl said it does (here’s the link again: viewtopic.php?t=7510). I agree that it is necessary to rule out that eyepiece as a factor; while the tests I’ve done can’t do that entirely, I think that they show, at the very least, that the Nikon photo eyepiece is not the primary cause of my problems.

If I understand the advertising correctly, this ‘scope was optimised for photography [on large format, or on 35mm] using a specific 10x eyepiece

Between the manuals and ads I’ve seen (including the ones you shared), it’s my impression that B&L pushed their Integrated Camera System as being the “ideal” solution for photomacrography using the SZ7 and their other microscopes, and never recommended using an eyepiece in the trinocular tube at all. I haven’t read anything to suggest that B&L specifically advised against using an eyepiece in the trinocular tube, either—and as with the Nikon eyepiece, folks here have reported good experiences with that method—but the ad doesn't read to me as recommending any specific 10x eyepiece for that purpose.

BTW—and I hope you don't mind my pointing this out—the eyepieces depicted in that ad look to me like the cat. no. 31-05-67, not the 31-15-71. The 31-05-67 has a silver casing like the ones in the ad, while the 31-15-71 is black (though I don't know for sure that there aren't exceptions). As you point out, though, the 31-15-71 was also advertised for use on the SZ7.

[Scarodactyl]

My reasoning for the 2.5x: nikon eyepieces give lower magnification on b&l systems (reducing cropping a bit on aps-c) and it does minimal-if-any compensation, which should match the center of a b&l image nicely while cropping edges where the b&l eyepieces might do more. They're also cheap and easy to use. It is also important to bring up the fact that I had essentially no clue what I was doing. It isn't my recommendation now, a cheap ndpl 2x adapter does better from further informal testing and is a lot less precariously tall.

Someday I need to update that thread--it was mostly presented because I was excited to find anything that worked, vs the only other guide I'd seen where the results seemed less satisfactory (or vs spending a billion dollars on a new third party adapter). 3d printing makes a lot of my "clever" improvised mechanical assembly obsolete too, not that I am complaining. I did a lot of photography with my own sz7 before I got my wild m400, but that was done with my phone through the eyepiece (one hand to hold down the button for burst fire, one to twiddle the focus knob for fast photo stacks.)
I will say, with 15x uwf eyepieces I am always super impressed with the view in an sz7. It's always better than I remember and very pleasing even after coming back from using my z6 apo.

[hans]

Impressively comprehensive set of test images and your conclusions sound reasonable. This seems unlikely to me based on the images:

...nothing wrong with my camera adapter, and it is merely amplifying whatever issue might be present in the left light path.

I think more likely, as you mention:

...possibility that both the left light path and the camera adapter might have issues...

Have you tried this yet, eyepieces removed, shining flashlight and looking from both ends, to see if you can see any difference right vs. left:

You can illuminate the light path and look down it (careful not to dazzle your eyes) to see if anything looks wrong. That's probably easiest, it would have to be a dramatic problem with the mirror I would think.

[MichaelG.]

BTW—and I hope you don't mind my pointing this out—the eyepieces depicted in that ad look to me like the cat. no. 31-05-67, not the 31-15-71. The 31-05-67 has a silver casing like the ones in the ad, while the 31-15-71 is black (though I don't know for sure that there aren't exceptions). As you point out, though, the 31-15-71 was also advertised for use on the SZ7.

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I don’t mind in the slightest
... It’s your ‘scope and you know more about it than I ever will

I’m just trying to help with the investigative method.

Incidentally; the eyepiece diagram was clipped from the Leica StereoZoom Series Microscopes ‘Instruction Manual’ ... http://www.science-info.net/docs/leitz/ ... scopes.pdf

Keep up the good work
MichaelG

[MichaelG.]

Between the manuals and ads I’ve seen (including the ones you shared), it’s my impression that B&L pushed their Integrated Camera System as being the “ideal” solution for photomacrography using the SZ7 and their other microscopes, and never recommended using an eyepiece in the trinocular tube at all. I haven’t read anything to suggest that B&L specifically advised against using an eyepiece in the trinocular tube, either—and as with the Nikon eyepiece, folks here have reported good experiences with that method—but the ad doesn't read to me as recommending any specific 10x eyepiece for that purpose.

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Perhaps I was reading too much into it ... but the advert claiming the impressive resolution figure specifically mentioned a magnification of 70x, so I assumed that meant 7x on the objectives and 10x eyepieces.

I remain unsure whether that claim was ever meant to read-across to the photographic system.

MichaelG.

[Sliding Focus]

Impressively comprehensive set of test images and your conclusions sound reasonable. This seems unlikely to me based on the images:

...nothing wrong with my camera adapter, and it is merely amplifying whatever issue might be present in the left light path.

I think more likely, as you mention:

...possibility that both the left light path and the camera adapter might have issues...

Have you tried this yet, eyepieces removed, shining flashlight and looking from both ends, to see if you can see any difference right vs. left:

You can illuminate the light path and look down it (careful not to dazzle your eyes) to see if anything looks wrong. That's probably easiest, it would have to be a dramatic problem with the mirror I would think.

Thanks, and thanks for your impressions!

I have examined the power pod’s optics with a strong light, but haven’t described their condition in this thread. Here’s what I see:

• Looking down from the top (though the eye tubes), I see obvious (reflective) patches of delamination along the edges of several optical surfaces, but their appearance doesn’t change when I turn the zoom knob—and, more notably, those on the left side remain visible when I switch the camera adapter to the “in” position (the mirror slides in below them)—so I’m pretty sure that they are confined to the prisms and/or relay lenses. I also see some cloudiness when I shine a light in from below; it again looks to me like it’s confined to the prisms, but it’s dense enough that I can’t say for certain that there isn’t any cloudiness present on surfaces deeper inside the microscope. (I don’t know for sure, but suspect that the cloudiness is another symptom of the delamination.) The delamination is somewhat worse on the left side, but not dramatically so—still, it seems reasonable to me to speculate that it could contribute to the lower contrast evident in the photos taken through the left eye tube. It should not affect the performance of the camera adapter, however.

• Looking into the ‘scope from the bottom, the two lowest groups of optics (i.e. the fixed bottom group and the lower of the two groups that move when the zoom knob is turned) show some faint cloudiness—but much less intense than what I see looking in through the eye tubes, and nothing that strikes me as likely to be a cause for concern. The (fixed) bottom-most group on the left side also shows a very faint but clearly-defined band of a denser cloudiness along part of its edge—maybe some incipient delamination?—and there might be a similar, but smaller patch on the right side too (it’s hard to tell). I’d feel like a hypochondriac to worry about those areas of denser cloudiness, but they’re the only notable difference I see between the two sides.

• I don’t feel like I can get a good look at the upper of the groups that moves when the zoom knob is turned (though I probably could if I took off the camera adapter).

A few other details that may or may not be noteworthy:

• While using the microscope, I sometimes think I see the left eye momentarily go out of focus while I’m turning the zoom knob between ~1–3x magnification, especially if I turn the knob quickly. However, it immediately looks fine again when I stop turning the knob, so I might just be seeing things (so to speak).

• On all of the binoculars and microscopes I’ve ever used, I’ve left the diopter setting at 0 (occasionally I’ll feel like it’s off and change it to ±0.1–0.2, but always end up deciding I like 0 better within a few days). The SZ7, of course, does not have a diopter scale, but I just made some measurements, and I currently have the left eye tube screwed in ~1mm lower than the (fixed) right eye tube. As mentioned previously, I readjusted the diopter setting before I shot my test image series, so I see two possible conclusions here: either the “zero” diopter setting is not at the same position for both light paths (which may or may not suggest a flaw in the optics), or I screwed up when I readjusted the left eye tube (which indicates a flaw with me ). The focus in the left eye tube looks fine to me right now, but I might try readjusting it again later to see if I end up with a different setting.

• It’s probably not relevant, but I could have sworn that the right eye’s field of view used to wander very slightly—not enough to be a problem w.r.t. the ’scope’s usability, but noticeable if I paid close attention—but I can’t reproduce that phenomenon now.

[Sliding Focus]

Perhaps I was reading too much into it ... but the advert claiming the impressive resolution figure specifically mentioned a magnification of 70x, so I assumed that meant 7x on the objectives and 10x eyepieces.

I remain unsure whether that claim was ever meant to read-across to the photographic system.

I’m sure you’re right that they meant 7x at the objective + 10x eyepieces when they wrote 70x, but I think that they specified that number just because 10x eyepieces were (I assume) standard equipment. My understanding is that microscope manufacturers specify the objective’s ability to resolve detail on the subject, not to project detail in the image (like, e.g. camera manufacturers do). So, if you swapped in a pair of 15x eyepieces (for example), magnification at the highest zoom setting would increase to 105x, but the specified resolution would still be 300lp/mm. And, resolution on the subject would likewise be 300lp/mm at the 7x zoom setting with whatever apparatus one chose for photography, but the resolution of the final image (as measured on the film negative or camera sensor) would depend on the size at which it was projected (e.g. 100lp/mm if the image were enlarged 3x, or 30lp/mm if the image were enlarged 10x).

Someone please correct me if I’ve explained that wrong!

[Sliding Focus]

My reasoning for the 2.5x: nikon eyepieces give lower magnification on b&l systems (reducing cropping a bit on aps-c) and it does minimal-if-any compensation, which should match the center of a b&l image nicely while cropping edges where the b&l eyepieces might do more. They're also cheap and easy to use. It is also important to bring up the fact that I had essentially no clue what I was doing. It isn't my recommendation now, a cheap ndpl 2x adapter does better from further informal testing and is a lot less precariously tall.

Someday I need to update that thread--it was mostly presented because I was excited to find anything that worked, vs the only other guide I'd seen where the results seemed less satisfactory (or vs spending a billion dollars on a new third party adapter). 3d printing makes a lot of my "clever" improvised mechanical assembly obsolete too, not that I am complaining. I did a lot of photography with my own sz7 before I got my wild m400, but that was done with my phone through the eyepiece (one hand to hold down the button for burst fire, one to twiddle the focus knob for fast photo stacks.)
I will say, with 15x uwf eyepieces I am always super impressed with the view in an sz7. It's always better than I remember and very pleasing even after coming back from using my z6 apo.

I thought your solution was clever! And you know more about what you're doing than I do, but your reasoning about the Nikon eyepiece makes sense to me—and it at least has given me good results at 7x. It's interesting to hear that the NDPL 2x performs better, though—that is good information.

I definitely envy folks who get to use the high-end Leicas (I'm doing entomology work, and they're popular in the field), so it's nice to hear that you still find the SZ7 enjoyable when you have access to that kind of equipment! The 15x UWF eyepieces really do transform the experience.

[MichaelG.]

My understanding is that microscope manufacturers specify the objective’s ability to resolve detail on the subject, not to project detail in the image [...]

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My interpretation was different [but I am certainly not claiming to be right] ... I thought the 300 lppm related to the visual resolution at 70x and was therefore dependent upon the combined performance of the objective+eyepiece as a 'system'

I have seen no substantiating evidence for either view
... I will, of course report back if I find anything more technical than the Bausch & Lomb advertising.

MichaelG.

[hans]

How do you feel about disassembling, at least partially, for more careful inspection/cleaning? I am not sure what is involved (have an SZ7 but have not taken it apart yet) but it may be difficult to troubleshoot further without having a look inside. Seems like there are quite a few people on here familiar with the internals that could help and I have seen manuals and exploded-view parts diagrams posted before.