Breaking the baffling B & L Balplan buffalo.

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
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apochronaut
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Breaking the baffling B & L Balplan buffalo.

#1 Post by apochronaut » Mon Aug 29, 2016 11:55 pm

Yes, I know they were made in Rochester but for many years I, and I'm sure I'm not the only one, have been truly buffaloed by their objectives. They don't work in any other microscope nor do other microscope objectives work in a Balplan. This isn't too much of a hardship, because in a number of comparative tests I have done with Balplan achromats in a Balplan, against other contemporary achromats in appropriate stands, the Balplan objectives have always done as well or better. I have felt for a long time that B & L was doing something different, that gave their optics in the last 20 years of their production an edge. The colour correction of the last planachromats they produced is better than some fluorites made up until the 1990's.
Digging into some patents has provided a likely answer.
Bausch & Lomb , by the 1960's, realized that the going would be tough in the future. Japan was continuously upping their quality and had a distinct advantage in the cost of production, whereas Germany had always been competitive but still had a distinct edge on production costs.
At the time, a f.o.v. of 18mm was what most companies offered as wide field in the general market. To produce wider fields, with full edge correction was very expensive and generally could not be produced in a modestly priced lab instrument.
B & L had an answer and their answer, is the reason that their objectives are specific to only a few microscope stands.
They sought to produce a wide field, fully corrected microscope that was economic, by designing all the objectives in the system to take advantage of the same rear lens pack. This corrective lens was set apart from the middle lenses of the objectives by an air space and became a tube or telon lens situated above the nosepiece. Thus, the Balplan( as well as the earlier Dynoptic/Dynazoom flat field objectives) were actually semi-obectives of low magnification. What this allowed B & L to do was produce a series of very low magnification objectives of a more complex design than normal, with very high N.A.'s. The 100X objective for instance is actually a 20X 1.25 N.A. This low magnification and high N.A. allowed for superb curvature of field control, spherical and chromatic aberration correction, prior to the 5X magnification and correction trimming provided by the remote common rear element. The relatively gentle meniscus required for such modest initial magnifications, also allowed for flatter wider fields. B & L was able to offer 22mm at a time when most companies struggled to achieve 18mm and at competitive pricing .
Over the 25 or so years that this design existed, they produced several ranges of semi-objectives. The first were flat field achromats, flat field fluorites and flat field apochromats followed eventually by much improved planachromats, that were so good that they ceased production of the flat field fluorites. There was also at least one planfluorite, a 50X .80 oil immersion.
The actual magnification of the objectives is 1/5 of the marked value but the N.A., is that, that is marked. The large relative size of the objectives allowed for very wide fields and superior correction without having to resort to very expensive glass formulations , the highly difficult grinding of extreme curvatures and more complex lens formulae.
Attachments
Side view of the basic 20 watt halogen stand.
Side view of the basic 20 watt halogen stand.
DSC01842 (1024x896).jpg (201.28 KiB) Viewed 3789 times
Front view of the basic 20 watt halogen  phase contrast instrument. There were many permutations, including vertical DIC, 100 watt research stands and pol
Front view of the basic 20 watt halogen phase contrast instrument. There were many permutations, including vertical DIC, 100 watt research stands and pol
DSC01844 (575x1024).jpg (147.41 KiB) Viewed 3789 times
A set of phase contrast objectives; 10X .25, 20X .50 , 40X .65 and 100X 1.25 planachromats flanked by a conventional 97X 1.30 B & L 160mm objective on the left and a couple of D.I.N. objectives on the right.
A set of phase contrast objectives; 10X .25, 20X .50 , 40X .65 and 100X 1.25 planachromats flanked by a conventional 97X 1.30 B & L 160mm objective on the left and a couple of D.I.N. objectives on the right.
DSC01845 (1024x562).jpg (167.45 KiB) Viewed 3789 times
2.5X, 4X and 100X 1.25 iris planachromats, flanked by a conventional B & L 97X 1.3 160mm objective on the left and a Jena D.I.N. objective on the right for comparison.
2.5X, 4X and 100X 1.25 iris planachromats, flanked by a conventional B & L 97X 1.3 160mm objective on the left and a Jena D.I.N. objective on the right for comparison.
DSC01846 (1024x564).jpg (157.67 KiB) Viewed 3789 times
7.5X .20 , 25X .65 , 50X .80 oil (planfluorite) , 75X 1.20 oil and 125X 1.4 oil  flat field apochromats flanked by a conventional B & L 97X 1.3 160mm objective on the left and a Jena D.I.N. objective on the right for comparison.
7.5X .20 , 25X .65 , 50X .80 oil (planfluorite) , 75X 1.20 oil and 125X 1.4 oil flat field apochromats flanked by a conventional B & L 97X 1.3 160mm objective on the left and a Jena D.I.N. objective on the right for comparison.
DSC01847 (1024x562).jpg (161.88 KiB) Viewed 3789 times
Last edited by apochronaut on Sun Jan 22, 2017 8:05 pm, edited 1 time in total.

JimT
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Re: Breaking the baffling B & L Balplan buffalo.

#2 Post by JimT » Tue Aug 30, 2016 10:30 pm

Interesting instrument. B&L also acquired Criterion Telescope Co. in the early 80's.

They switched to eye health products; lenses, contacts, implants, etc. Acquired in the mid 2000's.

I know this because I live in Rochester.

A little extra history :)

JimT

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Re: Breaking the baffling B & L Balplan buffalo.

#3 Post by apochronaut » Wed Aug 31, 2016 1:47 am

thanks.
You could be potentially inundated with the history of optical development, living in Rochester, JIm. Some of the finest innovations in optics stem from those environs.
The microscope business of B & L became a separate enterprise of the parent company, sometime in the 1960's, I think it was. It was called the Scientific Optical Products Division. Once they patented the soft contact lens: that provided the payroll of the company and the Scientific Optical Products Division a bit of a sideshow for them. They really didn't need the microscope business because based on their Opthalmic business they became a highly profitable Fortune 500 company. I think the option to sell off the Scientific Products Division to Cambridge Instruments in 1984 was a win win situation. Cambridge needed to expand their scientific optical business and B & L needed to focus on Opthalmics, which was highly lucrative.
However, they did make fine microscopes nontheless and contributed greatly to the advancement of microscope technology. Navitar and Hoffman Modulation Optics certainly carry on Rochester's enviable tradition of innovation.
Here are a couple of front and rear pictures of the B & L objectives. Oddly, they do not look like partial objectives, they look like finished objectives but the part has been brought to such a high degree of refinement that it goes unnoticed. The 75X objective, looks like a 75X objective in the pictures( as do the others look their part) but it is actually a finely corrected 15X 1.20 N.A. oil immersion flat field apochromat waiting to be coupled to a 5X remote correcting rear element in the optical tube. The resulting image quality of the combined optical system is very fine, indeed. Nobody, had better microscope imaging in it's time.....flat field, exceptional colour correction, exceptional spherical aberration correction and wonder of wonders for the mid-70's a 22mm f.o.v. in a reasonably priced lab microscope.
Attachments
Balplan semi-objectives 4X( actually .8X .09) planachromat, 25X ( actually, 5X .65) flat field apochromat, 75X( actually, 15X 1.20 oil) flat field apochromat and 20X ( actually 4X .50) flat field phase achromat.  Front view.
Balplan semi-objectives 4X( actually .8X .09) planachromat, 25X ( actually, 5X .65) flat field apochromat, 75X( actually, 15X 1.20 oil) flat field apochromat and 20X ( actually 4X .50) flat field phase achromat. Front view.
DSC01849 (1024x547).jpg (154.92 KiB) Viewed 3748 times
The same as above ; rear view.
The same as above ; rear view.
DSC01848 (1024x555).jpg (157.79 KiB) Viewed 3748 times

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Re: Breaking the baffling B & L Balplan buffalo.

#4 Post by billben74 » Wed Aug 31, 2016 9:31 am

Keep them coming. We all love microscopes and learning more about them.
Many thanks.

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Re: Breaking the baffling B & L Balplan buffalo.

#5 Post by apochronaut » Wed Aug 31, 2016 12:05 pm

One other interesting design feature that Bausch & Lomb incorporated into their objectives, going back into the 40's is ease of parfocality. Objectives could have slight manufacturing differences, so parfocality although close, might not be dead on.
Each objective B & L made , has adjustable parfocality. If you look at the 4 gold flat field apochromat objectives pictured above, and as well, the older 97X 1.30 achromat to the left of the first vertical group shots, you will see a small seam, between the knurled grip ring section and the objective shroud. You will see that the gap is wider on some objectives than on others. The shroud is actually a threaded cap over the nose section of the objective. By loosening or tightening the rear diaphragm and lock ring on each objective and simultaneously loosening or tightening the shroud on it's fine thread, you can move the actual entire objective lens pack back and forth relative to the objective body, to obtain perfect parfocality between objectives.
The later objectives, such as the planachromats and planfluorite pictured, which are not designed with a shroud, have a small cam built in, actuated by a small screw, that moves the lens pack back and forth relative to the objective body, in order to get precision parfocality. You can see the mechanism clearly, in pictures 3 and 4 on the two red 100X planachromats.
Last edited by apochronaut on Sun Jan 22, 2017 8:10 pm, edited 1 time in total.

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Re: Breaking the baffling B & L Balplan buffalo.

#6 Post by zzffnn » Wed Aug 31, 2016 6:00 pm

Thank you, Apo, for this informative thread.

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Re: Breaking the baffling B & L Balplan buffalo.

#7 Post by apochronaut » Wed Aug 31, 2016 10:59 pm

Thank you, Fan.

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Re: Breaking the baffling B & L Balplan buffalo.

#8 Post by wporter » Tue Jul 10, 2018 3:11 pm

Trying to rejuvenate a Balplan, I found this thread very illuminating. Thanks to Apo for once again for giving us a brain-dump from his extensive study of objectives.

Apo, if I understand it correctly, the planachromats were the last and best of the Balplan-compatible objectives, so there is no practical sense in hunting down apochromats for the scope, unless they just drop into your lap, so to speak. Is this correct?

Below is an image of five Balplan objectives. So the PA version of the 100x is upgraded from the flat-field variety? And I see that even the 10x planachromat phase has a different barrel from the 10x non-phase planachromat; interesting.

Any comments welcome.
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Re: Breaking the baffling B & L Balplan buffalo.

#9 Post by apochronaut » Wed Jul 11, 2018 11:34 am

The first ones were for the Dynoptic and Dynazoom but only for those microscopes with
the words Flat Field printed boldly across the front of the head. I've
seen a 100x 1.30 Flat Field Fluorite, that was physically similar to the
last U.S.A. made 160mm objective series from B & L, just larger, with no
160 written on it and Flat Field clearly marked. There were most likely
achromats like that too but B & L may have had trouble with people
understanding that the Flat Field and 160mm objectives were for mutually
exclusive instruments, so the physical format of the barrels was dramatically changed early on.
The first clearly different Flat Field objectives were those with large
straight sided barrels but with a small knurled ring near the base.
Polished chrome barrels for the achromats and fluorites and polished
brass for the apochromats. For DF you have to replace the rear diaphragm
with one of smaller diameter for the high N.A. objectives.
I know of 4x .09, 10x .25, 40x .65 and 100x 1.25 oil as achromats : 50x
.80 and 100x 1.30 oil as fluorites and 7.5x .20, 12.5x .30, 25x .65, 75x
1.2 oil and 125x 1.40 oil as apochromats. I'm pretty sure there were also
40x .85 and 100x 1.30 oil apochromats as well.

Some of those Flat Field objectives were carried forward into the Balplan
> program and some were not but they are all made with the same
> corrections, so any work fine. I think what happened , is that they decided to
> upgrade the program and deleted those that either weren't in their plans
> or needed technical upgrading.
> To complicate things further, they changed the barrels into ones with a
> more convoluted shape with a large central knurled ring, yet retained the Flat Field
nomenclature. B & L has always had an internal parfocalizing adjustment,
so with the newer barrels they incorporated an internal cam,
actuated by a small screw in the side.
Some of those , mainly in lower magnifications; 10x and 20x with the newer
barrel shape can be found still marked Flat Field, while others are marked
Planachromat.
It's possible that for some objectives they just brought some of the same
designs forward into the newer barrels and decided that Flat Field was no
longer as useful a marketing nomenclature and switched to Planachromat instead
but it seems likely that two newer style barrels exist, one as a Flat Field and
one as a Planachromat.
> I have never seen a 100x in the newer shaped barrel that is marked
> Flat Field and in tests, the 100x 1.25 oil Planachromat, is a noticeably
> better objective than an older 100x 1.25 oil Flat Field Achromat. However,
I see that you have both a Flat Field and a Planachromat in the newer barrels.
albeit , slightly different ones.
I would be interested to know your impressions of the differences in them.
> At the time that the newer barrels came out they also seem to have
> deleted the older straight sided fluorites. One re-engineered fluorite I
> know of for sure is a 50X .85 oil planfluorite in the new style barrel,
with parfocalizing cam.
> The newer planachromats are so good that they are better than the earlier
> straight sided Flat Field fluorites, displaying very little if any chroma
> in tiny, normally diffractive spaces. The 50x Planfluorite must have been
considerably inproved, in order to fit well with the Planachromats and indeed it is.
> However the reason for the deletion of the higher magnification Flat
> Field Apochromats is probably somewhat different because they are all
> excellent, displaying very fine flat field apo quality. The N.A.'s alone ,
indicate that.
The dovetail for the condenser of the Balplan is distinctly
> different from that of the Dyna series and they had not yet redesigned a
> high N.A. achromatic/ aplanatic condenser yet for the Balplan. It was
> probably left to near the end of the development list. I'm pretty sure
> that they had plans to refine the Flat Field Apochromat series originally
> for the future but by the time they had refined the bread and butter
> stuff, the entire program was in jeapardy due to new ownership and an
> entirely different consolidated stocklist. First for Cambridge
> Instruments and later the Cambridge/Wild-Leitz merger. The Balplan just
> wasn't needed. All they ever listed in the 70's catalogues as apochromats
for the Balplan were the 7.5x .20, 12.5x .30 and 25x .65 and seemingly
entirely unchanged from the objectives that were made for the Dyna series.
The pictures look identical to the objectives made for the Dyna series but
they are listed as Planapochromats. I suspect that they are the Flat Field Apochromats
> rebranded. I have never seen a Planapochromat, except in the catalogues.
All of mine ( 7.5x,25x,75x and 125x) are marked Flat Field Apochromat.
> In later literature the apochromats are not mentioned at all. They possibly did
> not sell well, due to cost; another nail in the Balplan coffin.
> Another omission in catalogues is the is the 50X .85 oil planfluorite.
I have one of those and have seen one other but it shows up in not one of the
6 trade catalogues or price lists printed between 1975 and 1986 that I have,
devoted to the Balplan. Beginning in the Oct.1 1977 price list cat.# 31-12-25,
a 50X .85 planachromat shows up but it is gone by 1986. I have not ever seen one of those.
>
> So, it is safe to say that the more slender design Planachromats 2.5X
> .06, 4X .09, 10X .25, 10X .25 L.W.D., 20X .50, 40X .65, 100x 1.25 oil and
> 100X 1.25 oil with iris are of superior performance, with resolution and
> contrast noticeably better than the older straight barreled Flat Field
> Achromats. I have trialled two entire sets; 4x,10x,40x and 100x against
each other and the Planachromats are superior in all ways , visually.
Presumably the 50x Planachromat oil would be as well and of course
50X .85 Planfluorite. Personally, I wouldn't bother with older Flat Field
> Fluorites( if you can find one), although for a good price, one or more
> would certainly be better than the older Achromats.
> All of the Flat Field Apochromats are worth while but scarce as scarce
> can be. I'm still in the design stages of working an achromatic high N.A.
> condenser into a Balplan housing for the 75X 1.2 and the 125X 1.4 oil
Flat Field Apochromats.

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Re: Breaking the baffling B & L Balplan buffalo.

#10 Post by apochronaut » Thu Jul 12, 2018 12:52 pm

The earliest objectives for the program referenced above, looked like this.
https://www.ebay.com/itm/MICROSCOPE-PAR ... xyx0JTiTKM

That one is a metallurgical version but the early flat field fluorite, corrected for a .18 cover, that I once had looked almost identical and was spring loaded too. Later objectives, lacked the spring loading. The telescope lens used in the instrument appears to be the same for all objectives, diascopic, episcopic and met. The epi objectives, were slightly larger, with a 25mm thread. They work in the standard nosepiece, when fitted with an adapter but they get a little long. I have an 80X .90 flat field fluorite epi, which is a really superb no cover objective.

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Re: Breaking the baffling B & L Balplan buffalo.

#11 Post by Hobbyst46 » Thu Jul 12, 2018 3:27 pm

Reading this very informative review I remembered to have read a statement about interchangeability some time ago on this respected forum - and found it!
apochronaut wrote:Interchangeability, despite the fact that in theory it was promoted by the RMS and others over many years, has never really existed anyway. Leitz, and a few others never conformed obviously, and when you factor in the necessity with most 160mm systems to employ proprietary eyepieces and the differences in parfocal distance with many, it has always been a bit of a myth....The optics are outstanding. The planachromats perform like planfluorites.
I learned it the somewhat hard way: on a finite TL microscope, mixing Zeiss objectives with Olympus eyepieces, or vice versa, works fine - as long as the judge is eye vision alone. The camera demonstrates the CA problems.
The happy news is that on modern, infinity corrected microscopes, even the objective thread differs among brands, so any pretensions :oops: :? about interchangeability are spared...
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

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Re: Breaking the baffling B & L Balplan buffalo.

#12 Post by wporter » Thu Jul 12, 2018 6:07 pm

Apo, thanks for the writeup; exhaustive as usual, and much appreciated by us objective hunters. You also bring home the chaos that must have overwhelmed the microscope industry during the last quarter of the 20th century.

As far as the two 100x objectives (the slightly different new-style barrels, one 'flat-field', the other 'planachromat' in my image above), they seem to perform pretty much the same; perhaps the planachromat is very slightly better.

Your point about needing the correct eyepieces is one that needs stressing, especially to beginners, and especially involving unusual microscope designs, such as the Balplan. The one I am fixing up came with two B&L eyepieces, marked only 10x W.F., silver with a black & brass slotted retaining ring at the top (eye lens); turned out to be very inferior to the proper eyepieces I obtained later, the kind marked 31-15-61, 10x W.F.

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Re: Breaking the baffling B & L Balplan buffalo.

#13 Post by apochronaut » Thu Jul 12, 2018 9:32 pm

Thanks, Bill. In looking at your pictures, I suspect that 100X flat field achromat you have, with the more recent " slender nose design" ( I guess that is about as good as I can dub it), doesn't have the little set screw and cam mechanism with which to parfocalize it? It probably used the old B & L system of sliding the lens pack back and forth in the barrel..
I see that it has a seam near the bottom of the larger diameter section of the barrel. When that section is unthreaded slightly, you should be able to turn the rear diaphragm in with a pin spanner, circlip pliers or other device, driving the lens pack farther down in the barrel. Thus, by loosening or tightening that lower section , along with tightening or loosening the rear diaphragm, the entire lens pack can be moved up or down in the barrel relative to the nosepiece, affecting it's parfocal distance.

With the older broad, straight barrel types, that big outer shroud is loosened with ones hand, and then the rear diaphragm tightened to lower the lens pack and the reverse to raise it.
If you look at the picture of my flat field apochromats with the one older 97X 1.30 B & L 160mm tube objective on the left, the 50X .80 oil planfluorite in the middle and the D.I.N. Jena 100x 1.25 objective on the right, you can see that the seam in the middle of the objective barrels of the apochromats varies in width. That seam widens or narrows, based on how they are parfocalized. The 97X, also has a gap at the top of the shroud, next to the knurled section. That gap can be closed right tight with a certain parfocal adjustment, or even be a bit wider than it sits in the picture. On the 50X .80 planfluorite, you can just barely make out the locking screw for the parfocalizing cam, on it's left side.

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Re: Breaking the baffling B & L Balplan buffalo.

#14 Post by lrak » Thu May 21, 2020 5:31 am

Excellent story about the confusing optics - those optics sent me on a confused path many years ago when I had to add a lens to a metal camera tube (one we turned on a lathe) for the Balplan with the trinocular head.

I have a couple of Balplans - one of them is a B.f./D.F which to me is priceless. (I mostly use this scope for looking at metal).

I think the BF/DF version also uses the "semi objective' approach - not entirely sure?

The used price of these scopes has gone up quite a bit in the last years..

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Re: Breaking the baffling B & L Balplan buffalo.

#15 Post by apochronaut » Thu May 21, 2020 11:44 am

Welcome Balplan enthusiast. I think I have used an upload of yours in the past?? How strange that a Balplan enthusiast should pop up just at the time I start a thread about objective upgrades, since with the exception of effecting a complete overhaul of the optics , it is impossible to use another brand's optics in a Balplan. I agree, Balplans are priceless and have become pricier lately. I still see what look like pretty good ones in the $200.00's though, sometimes.Their build quality is very fine. One doesn't often hear about someone facing serious problems with their mechanics. It is always about the problem of the optics; sometimes about de-lamination but mostly about : Why won't this objective work on my XXXX microscope or why won't my XXXX objective work on a Balplan.
That latter relates straight back to yesterday's thread. viewtopic.php?f=5&t=9434&p=80737#p80737

Balplans are in fact infinity corrected, it is just that the back lens of each objective is common to them all, so the objective shoulder ends up \ not being in the nosepiece, it is in the arm of the microscope. From there it is infinity and the telan( tube) lens is in the monocular or more usually, binocular head.

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Re: Breaking the baffling B & L Balplan buffalo.

#16 Post by geo_man » Sun May 24, 2020 7:54 pm

These Balplans sound very interesting. I noticed the strong similarity of the stand with my SZ7 R Stand, which seems very nicely designed and built. I also noticed that many of the Balplans on eBay are missing their condenser, I wondered why that was so. Cheers!

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Re: Breaking the baffling B & L Balplan buffalo.

#17 Post by Scarodactyl » Sun May 24, 2020 9:58 pm

Are microzoom objectives cross-compatible? Many parts seem to be balplan or balplan-adjacent on those.

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Re: Breaking the baffling B & L Balplan buffalo.

#18 Post by apochronaut » Sun May 24, 2020 11:06 pm

Geoman. The reason for the similarity in the two stands is based on an economy of scale. The same base and electronics are used in both and the construction of the unit is first rate. It was also used for the Microzoom. Bausch & Lomb had evolved to the point of using the model builder concept for their Rochester made microscopes, with the Balplan, Stereozoom and Microzoom programs, although the model builder charts are specific to each type of scope.

Scarodactyl. The Microzoom is an adaption of the Dynazoom , kind of fused with the Balplan. I have not tried any Microzoom objectives in a Balplan. I'm guessing they might be hard get room to focus. Maybe that U.L.W.D. 50X could. The Microzoom does have that negative lens up above the nosepiece, so I am pretty sure that the principal is the same, if not the totality of the optical system. Using objectives from one in the other might just be a question of the focal distance. I have used a MET objective from the era in a Balplan but it is marked 211 total length on it. The only reason was that it was really inexpensive and it is hard to turn down dry 80X .90 Flat Field Fluorite. It's 24mm but I got an adapter from Raffi and it works like a charm on a Balplan. It is entirely possible that the Balplan does have a tube of 211mm total length; just broken up into the segments that comprise it's optical tube.

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Re: Breaking the baffling B & L Balplan buffalo.

#19 Post by BramHuntingNematodes » Mon May 25, 2020 1:36 am

It would be fun to have a dedicated balplan for phase microscopy, but I don't know where I could find the lenses. Yours are I think the only ones I've even seen pictures of.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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Re: Breaking the baffling B & L Balplan buffalo.

#20 Post by apochronaut » Mon May 25, 2020 10:40 am

I Miller ( micoscope central) has some. They were the biggest Balplan dealer, probably. However the expertise related to their assessment of their old stock isn't the best in my experience. Perhaps I ask too much but I expect things to work as they should.

There was a set being sold from Eastern Europe a while back and it just went off ebay. It was 100.00 or so and once or twice I contemplated buying it but then logic kicked in and mentioned that I already have one! It sat there for weeks, though. Anyway, I will keep a look out. There definitely are objectives out there. The system is a very good phase system; about on a par with the AO series 400 versions. It is only dark. B & L did not invest as much in phase systems as AO.
Both of those companies, in comparison to their 4 major competitors were very small scientific divisions of much larger companies that were mostly involved in opthalmics. B & L jettisoned their scientific division somewhere in the early 80's and concentrating almost exclusively on contact lenses, has become a Fortune 500 company.
From a business standpoint, selling off theose microscope businesses was very sound but also lamentable for those interested in microscopes because they were making first rate equipment and I'm sure had some interesting stuff in the pipeline. At AO, they had prototype Hoffman Contrast systems done and functional for instance, something that only marginally saw the light of day. They faced an ever steepening uphill battle though, trying to outcompete companies that benefited from slack labour laws, subsidies and trade protectionism.

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Re: Breaking the baffling B & L Balplan buffalo.

#21 Post by BramHuntingNematodes » Mon May 25, 2020 4:44 pm

Thanks friend. How would you describe your feelings on the dynazoom platform?
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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Re: Breaking the baffling B & L Balplan buffalo.

#22 Post by apochronaut » Tue May 26, 2020 12:55 am

I've fancied buying a Dynazoom for a long time but never did. There is no real reason why, just that I was hoping to find a tricked out version. Never did.

First of all, there are two Dynazoom systems. The standard or older ones used the last Rochester made 160mm tube system. There were no plan optics and the technology was advanced versions of basically 40's designs. Coating was the main +, although the B & L 160mm stuff in the 50's and into the 60's was really good.
The Flat Field Dynazoom was a whole other thing. Fields were 20mm, and flat. There were Flat Field Fluorite and Apochromats. There was a really nice 1.4 N.A, achromat/aplanat condenser with oblique and a 2X zoom head. That 75X 1.2 N.A. flat field apochromat could be tweaked to 1200X with the turn of a dial. The 125X 1.4 N.A. to 1400X . There is a lot to like in the concept. I never found one fitted out well, though. Almost all have pretty pedestrian Flat Field achromats and 1.30 abbe condensers. Those early flat field achromats were greatly upgraded , when the Planachromats came out around 1974-5. I would think if you could find a really nice one at a good price, it would be worth building on. Those objectives with the higher level of colour correction are really hard to find though, and there was that era when they faced a lot of cement degradation, so objectives must be chosen carefully. It does seem that once an objective has made it this far, that it is good to go for a while , though.

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Re: Breaking the baffling B & L Balplan buffalo.

#23 Post by BramHuntingNematodes » Tue May 26, 2020 6:14 pm

Thank you Apo. I had my eye on an attractive looking model and have since bought it after you had nothing audaciously negative to say about it. It has the plain flat field objectives, and I can't really tell what exactly is going on with the substage until I get it, but it does have this massive trinocular photo tube made by B&L. In addition, and this is the most important, it is black to match my Dynoptic.

Microscope Central has one fluorite and one apo flat field. I inquired as to the price, but fear I may have angered someone over there as I saw a Balplan darkfield condenser being advertised for $0 and naturally bought it. Of course it was a mistake (or I would definitely be getting one of those stripped down Balplans one sees).
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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Re: Breaking the baffling B & L Balplan buffalo.

#24 Post by apochronaut » Tue May 26, 2020 10:12 pm

The 7.5X flat field apochromat is a really nice objective but I'm thinking they will want 175.00-225.00 for it. The 50X flat field fluorite they will want 125.00 -160.00 for. They also have a box full of 12.5X flat field apochromats with varying degrees of de-lamination affecting them. The last I heard they had possible visions of refurbishing them with heat but the Balplan market is fading away, so they should be giving them away.

So, the 50X flat field fluorite I am familiar with, and it is not significantly superior to the 40x .65 planachromat to be worth chasing after. The upgraded version of that was the 50X planfluorite oil. pictured wedged between the flat field apochromats in picture 5 above. It is a superior objective and I would keep my eye open for one. Definitely a plus objective , when stepping back from any oil immersion high resolution work, for a broader view. It's pedestrian N.A. of .80 will work in DF. I am not sure that the 50X .85 dry flat field fluorite will and I don't think they made DF diaphragms for those.

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Re: Breaking the baffling B & L Balplan buffalo.

#25 Post by BramHuntingNematodes » Wed May 27, 2020 1:54 am

Hmm. I am a little confused. Are the planachromat lenses that work on the Balplan compatible with the flat field dynazoom? If so, are special eyepieces required or are the corrections/ additional magnification s performed in the tube?
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Re: Breaking the baffling B & L Balplan buffalo.

#26 Post by apochronaut » Wed May 27, 2020 2:05 am

Yes. Flat field and plan objectives are all good for Flat Field Dynoptic, Flat Field Dynazoom and Balplans. With the plan series of objectives they had the benefit of improved glass, coatings and ray tracing, so they are quite a bit better in all ways.

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Re: Breaking the baffling B & L Balplan buffalo.

#27 Post by BramHuntingNematodes » Wed May 27, 2020 3:01 am

Wow, fantastic news! I will wait until I have it in hand before getting too excited-- there are flat field objectives on it, but who knows from where. They've also got the nosepiece turned around, so I can't see the inscription or lack thereof. On the other hand, they weren't asking for enough money to really inspire deception.

So why were the special eyepieces needed for the Balplan only? What else is in its mysterious optic train?
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Re: Breaking the baffling B & L Balplan buffalo.

#28 Post by apochronaut » Wed May 27, 2020 11:27 am

Flat field are 99.99999% likely to be B & L. The only others that I know of that broadcast that on the barrel are Meiji, and they would no even make an image when put on a B & L flat field microscope.

The older flat field corrected eyepieces were marked 10X W.F. 23. They have an 18mm f.o.v. The 20mm verison of those came later and are usually marked with a cat. # 31-15-61 as well as 10X W.F. They both have the same corrections and work equally well with the flat field and plan objectives ( not the 160mm plan). However, the Dyna series of microscopes were originally configured for an 18mm f.o.v., so they might not support a 20mm f.o.v., if one were to use those eyepieces. There could be vignetting at high magnifications. Using the Flat Field objectives in a Balplan, they have an ever so slight peripheral distortion and ca at 20mm, another plus for the planachromat objectives.

There is another very similar silver eyepiece to be avoided for the flat field and plan objectives. It is longer than either of the above and has mistakenly been marketed on ebay as having a 22mm f.o.v. because it is marked 10X W.F. 22. The 22 refers to the eye relief, not the f.o.v. It is configured for the last Rochester made B & L 160mm objectives used on the non flat field Dyna microscopes and produces an undesirable level of off axis ca and coma when used with the flat field and plan objectives.

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Re: Breaking the baffling B & L Balplan buffalo.

#29 Post by BramHuntingNematodes » Sun May 31, 2020 2:52 pm

apochronaut wrote:
Wed May 27, 2020 11:27 am
Flat field are 99.99999% likely to be B & L. The only others that I know of that broadcast that on the barrel are Meiji, and they would no even make an image when put on a B & L flat field microscope.
The objectives are fine, I was more worried that head would not be a flat field version-- but it is! What a superb microscope. Big and heavy, it makes my pigeon-breast Dynoptic look almost miniature. The eyepieces are silver, marked only with 10x W.F. and the B&L in a kind of vermilion. They are easily the widest lensed eyepieces I have ever used. What a big field! I had no idea. Also, I like that I was able to make many "precision" adjustments to the optical path with a screwdriver and some pulling on a piece here and there. The construction is very straightforward with as few large, solid dumb hunks of metal used in the most straightforward fashion. The high intensity illuminator is missing its bulb receptacle, cord and transformer, but is otherwise intact. Sounds like a job for an LED retrofit. The zoom feature could be very handy in hunting live microbes, It works perfectly.

The bad and good news is that while the 10x obj produced a reasonable image, the 40x did not. Close inspection has led me not to the objective, but to a severely milked over delamination in the EF lens immediately in front of the nose:
http://www.quekett.org/wp-content/uploa ... ctions.pdf

This is not so bad, as this is a loose negative achromat doublet that is easily accessible after removing the nosepiece and spilling all of the ball bearings onto the floor (I recovered all but one). Visual inspection suggests that all the other lenses are clear-- a relief since they are all much more difficult to get to. I have put out for a small dropper of Norland 61. One question: I have been having some difficulty in finding methylene chloride. Is the easily available dimethyl carbonate/ methyl sulfoxide substitute do any good or will it damage the lens elements? Do either of these chemical solutions preserve the optical coating?
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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Re: Breaking the baffling B & L Balplan buffalo.

#30 Post by Hobbyst46 » Sun May 31, 2020 4:53 pm

BramHuntingNematodes wrote:
Sun May 31, 2020 2:52 pm
...One question: I have been having some difficulty in finding methylene chloride. Is the easily available dimethyl carbonate/ methyl sulfoxide substitute do any good or will it damage the lens elements? Do either of these chemical solutions preserve the optical coating?
Methylene chloride is harmful, not benign. It is very volatile - much more so than acetone, for example - and heavy! if you pick some of it with a pipette, it flows out uncontrolled from the tip. It is hydrophobic (does not mix with water) and a good to excellent solvent for adhesives and oil. If and when using it (do not, unless you must!) - work in a fume hood and wear heavy rubber gloves.
Dimethyl sulfoxide and dimethyl carbonate are very different from methylene chloride. They are fairly non-volatile, hydrophylic (mix well with water), and are good solvents for other substances than oil - although they can dissolve many organic chemicals. When using them, wear nitrile gloves.
Ordinarilly, I would not consider any of them to be an alternative for methylene chloride.
So, the question is, what is the application you envisage for any of these solvents ?
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

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