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Leitz ortholux to SM adaptatation

Posted: Fri Nov 30, 2018 1:30 pm
by Aslan
Hello everyone.

I was thinking of modifying an Ortholux trinocular head for use on an SM microscope. Before I commit to surgery I was wondering if anyone else has had any experience doing such a thing. Essentially I want to remove the small piece at the bottom of the trinocular head and replace it with the base of the binocular head that came with the SM microscope.

Any thoughts?

Re: Leitz ortholux to SM adaptatation

Posted: Fri Nov 30, 2018 3:36 pm
by 75RR
Could you post some images of the small piece at the bottom and the base of the binocular head that came with the SM microscope
What is the reason for this conversion and is it reversible?

Re: Leitz ortholux to SM adaptatation

Posted: Sat Dec 01, 2018 4:53 am
by PeteM
A photo would help me as well. I'm guessing you want to go to a smaller dovetail (actually not quite dovetail for Leitz) connector the your SM stand?

In some cases, I've been able to adapt heads by either turning down a dovetail or making a semi-circular (180 degrees) shim with angled sides to match a larger dovetail. The latter is sort of like making a funnel-shaped washer and then cutting it in half -- everything fits snug around the small dovetail and replicates the larger dovetail.

With Olympus, you can simply unscrew the dovetail, which makes things easy. With Reichert of the MicroStar IV era you can unscrew the square base and chuck it in a 4 jaw chuck. With infinity systems it's just easier to make up an intermediate piece and add a polarizer while you're at it.

Main thing to watch out for, besides getting the dovetail properly sized, is that the tube lens and path length are appropriate for your modification.

The only Leitz head mod I've tried so far was adapting an ultra wide Leitz trinocular to an Olympus scope -- here the dovetail simply unscrewed and it was fairly easy to make up a new one of whatever size needed. However, even with Olympus eyepieces tried at different heights and 26FN Olympus objectives, it wasn't nearly as spectacular as I'd hoped -- probably a mismatch of tube lenses. Leitz to Leitz you might be OK as long as you're not mixing 160mm and 170mm tube length heads.

Re: Leitz ortholux to SM adaptatation

Posted: Sat Dec 01, 2018 9:03 am
by MicroBob
I have no precise information on the tubes but I think Leitz had several similar looking tubes with different properties in this era. For best performance it would be good to keep the tube length right. You might set up the microscope and a slide to sharp focus then put the new head without dovetail on in and see how it fits.

Leitz 170mm tube was accompanied with eypieces that pick up the image 18mm down the tube. With 160 it was 10mm. This is 152 to 150mm so not much difference. On 160mm tube 160mm objectives and 170mm objectives can be mixed without problems when used with 10mm eyepieces. Leitz 160mm eyepieces are named for instance 10x18.

Bob

Re: Leitz ortholux to SM adaptatation

Posted: Sat Dec 01, 2018 4:23 pm
by desertrat
I have mounted some old 37mm parfocal Leitz objectives, made in the 1930s, on my AO 4 Series stand and used the standard AO cat. 146 widefield eyepieces. Except for the fact that the objectives were less parfocal than when mounted on their original monocular Leitz stand, image quality had not deteriorated, as far as I could tell.

The difference between 170mm objectives and a 160mm tube length stand didn't seem to cause any serious problems except for some error in parfocality between the objectives.

Re: Leitz ortholux to SM adaptatation

Posted: Sat Dec 01, 2018 5:46 pm
by MicroBob
Older monocular stands sometimes had tubes with adjustable length, even with scales on it. This was used to compensate for varying cover glass thicknesses. The impact on image quality is highest with the stronger objectives. I don't know when this really get a practical meaning - maybe 5 to 7mm difference still ok?

Re: Leitz ortholux to SM adaptatation

Posted: Sat Dec 01, 2018 6:24 pm
by desertrat
Steve Neeley has a list of objective to eyepiece specs for various makers at this page:

http://user.xmission.com/~psneeley/Pers ... pieces.htm

For the old Leitz objectives, the distance from objective flange to first image in eyepiece was 152mm

For the old 160mm AO/Spencer objectives it was 148.7mm

So the actual difference was only a little over 3mm.

However the old 10X Periplan eyepiece that came with the Leitz microscope may have had different corrections than the Cat. 146 eyepieces used with the 4 series. Also, there is the matter of the 4 series having a tube lens just above the objectives. Still, I couldn't see any obvious differences in the performance of the objectives between the two stands, except the AO eyepieces have a much wider field, and the old Leitz objectives may not have been designed to cover a wider field.

Re: Leitz ortholux to SM adaptatation

Posted: Wed Dec 05, 2018 5:58 pm
by Aslan
Thank you to all for your replies. I did some exploratory dissection on the head only to discover that the prisms are attached to the base I want to replace. It might still be possible but it is beyond my capabilities. I am going to end up putting up the trinocular up for sale on ebay.