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The Leitz Vario-Orthomat Variable Zoom Photoeyepiece
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Cactusdave



Joined: 09 Jun 2009
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Location: Bromley, Kent, UK

PostPosted: Fri Oct 30, 2009 11:52 am    Post subject: The Leitz Vario-Orthomat Variable Zoom Photoeyepiece Reply with quote

Stimulated by the interest of fellow forumite and Vario-Orthomat user Hindpool, I thought I would post a few comments on this interesting and not well known zoom photoeyepiece. I’m not sure if this is the correct place to post this, but I’m sure our excellent moderators will move it if it isn’t.
The Leitz Vario-Orthomat was a film based automatic camera system which included a camera head which attached to a microscope photoport plus a separate electronic controller which automated the exposure process. These cameras either with or without the controller appear from time to time on Ebay and Lab surplus websites. At the heart of the system is a rather interesting zoom photoeyepiece which is readily separated from the body of the camera and which can then be adapted to work with modern digital cameras.
The lower part of the eyepiece is designed to fit into a standard Leitz 38mm photoport. At the top it offers a rather unusual M45 screw thread where it originally screwed into the shutter/ exposure control part of the camera. The diameter of the upper optic of the eyepiece is 20mm, compared with 14mm on a standard Periplan GF eyepiece. As the accompanying picture shows, the film plane would have originally sat some considerable distance above the photoeyepiece. Reducing this distance significantly, affects the quality of the projected image rather little, considering how far outside its original design parameters it must be operating. To adapt the unit for digital camera use I had an M45 to standard T-thread adapter made so that I could mount a range of different cameras via appropriate T-thread adapters.
The barrel of the photoeyepiece incorporates a zoom mechanism which is calibrated with the range X5 to X12.5. The whole item is solid and heavy and gives the impression of high quality engineering. I have mounted four different cameras to this eyepiece mounted on the 38mm phototube of a Leitz Ortholux 1 with a trinocular head. Two Canon dSLRs the 400D and 40D via a T-thread to EOS chipped adapter and two zoom compacts, a Canon G9 and a Nikon 5100 via threaded adapter tubes. The Canon dSLRs showed only marginal vignetting at the lowest zoom setting of X5. The two compacts showed significant vignetting at all zoom settings as might be expected, and 75%-100% optical zoom was necessary on these cameras to remove the vignetting leading in some cases to undesirable increases in magnification of the subject.
Image quality is good, especially with the dSLRS. Chromatic aberration is generally well controlled with objectives of the same manufacturer and vintage as the eyepiece such as Leitz NPlans and NPlanfluotars. With other objectives including those of the Leitz Ultropak incident light system, chromatic aberration can be more noticeable, but not so as to make the eyepiece unusable. Parfocality between the camera and eyepiece image is not quite perfect, but only small focussing adjustment is necessary. It is possible this could be modified by placing some extension between the Vario-Orthomat and camera. Once set at a fixed zoom setting, focus is quite well maintained with Leitz NPL objectives in the range X6.3 to X40, but focus across the zoom range with a single objective is not so well maintained and some refocusing is necessary. It would be interesting to see how bellows mounting the camera and reproducing the designed 300mm or so distance between the top of the eyepiece and the film plane would affect these parameters, but I do not have the facilities to do this.
The biggest advantage of this eyepiece is it’s wide zoom range from ‘wide angle’ at X5 to ‘telephoto’ at X12.5 with little loss of resolution. As forumite Hindpool has illustrated this offers significant flexibility in framing subjects and zooming into objects of interest.
To increase its flexibility Leitz (as Leica) produced a X0.1 C-mount adapter to allow the Orthomat camera to be replaced by a video camera with retention of the widefield view at low zoom. I have seen some very good results from such a setup owned by a fellow microscopist.
The accompanying pictures illustrate the original camera (courtesy of Hindpool) and the eyepiece itself.





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rjlittlefield
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Joined: 01 Aug 2006
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Location: Richland, Washington State, USA

PostPosted: Fri Oct 30, 2009 5:25 pm    Post subject: Reply with quote

What an interesting device! Custom optics and a custom film carrier as well.

Thanks for posting the description and images. I would have had no clue about this device otherwise.

As you hinted, I've moved this topic to Equipment. We generally reserve the image gallery "Photography Through the Microscope" for photos of microscopic subjects.

--Rik
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discomorphella



Joined: 01 Oct 2006
Posts: 605
Location: NW USA

PostPosted: Thu Nov 05, 2009 3:32 pm    Post subject: Reply with quote

Hi CactusDave and Rik--
I have 2 Vario-Orthomats and use both, one with a 0.1X / (unknown focal length) field lens to focus the image onto the CCD of a sony video camera, and the other with the 0.3X / 83.3 mm field lens to focus the eyepiece down to the CCD on my D200. The eyepiece does require an additional lens to take the "afocal" eyepiece image to a focussed image, you can use the lens on a fixed lens digital camera set to infinity focus (effectively taking the place of your eye's lens) or make an adapter for a DSLR (which I am still in the process of improving). The 35 mm film head comes with an 83 mm fl lens to do just that. I just removed that lens (it unscrews) for my own DSLR adapter. I suppose you could also get a nice achromat pair from edmund and make your own as well.
The variable zoom is very handy for doing video demos as you can just adjust it while standing next to the 'scope. It's also nice to be able to match your FOV through the eyepieces (e.g., say you are using a Periplan GW 8X) and the camera FOV.

FWIW--

David
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Cactusdave



Joined: 09 Jun 2009
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Location: Bromley, Kent, UK

PostPosted: Fri Nov 06, 2009 1:04 pm    Post subject: Reply with quote

Interesting David. I had heard of the X0.1 reducing lens for coupling to a C-mount videocamera, but the X0.3 field lens is new to me. I have not had the opportunity to disassemble an actual Orthomat camera myself, and I have not seen it offered for sale separately. The Orthomat does work satisfactorily with a DSLR without this lens, though of couse as I noted, it will be outside its design parameters in that case. How does the X0.3 attach? Does it screw directly onto the Vario-Orthomat itself or is there an intermediate tube? I would be interested in acquiring the X0.1 and X0.3 supplementary lenses to play with if anyone knows of a source.
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discomorphella



Joined: 01 Oct 2006
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PostPosted: Fri Nov 06, 2009 2:01 pm    Post subject: Reply with quote

Hi CactusDave--

If you get ahold of the 35 mm film holder the lens is built into the film back, basically to place a focussed image from the Vario zoom eyepiece onto the 35 mm film. In your photo it sits about at a plane in between numbers 3 and 4 on the diagramatic photograph. In general, if you operate without a final focussing lens you're effectively changing the tube length of the system, since the eyepiece is desgined to take the intermediate image from its front focal point, the rays come out of a standard eyepiece as parallel bundles. Your eye's lens focusses them onto your retina. Or something like that (since I have to wear glasses, its obviously not the same for me... Smile ). So for a regular eyepiece, you have to have another lens system in the path to get a parfocal image. You change the scope focus to compensate, but as you point out, this is using the objective/eyepiece combination outside of its usual design focal condition, and brings in spherical and other aberrations, to some degree. A photoeyepiece is designed differently. I will try to find the prescription information for the 83 mm / 0.3X lens, and maybe play with the optics simulator. We should be able to make a similar lens combination with some commercially available lenses. The vario is such a useful eyepiece its worth a try.

Regards.

Dave
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Cactusdave



Joined: 09 Jun 2009
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Location: Bromley, Kent, UK

PostPosted: Fri Nov 06, 2009 2:40 pm    Post subject: Reply with quote

Thanks for that information David. Those of us who use the Vario-Orthomat will look forward with interest to the results of your efforts. I think your understanding of the physics of optics considerably exceeds mine. Wink
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Charles Krebs



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PostPosted: Fri Nov 06, 2009 2:56 pm    Post subject: Reply with quote

Hi CactusDave and Dave,

Good thread and info. For me some points cross over into another discussion we've been having in a thread Graham started:
http://www.photomacrography.net/forum/viewtopic.php?t=8426

Not sure where to follow up with my questions, but since Dave hit directly on my "confusion", I'll proceed here. They are pertinent to this thread in that it may offer some thoughts about how to best use the Leitz Vario-Orthomat Variable Zoom Photoeyepiece in configurations different from the original.

Actually it's probably easiest to provide what is my current "understanding" and request any corrections or clarifications other can offer, so here goes...
_________

I'm not familiar with this piece of equipment. But I have often seen references to the Zeiss S-Kpl (and S-Pl) Graham discusses. I realize there is something of a "nomenclature" issue going on here with the term "photo eyepieces". The S-Kpl and this Leitz Vario-Orthomat were specifically designed to be used for photography. But they were not meant to be used "alone" as projection photo-eyepieces (like the Oly NFKs, which are a different animal). They are very highly corrected, but are designed to provide a "virtual" image, in that sense like a "viewing" eyepiece. When used for photography in the manner the designers intended, there is an additional optic involved between these eyepieces and the sensor/film. (Basically the "afocal" method. In principle like pointing a camera with lens attached into a "viewing" eyepiece, only with these pieces the optics are optimized and specifically made for this purpose).

Now any "viewing" eyepiece (including the S-Kpl and the Vario-Orthomat eyepiece) can be made to form ("project") a real image on the sensor/film without this additional optic by either "raising" it in the trinocular tube (higher than manufacturer intended) or by refocusing the microscope to bring the image into focus in the camera. Both of these methods have the possibility of introducing optical problems. In reality the problems introduced gradually become more objectionable as the numerical aperture of the system gets higher. At low NA not a big deal, but they could be very significant with something like a "high/dry" 40/0.95.
_________

Does this sound correct? If so it brings to mind some practical questions. What approach would provide best image quality overall? Would it be better if a lens were used on the camera, or as Dave suggested...
Quote:
I suppose you could also get a nice achromat pair from edmund and make your own as well.


Or would, in practical use, the re-focus or "raising" the eyepiece method be about the same? It would seem that with the Leitz Zoom piece it might be best to incorporate this additional optic if for no other reason than to keep the nifty "zoom" capability relatively "parfocal" and therefore of greater use.
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Hindpool



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PostPosted: Mon Nov 09, 2009 6:59 am    Post subject: Reply with quote

The Leitz Vario-Orthomat camera system being discussed in this excellent thread is, I believe, a more modern version of the "Leitz-Orthomat-W fully transistorized microscope camera for the 35 mm format" - as the Leitz brochure has it.

An Orthoplan I bought in France last August came with one of these microscope cameras, a very scruffy and apparently heavily used and cumbersome box of tricks that I put to one side until I had time to look into it. The controller was missing which rendered the camera unusable.

I could see that there was a photo lens but it was only removable by dismantling the camera and shifting a considerable amount of electronics - including an RCA 931-A vacuum tube. Eventually I had the lens out together with its complementary final focussing lens, as mentioned by Dave - Discomorphella. They appear to be excellent examples of Leitz optical design and manufacture.

A quick and dirty trial showed that an almost parfocal image might be obtained but I will have to use my copy stand as a vertical optical bench of sorts before starting lathe work on a permanent adapter. That will take some time but when possible I'll report back to the forum. Just don't hold your breath!

I wonder if anyone else has experience of the Orthomat-W? They come up on eBay now and then and may be worth acquiring.

Hindpool



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cephy



Joined: 11 Nov 2009
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PostPosted: Wed Nov 11, 2009 11:16 am    Post subject: Price Reply with quote

My lab is looking for a Vario-Orthomat setup for a dialux 22eb. What is the reasonable price for this (ebay?)?
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Hindpool



Joined: 01 Jun 2009
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PostPosted: Wed Nov 11, 2009 11:40 am    Post subject: Reply with quote

Cephy - as a recent member myself, welcome to this community!

I don't know if there are any current eBay offerings of the Vario-Orthomat but there are a couple available now from a personally recommended used equipment dealer in The Netherlands. Take a look at items 330 and 331 in ABRO's 'Diversen' section:

http://www.microscopen-specialist.nl/diversen

Although the website is in Dutch I assure you that the owner, Mr de Jong, speaks and emails in excellent English.

The prices asked, 350 Euros each, are typical I believe although you might find something less expensive on eBay, if you are prepared to wait.

Good luck!

Hindpool
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cephy



Joined: 11 Nov 2009
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PostPosted: Wed Nov 11, 2009 12:00 pm    Post subject: Reply with quote

Hindpool, thanks for suggesting that dealer. It looks like those 2 zooms came from different models of vario orthomat. I assume the one with 5x is the more recent one.

deleted: the thread has the answer of my question about the 0.3x lens.
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Hindpool



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PostPosted: Sun Nov 22, 2009 7:24 am    Post subject: Reply with quote

As a follow-up to earlier comments about the zoom photo lens from the Orthomat-W, a copy stand was used to make some trials with this old Leitz zoom mated to a Canon 450D dslr mounted on an Orthoplan. It proved possible to achieve a degree of parfocality but, as expected, not without sacrificing a great deal of the image as seen through the eyepieces. Introducing to the arrangement the focussing lens with which the Orthomat-W was originally paired improved matters in respect of image coverage but the focussing lens had to be positioned well above the zoom lens, making a rather unwieldy arrangement. Since the improvement in image coverage was still not ideal - the pair having been designed to cover the 35 mm camera format - the Orthomat-W was put to one side and its focussing lens used in conjunction with the more recent Vario-Orthomat, the original subject of this thread. Test shots led to the conclusion that the combination was basically incompatible.

The next step was to set up the Vario-Orthomat with the microscope on the copy stand as before to determine if parfocality could be achieved throughout the zoom range. It seemed that raising the zoom lens in the phototube would be a good place to start. A slightly over-long Delrin spacer was turned and reduced 1 mm at a time until the desired sweet spot was found at about 21mm length. This now provides spot-on parfocality and coverage by the camera sensor of a large portion of the field of view. It is the first time this desirable aim has been achieved with my Leitz equipment so the Orthoplan is now back on the microscope bench and I will try to get on with some photomicrography.

The following pictures show the Delrin spacer in use - there is just enough 'tail' left on the Vario-Orthomat for the rig to be secured by a screw through a tapped hole near the top of the photo tube. It is a perfectly stable arrangement like that.

The top picture from the combo that follows was taken with a Canon G9 shooting hand-held through the eyepiece; the lower shot shows the corresponding view recorded by the Canon 450D on top of the photo tube. No adjustments were made between shots. The rectangle is not quite the largest that could have been taken - that requires the Vario-Orthomat to be near the 6.3x setting - but the coverage is just about right for my purposes and far better that the fixed focal length photo lens I used before Cactus Dave introduced me to the Vario-Orthomat.

When holding the Canon G9 up to the eyepiece I was anxious to avoid visible camera shake on the photo so the camera was set to full aperture, f/2.8 and a high sensor sensitivity setting - 800 ISO. Looking at the shot at full size it struck me how little visible grain - noise in this era - was visible. A section from the unshrunken full-size frame follows the combo jpg and that tells its own story. This sort of performance far exceeds what I could achieve with fast film in the good(?) old wet darkroom days.

Those who started photography with a digital camera and have had no need to develop films and prints may not appreciate just how far things have advanced. I find it amazing!

Recently, a packet of various 'negative' lenses arrived from that wonderful resource Surplus Shed - about $20 worth and something of a bargain. In the light of how things stand now I am in no hurry to try them but will eventually do some some more fiddling around with the Orthoplan back on the copy stand.

Hindpool


Vario-Orthomat zoom lens with Delrin spacer


View through the eyepiece (top) and corresponding section from the camera sensor view


A full-size section of the eyepiece view, Canon G9 hand held, f/2.8 and 800 ISO
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Perl



Joined: 03 Oct 2006
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Location: Sweden

PostPosted: Sun Nov 22, 2009 12:49 pm    Post subject: Reply with quote

Hi

I have the 0.32 X flat lens for sale
taken from Orthomat assembly

Mail me offer offline

Regards
Pär Lundqvist
Sweden
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albertr



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PostPosted: Mon May 20, 2013 7:57 pm    Post subject: Reply with quote

I'm exploring the idea of mating Orthomat-W with a full-frame dSLR using relay lenses which are installed inside the Orthomat-W. Here's some pictures taken after removing film holder and cutting off its wires....






Also, was trying to project using an eye ocular installed in place of relay lenses, but in this case the results seem to be rather disappointing...





-albertr
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discomorphella



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PostPosted: Tue May 21, 2013 12:35 am    Post subject: Reply with quote

You have the right idea using the internal relay lens system and substituting the DSLR's CCD (or CMOS depending on the make of the camera) for the 35 mm film as your photosensor. You can't really use a regular eyepiece (occular) as your final element before the film, since eyepieces are designed to give an "afocal" (effectively focussed at infinity) image that your own relay lens, aka, your eye, can use to produce a final focussed image onto your retina...
The trick is to figure out (admittedly without any prescription data for the optics) where to place your DSLR. Ideally you would know the focal distance is from the final relay optic element to film plane, and then you would have a good starting point for where to place your film plane (aka camera) to get a nice parfocal image. Since I doubt that information is readily available (without rifling through ancient files at Leica...) you can measure (calipers carefully or ruler) and try to approximate the distance. You can also take advantage of what the optics guys call the front and rear telecentric points, which is a fancy way of saying, "if you put parallel rays into the back (front) of the lens you will focus to a point at the front (back) of the lens system at its focal point. This is in general true (with some caveats) for even the most complex lens systems and if you can get a nice collimated beam (say a laser pointer and a plano-concave lens of known focal length as a beam expander) you can put it into the the back (the scope end) of your Orthomat and see where it comes to a focus, and arrange to have your CCD at that distance (again, will be close depending on aberrations, and we are hoping Leitz didn't leave many of those in their final design, they are Leitz after all). You can also of course get a simple grating image as in a stage micrometer or something similar under your scope and see how high above your final elemement it comes to focus. However you arrange to hold the camera, do leave something, such as a set of concentric tubes and a set screw, or something more elaborate, so you can adjust the final camera height, as there are going to be some small effects that influence how parfocal your final setup is, and this way you can compensate for them.
Hope this is not too confusing.

David

edit: it does look like there are some mounting screw holes you could maybe take advantage of to fix a camera mount with some height adjustment to the final lens mount on top. I think that just holding your dSLR securely using a set of concentric tubes and a simple set screw should work for you. You'll just have to do a bit of tinkering / machining to get the camera held at the correct height.

edit: Basically this is the same procedure I used to find the focal distance for the 0.32X relay lens for the VarioOrthomat (the successor to the Orthomat). I carefully measured the distances from the film plane in the old film back to the 0.32X internal relay lens, verified it using the laser pointer and then machined a holder for the lens that held it at the correct distance from the CCD in the D300. The Vario-Orthomat eyepiece produces an afocal image that the 0.32X lens focusses onto the camera's CCD. The only difference with your Orthomat is the fixed magnification relay lens. See here
http://www.photomacrography.net/forum/viewtopic.php?t=10014&highlight=
for my example.
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