Older B&L microscope question

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GOLGO13
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Older B&L microscope question

#1 Post by GOLGO13 » Sun Jan 27, 2019 4:42 pm

I am new to microscopy and picked up a classic B&L compound microscope (pictured below).

My question is, am I missing anything using a scope of this age? I believe it is from the 1950s + or - 10 years.

Everything seems to work well so it's more about any changes in optics etc.

Image

billbillt
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Re: Older B&L microscope question

#2 Post by billbillt » Sun Jan 27, 2019 5:06 pm

LOOKS FINE TO ME...

apatientspider
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Re: Older B&L microscope question

#3 Post by apatientspider » Sun Jan 27, 2019 5:48 pm

That is a classic Dynoptic from about 1960, and you are very fortunate to have one with the trinocular head; that is unusual. I have the binocular model. Most of my scopes are old black beauty Spencers or American Opticals, but I do own one of these Bausch and Lomb lab scopes. It was or is a great microscope, I think. It uses 160 mm tube length optics, so you can always upgrade to other manufacturer's optics easily, if you wish. But actually there are still plenty of used B & L lenses and various accessories left out there on auction sites - at least in the US. You can even still find apochromat objectives for it.

Many of the advances that are available in modern optics have been made since the advent of infinity corrected systems, including those made by B&L. So most of any shortcomings would be due to the use of the older finite 160 mm tube length lenses - usually not much of a limitation, I don't think.

Other possible limitations the Dynoptics might have would be due to different design elements compared to more modern scopes. For example, there is no provision for built-in illumination - a separate lamp is used with a mirror, although some of us out here consider that an advantage to older microscopes. Another might be the fact that the head does not rotate to a different orientation, but I suppose it all depends on what one is used to - or gets used to.

That's a great microscope! I think you will find that for hobbyist use it will do pretty much anything you might ask of a scope.

Jim

apochronaut
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Re: Older B&L microscope question

#4 Post by apochronaut » Sun Jan 27, 2019 6:18 pm

That is actually a good choice, especially if you didn't pay too high for it. It was the last horseshoe based B & L that could be fully outfitted for research purposes and it came with the uncommon trinocular head too. With that photo tube, it will be easy to set up couplings for a small digital camera. Those are great little scopes with a low fine focus. The optics are first rate for their time.

The illuminator( a Dickson) gives it about as much versatility as a scope with a built in one. It appears to have a centering condenser, which is good. You will be able to find other condensers to fit in there, dark field or one of the B & L achromat/aplanats. Those show up on ebay for low $, quite frequently. Also, B & L made a fluorite 43X 1.0 oil immersion, as well as a complete stable of apochromats for that. They also come up on ebay for low $ fairly frequently. It may not have the right eyepieces. There were quite a few choices but those may be from either a B & L stereo or the later series of flatfield scopes. They will work but the edges of the field might show too much curvature of field and or undesirable levels of chroma. The correct ones are available , again for low $. There will be a # on your eyepieces, likely. That # will tell whether they are the right ones or not for those objectives.

B & L , like most mfg. of that day, did not make plan objectives, however they were attentive to wide field requirements as well as the planarity of their systems. They produced a line of eyepieces that were called "hyperplane". These correct somewhat for the natural curvature of field and edge distortions of the objectives and yield a reasonably plan field, that is wider than normal. True wide field eyepieces also exist but do not yield a flat field.
You will see B & L flat field and planachromat objectives for sale but don't be tempted. They are incompatible for your scope.

GOLGO13
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Re: Older B&L microscope question

#5 Post by GOLGO13 » Sun Jan 27, 2019 7:55 pm

How can I figure out what the correct eyepieces are? Can you direct me to an image or ebay posting? Thanks for your help. I paid $200 for it, so maybe a bit much but it is in good shape in general.

I'd be interested in the darkfield setup also.

Below is what this one is:

Image

apochronaut
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Re: Older B&L microscope question

#6 Post by apochronaut » Sun Jan 27, 2019 10:47 pm

Can you show a picture of the objectives?

GOLGO13
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Re: Older B&L microscope question

#7 Post by GOLGO13 » Sun Jan 27, 2019 11:27 pm

The low power one is not part of the same set. But the rest look like they were original. I took an extra photo of the B&L name to give you and idea of age.

Image
Image
Image
Image
Image

desertrat
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Re: Older B&L microscope question

#8 Post by desertrat » Sun Jan 27, 2019 11:36 pm

That 8mm 21X objective will be great for getting a closer look at tiny pond critters and algae after you've looked at them with the 10X. After I got a 20X objective for my AO 'scope, I seldom use the 43X on pond life slides. The 20x shows almost as fine detail as the 43X and has more depth of focus.
Rick

A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition

GOLGO13
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Re: Older B&L microscope question

#9 Post by GOLGO13 » Sun Jan 27, 2019 11:40 pm

one sort of not great thing is it has a 2x tele-extender inside. so everything is 2x normal

apochronaut
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Re: Older B&L microscope question

#10 Post by apochronaut » Mon Jan 28, 2019 3:10 pm

B & L literature is hard to find but there is some.
You have a 2X tube lens in there apparently, so I am unsure as to what effect it has on the overall corrections. One would assume none; just a magnification factor. The comments below are gleaned from actually testing eyepiece and objective combinations.

Your 4X is not a Rochester objective. It may be one of the imports that B & L got into in the 60s and if so it is most likely an early Olympus but pretty much the same as most basic Japanese objectives from the 60s. It most likely will need slightly different corrections off axis than the Rochester objectives but in the day, low power objectives mostly came with the expectation that there would be curvature of field and some peripheral ca. The B & L 3.5X .09 N.A. is a very nice low power objective for it's time and will have better peripheral imaging when using eyepieces suited to your other objectives than the one you have. The rest of your objectives are all of the 50's production in their 160mm range.

The eyepieces your microscope came with are for a stereo microscope.Generally speaking stereo microscope eyepieces are designed to correct for aberrations differently than diascopic or episcopic microscopes. You probably find that there is a fair amount of ca towards the periphery of the field. 10X eyepiece options for your microscope were :

Huygens, marked just 10X. These have a fairly limited f.o.v., short eye relief but they have fairly good corrections towards the periphery of the field.
Compens, marked 10x compens and later 10x compens red dot( i'm pretty sure these were strain free versions). These also have a fairly limited f.o.v. and eye relief but offer better edge correction than the Huygens, although the ca is of a reversed order , usually.
Hyperplane, marked 10x Hyperplane. These offer a flatter field than both of the above with some deficiency of corrections but the f.o.v. is still limited by todays standards.
10x W.F. The field is pretty wide with these but as the off axis angle increases, so does the ca.
All of the above had an eyelens housing that looked like the one in this ebay listing : https://www.ebay.com/itm/BAUSCH-LOMB-7- ... rk:16:pf:0

Later, in the 60's when the Dynoptics with the in base illuminator arrived along with the Dynazoom, they issued eyepieces with large extended sections up to the eyelens, similar to what you have. You will find 10x W.F. 23mm and 10X W.F. 22mm, if you go looking. The 23 and 22mm seem to be measures of eye relief, not fields or tube diameter.
In tests I have performed using all of the above eyepieces with B & L 160mm objectives, the 10x W.F. 22mm gave the best results when a combination of f.o.v. and freedom from peripheral ca are considered. In fact, the f.o.v. is close to 20mm and quite flat and chroma free. Using those eyepieces will get your microscope performing like a much more modern instrument, with a sharp wide distortion free field.
Here is an array of various ones; 22mm on the left, 23mm to it's right being sold surplus.
https://www.ebay.com/itm/LOT-6-EA-BAUSC ... SwkNZUhoSL



The down side to all this is that the 22mm eyepieces are not common. The 23mm ones are fairly common but they are easily outperformed by the ones marked 22mm. My guess is that the 23mm ones were originally for a stereo microscope. So, far I can find no literature to confirm this but they offer no advantage to an older B & L diascopic microscope, whereas those marked 22mm definitely do. There is a pair on ebay right now but they are pretty pricey. Cheaper ones will come along.

The 2X teleconverter is a bit of a problem but you can get around that. Basically, your objectives are now working at double their magnification, so getting down to a 3.5X .09 objective and then replacing the 43X .65 with a Bausch & Lomb 40X 1.0 oil fluorite will give you 75X, 200X, 420X, and 800X oil immersion. None of your objectives would be overshooting their N.A. and empty magnification wouldn't be an issue. You can't really use that 43X .65 with a 2x bump in magnification.
Those 40X 1.0 oil fluorite objectives are fairly common. There is one on ebay right now but they want too much for it. I have a nice one if you are interested.
Last edited by apochronaut on Mon Jan 28, 2019 3:44 pm, edited 1 time in total.

GOLGO13
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Re: Older B&L microscope question

#11 Post by GOLGO13 » Mon Jan 28, 2019 3:22 pm

Thanks for the information. Very helpful. I did notice the 43x objective seems a bit not useful. I'll look for a 3.5. I did see some of the 22mm wf for cheap but looked a bit damaged. And the expensive ones also.

The 2x is a bit of a shame, but I have a stereo scope that gives 10x and 30x. So I'll use both together.

desertrat
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Re: Older B&L microscope question

#12 Post by desertrat » Mon Jan 28, 2019 4:09 pm

I have one of the older B&L binocular models from the late '40s or early '50s, the one with the big, bulging, one piece binocular head and body combination. I'm guessing from the height of the eyepiece tubes above the objective turret that it has some kind of correcting lens above the turret to work with 160mm objectives. Any chance this lens could be used as a 1X correcting lens in the dynoptic above?
Rick

A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition

apochronaut
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Re: Older B&L microscope question

#13 Post by apochronaut » Mon Jan 28, 2019 7:28 pm

That might take some measuring and testing in order to confirm but it sounds likely enough. It's possible the telan lens is unique to each head, though.

Another scenario I could see for this scope, which would take advantage of the 2X head, would be to fit it out with a divisible 10X, which splits to become a 4X( the 4 isn't that great but it is an acceptable scanning lens) and then a good 10X .25 when back together, plus a B & L 20X .65 apochromat, a B & L 47.5X .95 dry apochromat and a 61X 1.4 N.A. oil immersion apochromat. With 10X compens eyepieces there would be 80X, 200x, 400X, 900x( dry) and 1220X oil immersion; all well within the boundaries of the objective's N.A's. If one didn't really need the 80X, then a 10X .30 apochromat would be best. They did not make a divisible apochromat.
The compens eyepieces would impose some degree of field of view limitation but one can learn to work with that. When I am using an older apochromat microscope with a 12mm f.o.v. I don't really notice the limitation because the quality of the image is so good.

MicroBob
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Re: Older B&L microscope question

#14 Post by MicroBob » Tue Jan 29, 2019 7:58 am

Congratulations to you nice new microscope! It is a fine combination of old manufacturing effort and modern ergonomics.

The cables coming out of the lamp tube in the first picture don't look original. Is the lamp holder and original lamp in there?

@Apochronaut: Old binocular tubes often had a tube factor above 1,0, in some horse shoe models reaching 2,0. This was not a feature but caused by design constraints. Do you know what the standard tube factor for this model was?

Bob

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Re: Older B&L microscope question

#15 Post by apochronaut » Tue Jan 29, 2019 2:18 pm

It was 1X. The magnification factor in the head was an option. This was a transition scope for B & L. Microscope development was pretty stagnant through the 40's for obvious reasons. This stand, kind of held the fort while they worked out the design of their 1950's forte, the integrated illuminator Dynoptic and the Dynazoom, which later received a well thought out complement of modified infinity corrected optics of outstanding performance . In that last incarnation of the Dynoptic, B & L opted to produce 125X 1.25 and 125X 1.4 objectives, then with the Dynazoom the head had a variable zoom from 1-2X.
12.5X eyepieces slowly lost favour as W.F. 10X designs came into their own.
This early 50's Dynoptic, with it's low fine focus was intended to compete head to head with the venerable heavy cast brass Spencer # 5, which had come on the market in the early 30's. The Spencer was a wholly superior instrument but the Dynoptic could be produced and sold much cheaper, due to it's aluminum construction. The complement of objectives was virtually identical between the two. You see considerably more B & L 3mm( 61X) 1.4 N.A. apochromats around than Spencers, so the 2X heads with photo port probably were put to good use in some research labs. The Spencer 3mm 1.4 N.A. objectives, if used to their fullest potential, would need 20X eyepieces. I don't think they were doing heads with a greater than 1x mag. factor at Spencer by the 50's. At Spencer years ago though, they did. When they sold a microscope with a magnification factor in the head, the objectives would be marked with the multiplied magnification factored in. You can find 16mm 12X .25, 4mm 62X .85 and 1.8mm 140X 1.30 objectives and likely others. They look and perform exactly like the same focal length objectives with normal 160mm magnifications stamped on them.
Last edited by apochronaut on Tue Jan 29, 2019 2:37 pm, edited 1 time in total.

MicroBob
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Re: Older B&L microscope question

#16 Post by MicroBob » Tue Jan 29, 2019 2:35 pm

Hi Phil,
thank you for the detailed explanation! I don't have a wide overview over the development of binocular tube factors from german makers, but here a few:

Zeiss Jena LG and Lumipan from mid- to end 30s on: 1,5x
Zeiss Jena NG and NF from ca. early 60s on: 1,0x

Zeiss West Standard from late 40s on: 1,0x
Zeiss West Standard Siedentopf bino around 1970 for some years: 1,25x

Lomo Biolam: 1,6x

A tube factor of 1 was sold as a very attractive novelty, so B&L was very advanced at this point of time.

Bob

GOLGO13
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Re: Older B&L microscope question

#17 Post by GOLGO13 » Tue Jan 29, 2019 2:48 pm

The lamp itself is an improvised setup. The mirror is in there though. It has a 15 watt halogen bulb in it. You can adjust brightness by pulling it in and out.

apochronaut
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Re: Older B&L microscope question

#18 Post by apochronaut » Tue Jan 29, 2019 5:13 pm

It wasn't really innovative at all, it was totally standard and normal for both Spencer and Bausch & Lomb stands to have a 1X factor in the heads, going back as far as binocular heads were introduced by them. I have only come a across a few that weren't. Of the hundreds of Spencer objectives I have looked at, only 4 of those have been marked with a factored magnification. That is not a practice that I know of B & L using.
In Spencer's 1917 catalogue, the first one I have access to that details a binocular head, I can find no mention of any option of a multiplied magnification factor, nor in the 1924 catalogue. I'm pretty sure I have seen a factored head though but it was some time ago and my memory is hazy about it. Spencer did make a diocular, which could replace the monocular by threading into the upper portion of the monocular tube. This increased the tube length by a sufficient factor that the recommendation was to use 6X eyepieces in order to obtain the same magnification as with 10X eyepieces. There is a good chance that the factored objectives I have come across provided their stamped magnification, if 10X eyepieces were retained when using a diocular.

At any rate, few plus 1X heads came from Spencer and possibly only a few more from B & L. The preference with both companies seems to have been to offer an array of eyepiece magnifications and types and to have objectives available with sufficiently high N.A.s to accommodate them. B & L made a dramatic shift to a zoom magnification changer with the Dynazoom.

GOLGO13
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Re: Older B&L microscope question

#19 Post by GOLGO13 » Thu Jan 31, 2019 12:45 am

I picked up some normal 15x eyepieces (the normal ones) and they do seem to do a better job. I have 10x ones on the way also.

Only issue is there is pretty long eye relief, so keeping the image steady is a little tricky. Are there good eyecups for these normal eyepieces that can be bought?

apochronaut
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Re: Older B&L microscope question

#20 Post by apochronaut » Thu Jan 31, 2019 1:29 am

If you are saying you bought a pair of the 15X huygens eyepieces that would have been the normal ones for the achromats you have, then they would have that somewhat odd convex shape to the eyelens section, correct? I believe it originally was black lacquered brass but the later ones were bakelite. There were eyecups for those. They were close fitting and quite shallow...could be folded back over the eyepiece or unfurled to make up an eyecup. I'm pretty sure they were mostly gum rubber. I came across one once that had the consistency of tar. Their physical integrity is dependent on them being isolated from various solvent vapours. You might find some well stored ones around but they are definitely fairly rare.
I have a lot of eyecups ...will see if any thing I have works on those.

GOLGO13
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Re: Older B&L microscope question

#21 Post by GOLGO13 » Thu Jan 31, 2019 1:44 am

These are 15x wf. I got them pretty cheap...but unfortunately one of them has a tiny scratch in the middle. At low power it's fine, but at high power it's pretty obvious.

I find these are quite immersive. They remind me of a telescope eyepiece called the 28mm RKE which has a similar design and a ton of eye relief. That eyepiece appears to make the telescope eyepiece holder disappear...like looking through a porthole into space. These perform in a similar manner with the binocular vision.

Hopefully the 10x ones I ordered are in better shape. I am good at cleaning eyepieces, but nothing you can do with scratches.

EDIT: They are still quite usable. But just a few defects in the image. I messaged the seller and we'll see. I think they had many of these so maybe he'll send out another.

apochronaut
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Re: Older B&L microscope question

#22 Post by apochronaut » Thu Jan 31, 2019 10:57 am

To put it into more of a telescope terminology. You have a 2X barlow in the system already, so you are now effectively using 30X eyepieces. That is the equivalent of using a single digit focal length eyepiece in a telescope.
You are going way over the N.A. of all of your objectives and every one is in empty magnification.

Search N.A. and choose any one of the tutorials available. It should help explain why your imaging, despite whether it has a wide field or not will be poor.

Yes, I have an RKE 28mm. It is in a modified 4 1/4" reflector with an image erector, for terrestrial use. My daughter used to watch the ships going to and fro with it. Very nice eyepiece with a wide field but in your microscope , you are now using the equivalent of about a 15mm eyepiece with a 2X barlow.

GOLGO13
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Re: Older B&L microscope question

#23 Post by GOLGO13 » Thu Jan 31, 2019 7:41 pm

I am having a hard time understanding the N.A thing. With telescopes it's all about exit pupil and atmospheric conditions. Assuming perfect conditions you can push the power quite high without breakdown in image. And of course aperture plays a factor.

I have 10x wf arriving today, so hopefully that works out.

I don't see any wide field 5x eyepieces. Maybe because of design limitations.

It would be interesting if some of the hyper wide eyepiece innovations in telescopes could be applied in microscopy. Maybe the objectives are more the limitation?

desertrat
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Re: Older B&L microscope question

#24 Post by desertrat » Thu Jan 31, 2019 8:18 pm

There are three pairs of 6X Spencer eyepieces up on Ebay right now. I think they were used with a binocular adapter that mounted in old monocular microscope tubes? I wonder if they would give decent service in the B&L microscope with the 2X tube correcting lens? Some of the material at Neeley's website indicates the older AO/Spencer and B&L eyepieces are fairly compatible with each other.
Rick

A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition

apochronaut
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Re: Older B&L microscope question

#25 Post by apochronaut » Thu Jan 31, 2019 8:32 pm

That's possibly an idea. He would then be working with 12X, so even the 43X .65 would be under the critical limit. However, they are Huygens, so they would still leave an uncorrected periphery and although not as narrow a field as 5X, they are still fairly narrow.
Probably a better option would be to hold out for a set of B & L Hyperplane 7.5X, which would then be multiplied into 15X by the head; still under the threshold. You see them around occasionally. The field would be wider and the edges cleaner with the hyperplanes.

GOLGO13
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Re: Older B&L microscope question

#26 Post by GOLGO13 » Fri Feb 01, 2019 1:32 am

These are the new eyepieces. The 10x isn't as nice a wide field, but it's obviously a better fit magnification wise. Still, the 15x seems to work also.

The original 10x stereo eyepieces were not giving proper magnification. They were closer to the 15x ones.

I'll probably keep an eye open for others. I see some similar 5x and such online. They don't look like they are very wide, but could be worth having for lower magnification.

Image
Image

MicroBob
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Re: Older B&L microscope question

#27 Post by MicroBob » Fri Feb 01, 2019 7:31 am

RMS eyepiece tubes have 23mm diameter so the maximum field size is about 20mm. This can be fully used with a 10x eyepiece, so a 6x 20mm eyepiece shows the same 20mm field with less magnification so the image just looks smaller and covers a smaller angle of view.

If I were to equip this nice microscope for regular use I would try to find relatively modern eyepieces that fit to the optics.
This is a finity optics microscope so I would expect it to need correction eyepieces at least for the stronger objectives. The manufacturers used different amouts of colour correction in the eyepieces. The optical design always includes the point where the eyepieces pick up the image in the tube. For this I know values between 5 and 18mm but I have no idea what value would be right for 160mm B&L. Having this right ensures to keep good parfocality and optimum image quality. Phil, do you know about the colour correction and eyepiece pickup point for this microscope?
Then I would try to find suitable eyepieces from e.g. the 1980s, 6x to 10x magnification, 18-20mm field.

One way to make eyecups is to put bicycle inner tube over the eyepiece and fold it back onto itself.

Bob

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Re: Older B&L microscope question

#28 Post by apochronaut » Fri Feb 01, 2019 2:14 pm

GOLGO13 wrote:These are the new eyepieces. The 10x isn't as nice a wide field, but it's obviously a better fit magnification wise. Still, the 15x seems to work also.

The original 10x stereo eyepieces were not giving proper magnification. They were closer to the 15x ones.

I'll probably keep an eye open for others. I see some similar 5x and such online. They don't look like they are very wide, but could be worth having for lower magnification.

Image
Image

I think you are missing the point about the importance of peripheral correction to the overall image quality and as well the point about the importance of keeping within the N.A. of the objectives. W.F. is great but if it carries with it several layers of optical distortion, then it's real value is seriously compromised isn't it?

This is a common occurrence with people jumping from telescopes to microscopes. With a telescope, the objective is fixed, so there is a lot of talk and speculation about which eyepiece is best and so forth because that is the only method by which you can change magnification, f.o.v. or freedom from distortion of the image. With microscopes you don't just start buying different eyepieces . Of course you can put any eyepiece you want into the microscope as long as it fits and obtain up to the maximum possible field of view but only certain eyepieces are critically corrected to the optical parameters of the objectives being used. If you want to improve the resolution, f.o.v. or freedom from distortion of the image , it can only be done by altering the characteristics of the image within the light bundle emanating from the objective lens, then when those optical parameters have been maximized, you find an eyepiece match that complements the objective and most objective families, especially those from the past have specific needs.
The W.F. eyepieces you have bought were in fact made for your instrument but as previously mentioned in the 10th post in this thread, that wider field is not particularly well corrected. They were made at a time when the f.o.v. was a just emerging tool in microscopy; for histology primarily and it was very difficult to compensate for a non-plan objective design and produce a flat well corrected periphery that wide with the glass that was available at the time, or at least without huge cost. The later generation of those marked 22mm, produces as wide a field but with an almost fully corrected periphery with those objectives. As Bob points out, it is likely that a more modern eyepiece would produce as wide a field with better edge corrections but that would require experimentation in order to determine that because eyepieces are all over the place in the way they are corrected. Utilizing the known combination with the B & L 22mm 10X W.F. eyepieces is a safe bet for an excellent image.
The second problem you are encountering with the 15X eyepieces is empty magnification. In fact you do not have 10X and 15X eyepieces. You have 20X and 30X eyepieces because of the magnifier in the head. The maximum eyepiece magnification that you can use in that instrument with the 4X objective without entering the area of useless and often degrading empty magnification is 25X; for the 10X objective it is 25X; for the 20X objective it is 25X and for the 43X objective it is 15X, or 7.5X eyepieces x 2. Instead of buying into 15X W.F. eyepieces that give an awe inspiring but distorted W.F., full of empty magnification , your money would have been better spent replacing the pedestrian 43X .65 achromat you have with a B & L 45X .85 achromat, which would then be able to utilize 18.9X eyepieces, so close enough that your 10X x 2X eyepiece combination would probably work o.k. or as previously mentioned the B & L 40X 1.0 oil fluorite, which would easily handle 25X eyepieces, as well, so the 15X W.F.are out of the question anyway but at least you could use the 10X throughout your objective range without empty magnification. Another option open, in order to fully utilize the 2X magnifier in the head would be to find a set of B & L 12.5X eyepieces. I think they also made those in a W.F. version in the time but the peripheral corrections would be about the same as the 10X and 15X you already have.

GOLGO13
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Re: Older B&L microscope question

#29 Post by GOLGO13 » Fri Feb 01, 2019 6:29 pm

I am learning a bit, but it's a bit much to understand so far. But I am happy I have reasonable eyepieces in the 10x I got. They don't have much eye relief so no need for an eye cup. The nicer 10x 22mm are not available yet at a decent price. I've probably spent enough now as it is. But I have a few items I can list on ebay.

I did get the 3.5mm objective now. But still have to consider the possible replacement for the 43x.

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

Re: Older B&L microscope question

#30 Post by MicroBob » Fri Feb 01, 2019 7:48 pm

Don't worry, microscope technique is a wide and difficult field, but you don't have to be an expert to start working with the microscope.

Your lamp base probably had a lamp socket when new, that places the filament in the right spot. They tend to get lost when power supply and microscope are separated. For perfect function this is necessary, but as long as you get a fairly good image I would worry later. These bulbs run quite hot, so make sure it doesn't fall out while switched on.

Do you already have a topic in sight that you want to study?

Bob

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