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Wild Heerbrugg M7A Microscope - any experience
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jfiresto:

--- Quote from: zkrx on September 07, 2021, 07:04:00 pm ---... I acquired an M7A (I think) approx. 2 years ago. It changed my life wrt SMD work. I've also just found a simple phototube adapter on the local used market for cheap.
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You have the best bits from two different microscopes: a top half with the binocular tubes from an M3 or older M7/M7A, and a bottom half with the objective, zoom and focusing mechanisms, from a later M7A. The tubes' diopter adjustments support a much wider choice of oculars. They would be one of the first things I would upgrade if you have not already.

The M3 monocular tube could be the oldest of all and was typically used to create a photo- and/or video-only microscope. What is its internal tube diameter? That will suggest what you will need for intermediate optics. The phototubes I am familiar with have either a 38mm I.D. or a trifle more than 30mm I.D.


--- Quote ---I'd like to attach a Nikon DSLR to it. ... Is your phototube splitter an original Wild? These look quite hard to find nowadays. Also, how did you fix your camera to the tube?
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What model Nikon? A DSLR can be a little tricky to add because of its long path from flange to sensor. My brother convinced me to use a mirror-less, micro four thirds camera. Its flange focal distance is short enough that a later Wild photo tube can project directly onto the sensor without a relay lens.

For the above pictures, I used a Wild 376788 photo tube, an optic-less D10NLC 38mm to c-mount adapter, a c-mount to µ4/3rds adapter and an Olympus E-PL7.


--- Quote ---... thanks for the heads up regarding the Barlow lens! I was looking for an affordable option....
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You are welcome. Keep in mind that the lens is a simple achromat, like the Wild/Leica original it copies, which softens the image approaching the edges. I am looking at adding an 0.4X plan-achromat meant for a Wild M8. It promises to keep things flat and sharp everywhere. I hope to get some time on a metal lathe to make a supporting adapter.
jfiresto:
Just a quick follow up about eyepieces for the M7A (or other Wild stereo microscopes). As I wrote earlier, you want them to be adjustable if they were not specifically for Wild or later Leica M-series microscopes. The intermediate image in an M7/M7A is a few millimeters deeper into the eyepiece tubes than the common 10mm.

Finding third party eyepieces that are parfocal can be a bit hit and miss. Not only should be they be adjustable, they should be adjustable over a fairly wide range. The last pair of inexpensive 10X/22 eyepieces I bought did not adjust far enough. Next year, I will try some that copy an old Zeiss design and are marked WF10X/23.

The Wild M7A has enough resolution to support 20X eyepieces without "empty magnification". This let you effectively double its maximum zoom, from 31X to 62X, by simply swapping 20X eyepieces for 10X – when you need a quick, closer look.

(Merry Christmas to all who celebrate it!)
zkrx:
Hey jfiresto,

Sorry for the 3-month delay, I rotate between many projects and some of them stay on the back burner for longer that I'd like... This and the fact that my optics knowledge is near zero, so most of the technical terms are like Chinese to me. But I have a long Xmas holidays ahead, so I should find some time to get myself up to speed. Anyways.

First of all, let me post this picture for my personal reference (or for any noob like me :D):



--- Quote ---The M3 monocular tube could be the oldest of all and was typically used to create a photo- and/or video-only microscope. What is its internal tube diameter? That will suggest what you will need for intermediate optics. The phototubes I am familiar with have either a 38mm I.D. or a trifle more than 30mm I.D.
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I measure an internal diameter of precisely 30mm on this tube.


--- Quote ---What model Nikon?
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I have a Nikon D7200.


--- Quote ---This let you effectively double its maximum zoom, from 31X to 62X, by simply swapping 20X eyepieces for 10X – when you need a quick, closer look.
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This probably sounds trivial, but this is actually good to know. I attached pictures of my eyepieces at the end of this post for people's reference.

My brother-in-law saved a 3D printer from the junkyard. It took me some time to repair but now it is perfectly functional. I'd like to print an adapter for my Nikon, but I need to dig into this deeper. Especially about the "flange focal distance" bit you mentioned. Anyway, here are semi-random links that I saved a few months ago, but I've yet to give them more thought:

- https://www.mikroskopie-forum.de/index.php?topic=33015.0 (Nikon - Wild adaptation with some links to thingiverse)
- https://www.thingiverse.com/thing:131769
- https://www.thingiverse.com/thing:237376
- https://www.thingiverse.com/thing:4369162
- https://www.microbehunter.com/microscopy-forum/viewtopic.php?t=7135 (talks about tube adaptation stuff)
- http://www.lenaturaliste.net/forum/viewtopic.php?f=155&t=22658 (interesting Wild derivation tube)

Merry Christmas to all of you :).
jfiresto:
This is funny. Normally, people get annoyed if you bump an old thread, but that has not happened yet.

If your 30mm photo tube is like the one I have, you can stick a standard eyepiece in the tube and share the view with another observer. Does the photo tube have a part number I might be able to look up?

The eyepiece takes the intermediate image that is perhaps 15mm inside the tube and reprojects it above the eyepiece to your eyeball. You will need a relay lens like that to re-project the image all the way to your DSLR's sensor. You could try a "high eyepoint" eyepiece and do this "afocally". You find a suitable lens for the DSLR, focus it on the image that is above the eyepiece and have the camera take the place of a human eyeball. I write "suitable" because my strong impression is that people who roll their own often discover a good combination through a fair bit of trial and error. Afocal projection is the same that people use when they take pictures by holding a mobile phone over an eye piece. That will give you an idea about the projected image and the lens you will need.

You can get adapters where someone has done all that work for you, but the good ones from, for example, promicron or lmscope, tend to be pricey. That convinced me to first try "direct projection". Instead of changing the microscope's image to match the camera, you choose a camera and a way to mount it to match the image out of the microscope. You can do this pretty quickly and cheaply with a 38mm photo tube, if you do not need live video. I spent a few hours and less than 90 euros for my first set up, including a 12 megapixel, µ4/3rds camera with a one year, camera store guarantee. I was going to try direct projection with a 30mm photo tube, by decapitating the tube, but found a 38mm one before I could do something rash.
zkrx:
I don't know, the thread's not that old and we're still on topic which is sharing m7a experience. Besides, information on that brand is quite rare.

There's no part number on that tube, someone wrote "Phototubus für M3" with a marker on it. You'll find attached all the pictures from the auction.

I found this document that mentions this tube on pages 2 and 4:
http://www.nyms.org/wp-content/uploads/2012/04/Newsletter-2015-10-NYMS-Extended-email.pdf

According to some more googling, part number would be "Photo Tube A 256528". I found this thread where someone wants to do the same:
https://www.photomacrography.net/forum/viewtopic.php?t=41838

And this Wild document with some diagrams, there's probably something of interest in there:
http://www.science-info.net/docs/wild/M5-10m.pdf

You can find a diagram with 256528 on page 19. There's a part 184947 which goes on top of the tube called "Camera clamping ring diam. 33mm":
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