3.2x Objective wont focus

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MicroBob
Posts: 1280
Joined: Sun Dec 25, 2016 9:11 am

Re: 3.2x Objective wont focus

#31 Post by MicroBob » Mon Aug 05, 2019 5:33 am

May be you can find your objective in one of the brochures that can be found here: http://www.leitz-ortholux.de/links.php
In some tables the free working distance is stated.

Bob

MichaelG.
Posts: 1393
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: 3.2x Objective wont focus

#32 Post by MichaelG. » Mon Aug 05, 2019 5:39 am

Thanks for the photos and numbers
We can't really justify treating that as a 'thin lens' ... So, without some idea of the optical design, calculation becomes guessing ... but your practical result is not unexpected.

MichaelG.
.
Edit: It may just be coincidence, but it looks like someone has been experimenting with this example:
https://www.ebay.com/itm/Leica-Leitz-3- ... 3015897278
Too many 'projects'

MichaelG.
Posts: 1393
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: 3.2x Objective wont focus

#33 Post by MichaelG. » Mon Aug 05, 2019 6:09 am

I have just downloaded this useful looking document:
http://microscope.database.free.fr/500_ ... rriers.pdf

Maybe we can find enlightenment there.

MichaelG.
.

Eureka:
Leitz_3.2x.png
Leitz_3.2x.png (172.63 KiB) Viewed 1262 times
Too many 'projects'

MichaelG.
Posts: 1393
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: 3.2x Objective wont focus

#34 Post by MichaelG. » Mon Aug 05, 2019 8:12 am

As a footnote to this discussion:

This patent gives a good idea of what is involved in designing parfocal low power objectives
https://patents.google.com/patent/US4027951A/en
https://patentimages.storage.googleapis ... 027951.pdf

MichaelG.
Too many 'projects'

jb89
Posts: 47
Joined: Fri Jun 21, 2019 9:09 am
Location: Denver, Co

Re: 3.2x Objective wont focus

#35 Post by jb89 » Mon Aug 05, 2019 1:06 pm

MichaelG.,

Looks like it's a mystery solved!

I guess I just need to consult you guys before I start buying things. (at least I didn't pay too much for this I guess)

With so many different types of objectives it's easy for a beginner to make mistakes or get something that isn't exactly what they thought they were getting.

Thanks again for all of the info and effort you guys have put in to figuring this out, looks like I have a lot to learn(already knew that though!)

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