C-mount OMAX camera on binocular Zeiss standard EPI microscope

[erikwetterskog]

Dear forum,

I'm posting for the first time here (and certainly a beginner). Long story short, I work at a Science Education Center in Sweden. We have a ton of conventional compound microscopes that we use in our activities, but until recently lacked a microscope with EPI illumination. In this particular case, we wanted a metallurgical microscope to show some microfabricated devices in a school program with a "build your own computer"-theme for 10-13 year olds.

I managed last week to get a hold of a busted up Zeiss inverted standard metallurgical microscope from the University with a standard set of (160) EPI-plan objectives (4, 8, 16, 40, 80x) and KPL8x eyepieces on a binocular head. The scope lacked a lamp, so I have purchased a kit from Retrodiode, but currently I'm testing with a different LED-kit for another microscope (that is why it looks so wonky), still waiting for the LED-kit.



Beforehand, I already purchased an OMAX 8 MP C-mount camera with a standard 23.2 mm 0.5x reduction lens. I was happy enough when I realised that I could slide the reduction lens directly into one of the eyepieces. Unsurprisingly, I get a boatload of chromatic aberration (see picture below). After some forum searching I realized that the eyepieces provide correction for this. Also, the field is not flat as the edges of the image is blurry. I am assuming this is also due to the lack of correction in the reduction lens.



This leads me to two questions.

1. What I wonder now is if there is a way to mount the OMAX camera afocally onto the KPL8x with some sort of cheap adapter, either with or without the reduction lens to get rid of the CA and get a flat FOW. We are also going to look at CD-rom discs, and I fear that the CA will make the written data look really wonky. I have read that people use various method to mount DSLRs, but it will not work here. In this case, we would much prefer to use a an OMAX type C-mount camera, as we need the system to be relatively portable, cheap and simple for a non-expert to handle. The TOUPLite software is perfect for classroom demonstrations etc.

In the long run, I guess we can survive with the CA, but i would love to get it "right".

2. Secondly, I wonder if the EPIplan HD-objektives will fit with this microscope. They can be bought cheap and have a slightly longer WD which certainly would help. Would they be and improvement?

Looking forward to your input!

[MichaelG.]

Welcome, Erik ... and good luck with your teaching project.

Regarding the photo eyepiece issue:
Have a look at how Motic does it [by adding a lens to the camera]
https://youtu.be/xqSWITLUeLM

Happy to discuss this further, if it isn't obvious what's required.

MichaelG.
.

Edit: Your camera uses "Image sensor: Aptina 1/2.5" color CMOS"
which suggests that, following Motic's approach, a 12mm lens would be suitable.
see the tabulation: https://www.motic.com/As_Moticam_CMOS/product_210.html
Like most 'macro' lenses; the Motic lenses are of simple construction [sorry I don't know the detail] but work very well.

[erikwetterskog]

Welcome, Erik ... and good luck with your teaching project.

Regarding the photo eyepiece issue:
Have a look at how Motic does it [by adding a lens to the camera]
https://youtu.be/xqSWITLUeLM

Happy to discuss this further, if it isn't obvious what's required.

MichaelG.

Thanks for the input. I looks like the right thing. Looking around, I find various Moticam adapters. For instance I go onto Fischerscientific's Swedish site and see two options, at really different prices (30 USD vs 1700 USD). The outer diameter of my eyepieces are 25mm tube, and 27.9 mm (non-removable ring at the end) respectively.

https://www.fishersci.se/shop/products/ ... /p-8546009

If its going to happen, I need to do it on the "cheap", is there a less expensive Ebay adapter? Does the adapter need to have a lens?

[MichaelG.]

Erik

Hopefully you have seen my edit

All you really need is a 12mm lens and whatever you can 'cobble together' for the mechanical side.
Learn from Motic ... but build your own !!

MichaelG.

[Hobbyst46]

Welcome Erik,
My upright Zeiss microscope has some features in common with your setup. Like the illumination (cool white LED). And (I believe) a fairly similar eyepiece camera with 0.5X reduction lens. I use it "as is", without a Zeiss corrective eyepiece. In contrast to the Canon camera which is interfaced afocally, on top of the 8X KPL eyepiece in the photo tube of the trinocular head.
So the subject is of interest to me too.
This previous post does not answer your questions but might be informative:
viewtopic.php?f=9&t=7145&p=63339&hilit=GFL#p63339

[MicroBob]

Hi Erik,
the epiplan objectives are 160mm tube length. HD means epi darkfield and they have M24 thread. For electronics epi brightfield is much improved with polarizers.
For research grade compound microscopes like the Zeiss Standard WL or Phomi or Universal Epi condensers were available. Sometimes these were bought even from biological departments.

Bob

[erikwetterskog]

Wow,

What a great deal of input, I guess I have to build my own adapter. Personally, I am not very skilled, but I have a couple of colleagues who could probably help out.

Regarding your input,

All you really need is a 12mm lens and whatever you can 'cobble together' for the mechanical side.
Learn from Motic ... but build your own !!

I'm wondering if you have any suggestions on where to start out looking. If I simply google 12 mm lens, I end up with a ton of camera lenses. On Ebay it is a bit better, would something like this do the trick?

https://www.ebay.co.uk/itm/12mm-720P-F2 ... ctupt=true

Hi Erik,
the epiplan objectives are 160mm tube length. HD means epi darkfield and they have M24 thread. For electronics epi brightfield is much improved with polarizers.
For research grade compound microscopes like the Zeiss Standard WL or Phomi or Universal Epi condensers were available. Sometimes these were bought even from biological departments.

Bob

Hmmm, I was over at the University and one of the scopes I was choosing from was a grey Zeiss that had a slot with a polarizer/analyzer in the binocular head. I ended up not taking it, since the XY-table was defect (did not move). Should I go back and switch it out (assuming that it has a polarizer in the condenser)? Will the extra contrast from polarization microscopy be worth it?

What I'm wondering is, is the light sufficient to run a live image in the classroom with crossed polarizers (assuming that is what we need to use), or is it really long exposure times needed (i.e. no live image worth showing)?

We In the classroom, we are basically going to quickly explore couple of microchips for 10 minutes or so, and we need the live image to keep the young ones attention.

Thanks again!

[MichaelG.]

All you really need is a 12mm lens and whatever you can 'cobble together' for the mechanical side.
Learn from Motic ... but build your own !!

I'm wondering if you have any suggestions on where to start out looking. If I simply google 12 mm lens, I end up with a ton of camera lenses. On Ebay it is a bit better, would something like this do the trick?

https://www.ebay.co.uk/itm/12mm-720P-F2 ... ctupt=true

Erik,
That lens is only in a 12mm mount, and is rated '720p' so I doubt it would have the covering power, or the resolution, to do justice to your camera.
What I have found, however, is that Ted Pella lists the Motic lenses [in their focusssing c-mounts] at better prices than I expected. ...
See just below half way down this page:
https://www.tedpella.com/cameras_html/camera1.htm
... So you may want to ask about shipping, or to search for someone local to 'price match'

The mechanical attachment to the microscope is simple enough to DiY, so it's probably not worth spending money on the Motic components for that.

You might also look at SurplusShed ... Fred has a great stock of suplus lenses at good prices, and is very fair with his shipping to Europe.
https://www.surplusshed.com/search_lenses.php


MichaelG.

P.S. ... I am still trying to determine what optical formulation Motic uses; and will of course share that information if I find it.

Edit: This lens should better suit your camera [sensor size and resolution], and is for CS mount
https://www.ebay.co.uk/itm/12mm-CS-Moun ... 2722225576
... but I have no idea what quality it might be.

Note that C and CS mounts are the same size, but there is approximately 5mm difference in the designed flange-to-sensor distance [this may not matter for what you are doing]
http://www.k3pgp.org/ccsmount.htm

[Hobbyst46]

...Hmmm, I was over at the University and one of the scopes I was choosing from was a grey Zeiss that had a slot with a polarizer/analyzer in the binocular head. I ended up not taking it, since the XY-table was defect (did not move). Should I go back and switch it out (assuming that it has a polarizer in the condenser)? Will the extra contrast from polarization microscopy be worth it?...
What I'm wondering is, is the light sufficient to run a live image in the classroom with crossed polarizers (assuming that is what we need to use), or is it really long exposure times needed (i.e. no live image worth showing)?
We In the classroom, we are basically going to quickly explore couple of microchips for 10 minutes or so, and we need the live image to keep the young ones attention.

I suspect that what you saw at the University may have been an upright "biological" microscope. With trans-illumination, that is, light from the lamp, through the condenser, passes through the specimen. To look at microchips, you need epi-illumination. That means, the light beam shines onto the specimen and what you see is reflected light. This is so regardless of the microscope - inverted or not. If the grey Zeiss you saw has no epi-illumination, it is not suitable for the inspection of microchips, and the polarizer/analyzer do not help in this respect. There are also specific microscopes configured for epi-illumination, like for example metalurgical microscopes. Typically the objectives on them are thicker than the ordinary common objectives from the same era. But this is not an absolute requirement.

[erikwetterskog]

I suspect that what you saw at the University may have been an upright "biological" microscope. With trans-illumination, that is, light from the lamp, through the condenser, passes through the specimen. To look at microchips, you need epi-illumination.

To clarify, the grey microscope mentioned above (with the filter slot) certainly was a EPI/metallurgical scope. There were a couple of different models, but all of them were inverted metallurgical microscopes (like the one in my picture). I picked out the one with the best focus motion, but I was sort of in a rush. It looked a bit newer (still had 160 mm objectives), and a broken conventional XY table.

[75RR]

It might be an idea to take some photos (with your phone) of the microscopes available in that department.

If you post them here we can see if there is a better one for your needs. Note: to upload directly max size is 1024 x 1024

[MicroBob]

Hi Erik,
For epi illumination different techniques are used depending on the object you have on the table. Dark field is done with the fat objectives with a ring mirror around the objective. Zeiss West name for this is HD. The reflector in the epi condenser has to fit to the objective: Reflector D for dark field, H-Pl for bright field or pol.
For pol you need one pol filter in the lighting and one between objective and eye. A good place for a piece of pol foil is under the bino tube.

Reflected light is always much dimmer than transmitted light and pol makes it even darker. A 10W LED would be a good power source. Epi lighting was often used with mercury lamps that emit hard UV too. So be careful when playing around with microscopes with funny looking lamps.

Bob

[erikwetterskog]

Thanks again for good advice ya'll. This place is amazing! I have a bigger project with a Nikon L-Ke (my home microscope), and I am already looking forward to get input on that.

That lens is only in a 12mm mount, and is rated '720p' so I doubt it would have the covering power, or the resolution, to do justice to your camera.
What I have found, however, is that Ted Pella lists the Motic lenses [in their focusssing c-mounts] at better prices than I expected. ...
See just below half way down this page:
https://www.tedpella.com/cameras_html/camera1.htm
... So you may want to ask about shipping, or to search for someone local to 'price match'

Those prices seem pretty reasonable! I have bought a lot from TedPella in the past, when I was working in research. They have a Swedish agent who orders for you. I may just go for that actually.

Hi Erik,
For epi illumination different techniques are used depending on the object you have on the table. Dark field is done with the fat objectives with a ring mirror around the objective. Zeiss West name for this is HD. The reflector in the epi condenser has to fit to the objective: Reflector D for dark field, H-Pl for bright field or pol.
For pol you need one pol filter in the lighting and one between objective and eye. A good place for a piece of pol foil is under the bino tube.
Bob

I wonder if it would be possible to have a makeshift polarizing microscope with the scope I have? I'm thinking just by putting a pol-filter in the filter slot of the binocular and another one simply on top of the illuminator. I always assumed you needed a special condenser, not sure what my condenser is, I'll try to check that tomorrow at work. As I recall, there was only a serial number. And the only thing it "has" was a diaphragm.

EDIT: The LED kit I bought is a 10W unit.

I may go back to the university department after easter and peak again at the polarizing microscope. I'm guessing if it has a polarizer slot in the bino-head, it probably has the correct condensor. Not sure how easy it would be to repair a broken XY-stage tough.

[MichaelG.]

I wonder if it would be possible to have a makeshift polarizing microscope with the scope I have? I'm thinking just by putting a pol-filter in the filter slot of the binocular and another one simply on top of the illuminator.

Yes ... That works
All the fancy stuff is really about convenience, accuracy, and repeatability.

I saw one of these for the first time, recently: "NBS Polarspex"
http://www.brunelmicroscopessecure.co.u ... lides.html
... It's a very simple device, but provides the basics in a convenient package.
If you don't want the sample slides ... a DiY version should be easy, and cheap, to make !!

MichaelG.

[MicroBob]

A proper polarizing microscope is a precision measuring instrument with added imaging. In your case the pol filters are only used to increase contrast. Basic linear pol foil works very well for this.
You could use foil from some 3d cinema glasses, but they have to be arranged in a special order.

[erikwetterskog]

Hello again,

I just wanted to send you an update on the progress. I was out of work for a while, and did not manage to finish this project until now. In the end, I decided to purchase the Motic afocal adaptor from Ted Pella to try and improve the problems with CA.

But the result with the Motic adapter combo was extremely disappointing, with the chromatic abberation being as bad or worse as with the OMax reduction lens. Even worse, the illumination from the eyepiece tube using the afocal adapter does not cover the entire CCD uniformly (I have the Kpl 8x tubes), resulting in a very uneven illumination field. The image viewed directly in the eyepiece looks great however. As of now, I prefer the results with the OMax lens, I will try and post a comparison later.

Hopefully, I can find some other use for the adapter later. Overall, I'm a bit disappointed in the performance of this microscope, I previously used a trinocular Leitz Ortholux (?) stand of similar vintage, and with a simple LED source and the results were much, much better. I'll be back later with the final verdict.

[Scarodactyl]

That is quite odd. It is possible for the relay lens to introduce its own chromatic abberations, but even a fairly poor lens shouldn't do anything like what is seen in the earlier photo. Could you post a picture of the setup as it is now?

[MichaelG.]

That is quite odd. It is possible for the relay lens to introduce its own chromatic abberations, but even a fairly poor lens shouldn't do anything like what is seen in the earlier photo. Could you post a picture of the setup as it is now?

+1 for the surprise, and the request

[somewhat bewildered] MichaelG.