Field of View - Zeiss Universal vs. Leitz Orthoplan

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ImperatorRex
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Field of View - Zeiss Universal vs. Leitz Orthoplan

#1 Post by ImperatorRex » Tue Jun 12, 2018 6:42 pm

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" nose 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" (Großfeld 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)
Last edited by ImperatorRex on Mon Jun 29, 2020 4:05 pm, edited 1 time in total.

Hobbyst46
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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#2 Post by Hobbyst46 » Tue Jun 12, 2018 7:15 pm

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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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#3 Post by ImperatorRex » Tue Jun 12, 2018 8:22 pm

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?

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#4 Post by JGardner » Tue Jun 12, 2018 9:30 pm

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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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#5 Post by Hobbyst46 » Wed Jun 13, 2018 12:03 pm

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.
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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#6 Post by redflanker » Thu Jan 03, 2019 8:31 am

Perhaps Zeiss 'standards have survived to this day?This is my Zeiss Primo Star ,and the tube diameter of 10x20 eyepiece is still 30mm.
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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#7 Post by einman » Thu Jan 03, 2019 3:27 pm

I enjoy my Leitz 10x/26mm fov eyepieces. The view is amazing! I also use Nikon's 10x/26.5 on one of my stereoscopes..also amazing. Both use 30 mm tubes.

As mentioned that FOV could be increased by using 8x eyepieces but alas I do not have a set.

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#8 Post by desertrat » Thu Jan 03, 2019 10:12 pm

I wonder what kind of field of view is given by the old A/O cat. 146 eyepieces I use? The tube diameter is the old style 23.2 mm, so I guess the field would not be as wide as the modern eyepieces. Still, they seem wide enough for me. It's probably just as well that I've never seen the extra wide fields that the modern eyepieces give.
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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#9 Post by MicroBob » Sun Mar 10, 2019 6:52 am

A way to improvise rubber eye cups is to pull a piece of bicycle inner tubing over them. Then turn the bicycle inner tube over itself and back over the eyepiece. This way you get a broader rounded edge towards the eyes.

Bob

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#10 Post by Hobbyst46 » Sun Mar 10, 2019 9:15 am

MicroBob wrote:A way to improvise rubber eye cups is to pull a piece of bicycle inner tubing over them. Then turn the bicycle inner tube over itself and back over the eyepiece. This way you get a broader rounded edge towards the eyes.

Bob
Hi Bob, excellent idea! most bike tires are tubeless but the inner tubing is still available from bike shops.
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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#11 Post by ImperatorRex » Sun Jul 28, 2019 4:59 pm

I created a comparision for the Zeiss Universal / Phomi:
Normal field of view versus the FOV with large field objective turret. It really makes a big difference.

Image

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#12 Post by Bradscopegems » Tue Nov 03, 2020 1:52 am

Am I alone in finding that there is a downside to wide-field eyepieces? The reason is that the observer's head must be held more steady than with low FOV eyepieces such as the classic Zeiss 8x eyepieces with FOV 18 or 20mm. The distance of the eye from the top of the eyepiece must be kept almost constant, or vignetting of the image by the observer's pupil is likely, since the envelope of beams increases more rapidly in diameter above and below the diameter of the Ramsden disk. I find that this produces strain in the neck and shoulders during prolonged observation. In ordinary vision, such as reading a book or looking at distant objects, there is no requirement for submillimeter accuracy in maintaining the eye-to-object distance, so the wide-field eyepiece is quite unnatural.

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#13 Post by PeteM » Tue Nov 03, 2020 3:46 am

I've found the same issue with an older Leitz super widefield head. Eye position is very unforgiving.

However, a newer Leica (DMLB and DMRB) and a Nikon (Eclipse ME600) with a 25mm plus fields of view offer highly immersive and comfortable views. So, I'd say much depends on the design of the eyepieces.

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#14 Post by MicroBob » Tue Nov 03, 2020 6:56 am

Hi together,
interestingly the top manufacturers have later reduced the maximum field of view a bit from 28mm on the Orthoplan (were there bigger fields at Zeiss Jena Microval series?) down to 25-26mm. So apparently 28mm might have been a bit over the top considering all affected design tasks. On my compoung microscopes I have a maximum field of view of 18mm on 10x eyepieces. This gives a certain angle of field of view. When used on the Phomi 1 with it's optovars minimum 1,25 tube factor this view angle stays the same but the view is enlarged more and thus shows less field of view. In practical microscopy I don't find myself looking at the borders of the image often. So these extreme wide viewing angles might be more useful for scanning through slides when looking for something than for detailed observation. The sharp center of the human vision is quite small anyway. And yes, viewing angles and eyepiece designs will for sure be rated very differently by differnt people!

Bob

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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#15 Post by mrsonchus » Tue Nov 03, 2020 11:38 am

I had no such trouble with my Orthoplan's 'ultra-wide' FOV. I did notice the difference immediately when I stepped up to the larger field from the 'scope it replaced though. I found that I was able to 'look around' the FOV as it were, moving my eyes right and left etc almost as if looking through a window!. I seemed naturally never to attempt to focus on the entire FOV at once, but as said, to 'look around' intuitively...
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Re: Field of View - Zeiss Universal vs. Leitz Orthoplan

#16 Post by ImperatorRex » Tue Nov 03, 2020 7:25 pm

For me I instantly enjoyed working with the KPL 12,5x Objektives (that have a FOV of 18) together with the wide field nose piece. This makes a FOV of 22.5, what I still can observe without moving the eyes. So its relaxing and I like this - it is really big cinerma.
I switched to KPL 12,5x Objektives (that have a FOV of 20), what makes the FOV of 25. It was a bit stressing since I tend to move my eyes to observe the outer range of the FOV, what is not really relaxing. But after some days I got used to it and I simply do not try to observe and spot the outer borders of the FOV. Still good to have a large FOV, but I think for me the optimum is a FOV of 22.5.
I would not like to step back to the "normal" FOV of 14.5 that the Phomi or Universal offers with the 1.25 tube factor.

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