Trinocular Microscope Tube

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ojd01
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Trinocular Microscope Tube

Post by ojd01 »

Hello Everyone!

I have a Radical Trinocular Compound Microscope - which I purchased second hand. I thought the eyepiece viewer and trinocular head would be parfocal, however, the images on the live screen on the camera look nowhere near in line with the eyepieces.

The next thought would be that as the eyepieces are finite to 160, part of the trinocular head is not there, or it's totally out of line. Can the head tubes be purchased from anywhere? Or is there somewhere in the UK that can check the microscope out?

I already have the EOS-C mount adapter and everything fits just do not line up well to the eyepieces. It might be me being silly!

Any help would be amazing! :D

Owen
Instagram: @ojd_photo

Pau
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Re: Trinocular Microscope Tube

Post by Pau »

Please post detailed images of the microscope and photo attachment, then giving advice will be much easier
Pau

Alan Wood
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Re: Trinocular Microscope Tube

Post by Alan Wood »

Owen

Please can you post a photograph of the trinocular head and the camera adapter(s)?

And tell us which camera you are using?

C-mount cameras have only a short distance from the front of the camera to the sensor. Canon EOS digital SLRs have a much longer distance, so an EOS digital SLR will not normally be able to focus when attached to a C-mount adapter.

EOS M mirrorless cameras can work with C-mount adapters, but the corners of the image may be dark.

Under normal (non-COVID) circumstances, I would suggest taking your microscope to a meeting of the Leeds Microscopical Society where I am sure someone could diagnose the problem for you:
https://leedsmicro.rogershore.net/

Alan Wood

ojd01
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Re: Trinocular Microscope Tube

Post by ojd01 »

Hello Alan and Pau! Yes, this is very true - sorry I should have thought of that. Images are attached here.

The camera is Canon EOS 500D (I am hoping to change this once I am able to)

The adapter is C-EOS and that is held using a screw-on tube (tube is c mount size thread). That tube slots into the trinocular head.

I have a feeling the setup on the trinocular head is wrong and I am able to buy the parts needed to fix it, if I know what I am looking for.

https://www.photomacrography.net/forum/ ... ew&id=2806
https://www.photomacrography.net/forum/ ... ew&id=2807
https://www.photomacrography.net/forum/ ... ew&id=2808
Attachments
20210208_112759-min-min_x1000.jpg
20210208_112727-min-min_x1000.jpg
20210206_184742-min-min_750x1000.jpg
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ojd01
Posts: 49
Joined: Sun Nov 15, 2020 10:56 am
Location: Teesside, Middlesbrough, UK

Re: Trinocular Microscope Tube

Post by ojd01 »

Alan Wood wrote:
Mon Feb 08, 2021 4:27 am
Owen

Please can you post a photograph of the trinocular head and the camera adapter(s)?

And tell us which camera you are using?
Hi Alan! I have just posted the details and images above ^^^

Kind Regards

Owen
Instagram: @ojd_photo

Alan Wood
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Re: Trinocular Microscope Tube

Post by Alan Wood »

Owen

That is an unusual adapter.

Let's start with the vertical tube on the trinocular head.

1) Is the outside diameter 25mm?

2) Can you put one of the viewing eyepieces in it? If you can, is the image parfocal with the other eyepiece?

Alan Wood

ojd01
Posts: 49
Joined: Sun Nov 15, 2020 10:56 am
Location: Teesside, Middlesbrough, UK

Re: Trinocular Microscope Tube

Post by ojd01 »

Alan Wood wrote:
Mon Feb 08, 2021 5:23 am
Owen

That is an unusual adapter.

Let's start with the vertical tube on the trinocular head.

1) Is the outside diameter 25mm?

2) Can you put one of the viewing eyepieces in it? If you can, is the image parfocal with the other eyepiece?

Alan Wood
Hey Alan,

Images are attached too. I have somehow reversed the C mount screw-on part and screwed it into the larger part of the trinocular tube (1st image - camera has been taken away with the c mount adapter).

https://www.photomacrography.net/forum/ ... ew&id=2809

The lumen now open on the trinocular head tube is just about 25mm and will fit an eyepiece in (2nd image)

https://www.photomacrography.net/forum/ ... ew&id=2809

After tweaking the dioptres on the binocular eyepiece... the images now match in the binocular eyepiece and the trinocular head eyepiece. I am hoping that is right!

Owen :D
Attachments
20210208_124946_x1000-min_x1000.jpg
20210208_124933_x1000-min_x1000.jpg
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Pau
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Re: Trinocular Microscope Tube

Post by Pau »

First one question: does the adapter have any kind of lens or is it an empty tube?

In both cases you first need to make the microscope itself parfocalized:
1- set the comfortable distance between eyepieces
2a- set the diopter eyepiece tubes rings to 0 or to your eyesight graduation -or-
2b- If the binocular head shows graduation in the space between the eyepiece tubes put this graduation at the diopter eyepiece tubes rings
3- focus with the 10x and then with the 40X to a good glass covered microscope slide
4- If when you switch down to 10X and 4X objectives you just need a bit of refocusing with the fine focus knob it's OK, but also test it upwards
5- If focus is not maintained when changing objectives, repeat #3 and then refocus only with the eyepiece rings and repeat the procedure until all is approximately parfocal. Can seem complex but it's just a bit of practice needed
Pau

Alan Wood
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Re: Trinocular Microscope Tube

Post by Alan Wood »

Owen

We are making good progress.

What you need now is one the adapters that were common for 35mm SLRs. They are usually in 2 parts. The lower part clamps to a 25mm tube and an eyepiece fits inside it. The upper part provides a few inches of extension and has a T-mount on top. You will need a T-mount adapter for Canon EOS, easy to find new on eBay.

Brunel Microscopes have a suitable used SLR photography adapter at a reasonable price, one up from the bottom of this page:

http://www.brunelmicroscopessecure.co.u ... ories.html

That should get you close to parfocality between camera and viewing eyepieces. You can tweak by lifting the eyepiece a bit (a rubber band will hold it) or lifting the adapter a bit.

Alan Wood

ojd01
Posts: 49
Joined: Sun Nov 15, 2020 10:56 am
Location: Teesside, Middlesbrough, UK

Re: Trinocular Microscope Tube

Post by ojd01 »

Alan Wood wrote:
Mon Feb 08, 2021 6:21 am
Owen

We are making good progress.

What you need now is one the adapters that were common for 35mm SLRs. They are usually in 2 parts. The lower part clamps to a 25mm tube and an eyepiece fits inside it. The upper part provides a few inches of extension and has a T-mount on top. You will need a T-mount adapter for Canon EOS, easy to find new on eBay.

Brunel Microscopes have a suitable used SLR photography adapter at a reasonable price, one up from the bottom of this page:

http://www.brunelmicroscopessecure.co.u ... ories.html

That should get you close to parfocality between camera and viewing eyepieces. You can tweak by lifting the eyepiece a bit (a rubber band will hold it) or lifting the adapter a bit.

Alan Wood
Hey Alan,

This is amazing thank you!

I will purchase the adapter now from Brunel! I believe I have a EOS T-adapter so that's lucky.

I will get back on this thread once it is all together!

Kind Regards

Owen
Instagram: @ojd_photo

Pau
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Re: Trinocular Microscope Tube

Post by Pau »

Owen, we were writing at the same time :D

I think that your best option is the afocal method, take a look at https://www.photomacrography.net/forum/ ... =8&t=15607

If your objectives don't need compensation at the eyepieces and you have enough clearance* you can also set up a short empty adapter that put the sensor at the same height where the eyepiece expects the objective primary image: 10mm under the end of the tube shown in your last image once the microscope itself is parfocalized (see my former post)

* the Canon EOS flange focal distance is 44mm (from the camera bayonet to the sensor). If the upper removable tube shown is 54mm or longer this can be done.
Pau

Pau
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Re: Trinocular Microscope Tube

Post by Pau »

The method with the adapter proposed by Alan is a classic one called "eyepiece projection"

It will work well enough although with it you force the eyepiece to act as projective raising it over its design position
It could be problematic with high NA objectives and you could have lesser parfocality if not perfectly tuned
Pau

ojd01
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Re: Trinocular Microscope Tube

Post by ojd01 »

Pau wrote:
Mon Feb 08, 2021 6:30 am
Owen, we were writing at the same time :D

I think that your best option is the afocal method, take a look at https://www.photomacrography.net/forum/ ... =8&t=15607

If your objectives don't need compensation at the eyepieces and you have enough clearance* you can also set up a short empty adapter that put the sensor at the same height where the eyepiece expects the objective primary image: 10mm under the end of the tube shown in your last image once the microscope itself is parfocalized (see my former post)

* the Canon EOS flange focal distance is 44mm (from the camera bayonet to the sensor). If the upper removable tube shown is 54mm or longer this can be done.
Hello! I am very sorry I missed your messages too. I am still getting used to the forum as I have not used that much.

I am looking at the attached forum thread now - thank you!

As I learn more, I will be able to take this information onto new microscopes in the future! :)

Kind Regards

Owen
Instagram: @ojd_photo

Alan Wood
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Joined: Wed Dec 29, 2010 3:09 pm
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Re: Trinocular Microscope Tube

Post by Alan Wood »

Owen

You mentioned changing your Canon EOS 500D.

That is a good camera for photomicrography. It works very well with the free EOS Utility software, which lets you control everything from your computer screen.

Alan Wood

ojd01
Posts: 49
Joined: Sun Nov 15, 2020 10:56 am
Location: Teesside, Middlesbrough, UK

Re: Trinocular Microscope Tube

Post by ojd01 »

Alan Wood wrote:
Tue Feb 09, 2021 4:09 am
Owen

You mentioned changing your Canon EOS 500D.

That is a good camera for photomicrography. It works very well with the free EOS Utility software, which lets you control everything from your computer screen.

Alan Wood
Hey Alan!

Thank you for the advice! I will definitely be sticking with it now and I will look at the EOS utility software! :D

EOS T-adapter has arrived! I am waiting on the Brunel adapter part which I should arrive in the next couple of days.

Kind Regards

Owen
Instagram: @ojd_photo

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