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PostPosted: Tue Jun 12, 2018 6:42 pm 
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Joined: Fri Mar 30, 2018 4:12 pm
Posts: 97
Location: Germany, Karlsruhe
Maybe you find the below interesting:
In 1965 the manufacturer Leitz issued their "Orthoplan" microscope. Characteristic of this microscope was the very large field of view - as a result of the tube/eyepiece diameter of 30 mm diameter. Previously the Periplan eyepieces only had a diameter of 23.2 mm. The large GF/GW eyepieces achieved a FOV of "28"!

A comparison: A Zeiss Universal usually has a FOV of 14.5 (by use of FOV 18 eyepieces) or max. FOV 16 (by use of FOV 20 eyepieces). This is because the tube head of the universal always has a magnifician factor of 1.25
(I never really understand why Zeiss did design the Universal in that way. The Standard WL, 14 or 16 or whatever usually do not have a tubus factor.)

At that time Dr. Michel was head of development at Zeiss. Michel knew how to react by original ideas. When Leitz launched his large research microscope Orthoplan and put in advertising the importance of particularly extended visual fields in center - which, however, could only be achieved with larger diameter tubes.
Michel replied with his so-called "large field" noice piece (revolver). In this case, the scale number of the intermediate image was reduced by 0.8 with an intermediate optics, which increased the image field accordingly. The reduction was compensated by using stronger eyepieces, so instead of a KPL 10x use a KPL 12.5. This could be done because the lenses used so far for a field of view of 20 had a reserve for a field of view number of 25 for safety reasons*).

I have such a large field noice piece in use with my Zeiss Universal. I use the KPL 12.5/20 eyepieces, what results in FOV of 25. It is really a very impressive image & I like it very much. No way to step back to use the conventional noise piece!

Also like to mention that for the Standard WL/14/16/18/RA there was the Optovar magnificion changer. It usually had factor 1.0 up to 2.0. However very few of them had a also a magnification factor starting with 0.8, and they were also called "large field Optovar" (GroƟfeld Optovar). I used to own such, but somehow I sold it to balance for other investments. I would not sell this jewel today - never find it again.

Does anybody also uses this kind of large field stuff with their Universal or maybe Standards?

*) took this info from the book "Geschichte der Mikroskopie" (Autor Dieter Gerlach)

_________________
sincerely Jochen
My microscopes: Zeiss inverse IM35, Zeiss Standard (RA, WL, Universal, Junior), Stemi III
Youtube: https://www.youtube.com/channel/UCVio3U ... cg-Fm2su3w


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PostPosted: Tue Jun 12, 2018 7:15 pm 
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Joined: Mon Aug 21, 2017 9:02 pm
Posts: 831
My Standard GFL arrived with two Zeiss 10x18 eyepieces, of a high eyepoint.
However, they were undergoing delamination. Besides, their top end is a strangely oval, hard plastic shape. I wonder why has Zeiss made such an inconvenient eyepiece. They press against the eyes of the beholder or into his spectacles!

So instead of the originals, I am using a pair of Olympus 10x/20 L eyepieces. They provide a wider FOV, which is very pleasing
(relative to the smallness of the microscope at least). For the phototube I use the Zeiss 8X KPL eyepiece. I still lack a proper pair of flexible rubber eyepiece tops - the inexpensive Chinese covers available on eBay are a poor stuff.

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Zeiss Standard GFL+Canon EOS-M10


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PostPosted: Tue Jun 12, 2018 8:22 pm 
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Joined: Fri Mar 30, 2018 4:12 pm
Posts: 97
Location: Germany, Karlsruhe
Hobbyst46 wrote:
My Standard GFL arrived with two Zeiss 10x18 eyepieces, of a high eyepoint.
However, they were undergoing delamination. Besides, their top end is a strangely oval, hard plastic shape. I wonder why has Zeiss made such an inconvenient eyepiece. They press against the eyes of the beholder or into his spectacles!


Not sure what you mean with oval shape. So a kind of protectors on top of the eyepieces? You could remove?
Delamination is a common problem with those eyepieces. If it is starting just at the edge of the ocular you might just put a drop of immersion oil into and it will fill the gap. Otherwise Caedex balsam will do better to repair.

Hobbyst46 wrote:
So instead of the originals, I am using a pair of Olympus 10x/20 L eyepieces. They provide a wider FOV, which is very pleasing


I also checked these Olympus 10x/20L eyepieses. They are nice. But they cause a slight incorrect chromatic error at the outer diameter of the FOV so finally replaced by the KPL's.

Hobbyst46 wrote:
(relative to the smallness of the microscope at least). For the phototube I use the Zeiss 8X KPL eyepiece.

I also use such :-)

Hobbyst46 wrote:
I still lack a proper pair of flexible rubber eyepiece tops - the inexpensive Chinese covers available on eBay are a poor stuff.

What is the reason why you want to use those rubbery tops?

_________________
sincerely Jochen
My microscopes: Zeiss inverse IM35, Zeiss Standard (RA, WL, Universal, Junior), Stemi III
Youtube: https://www.youtube.com/channel/UCVio3U ... cg-Fm2su3w


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PostPosted: Tue Jun 12, 2018 9:30 pm 
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Joined: Wed May 16, 2018 2:40 am
Posts: 51
Location: California
ImperatorRex wrote:
What is the reason why you want to use those rubbery tops?


One reason I like rubber tops is because I wear glasses and the rubber prevents scratches on the lenses. The worst are the eyepieces on my Leitz microscope. Its eyepieces have no rubber and hard metal edges that can really scratch my glasses.


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PostPosted: Wed Jun 13, 2018 12:03 pm 
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Joined: Mon Aug 21, 2017 9:02 pm
Posts: 831
JGardner wrote:
ImperatorRex wrote:
What is the reason why you want to use those rubbery tops?


One reason I like rubber tops is because I wear glasses and the rubber prevents scratches on the lenses.
Same reason.

_________________
Zeiss Standard GFL+Canon EOS-M10


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