LOMO compensating optics

[Crater Eddie]

I had been toying with the idea of using the LOMO long barrel PLAN APO objectives on my latest LOMO scope, but it has been pointed out to me that they require the compensating eyepieces to deliver full performance. I thought I had a set of LOMO compensating eyepieces, but all I can find in my cabinets are the standard and wide field eyepieces (NOT marked with the "K") that are used with the shorty objectives. So what kind of images can one expect with a mismatch like this? Horrible, or just not stellar?
I have read that the Olympus eyepiece correction is very near the LOMO correction, but I don't remember where I read that and Professer Google can't seem to find it. I have my eye on an objective, and I have an extra pair of Oly eyepieces, I'll likely give that a try while searching for the correcting eyepieces. But I thought I would ask opinions here.
CE

[zzffnn]

CE,

Plan apos will always outperform plan achromats, even with mismatch eyepieces. So the worse you can have is "not so stellar".

I did NOT know Olympus eyepieces (EPs) can provide similar compensation as LOMO K EPs.

I did hear from a highly experienced German microscopist, that Zeiss Kpl eyepieces are similar to LOMOs in terms of CA and SA. Their parfocal points (down eye tube) differ by 1mm (Zeiss Kpl residing 2.5 mm higher), IIRC. So you may use Zeiss Kpl as it is, or shave off its seating surface by 2.5 mm.

[zzffnn]

Sorry, the difference is 2.5mm (not 1mm), with LOMOs being lower. You can lift up LOMO EPs for Zeiss West DIN objectives, but Zeiss Kpl s ideally need to be shave off 2.5mm. In reality, 2.5mm is not a lot of error and you can just leave it.

I have edited my previous post.

[Crater Eddie]

I did NOT know Olympus eyepieces (EPs) can provide similar compensation as LOMO K EPs.

Don't take that as gospel, it's just something I read somewhere. And since I can't find it again I don't put too much faith in it, but am willing to test it. Thanks for the info on the Zeiss, I'll keep that in mind.
CE

[Micro-Bob]

The old Lomo stuff like the Biolam was a close copy of the Zeiss Jena stuff from 1945. The russians actually removed the whole Zeiss works from Jena and continued to produce on the old machines. For the old infinity Zeiss Jena microscopes the PK eyepieces were the plan compensating ones. Chromatic compensation is about the same as Zeiss West like the mentioned KPL. For newer Lomo plan apochromats I can't tell. My first try would be the CZJ PKs. When you get a nice image and good parfocality the eyepieces fit.

[zzffnn]

I did NOT know Olympus eyepieces (EPs) can provide similar compensation as LOMO K EPs.

Don't take that as gospel, it's just something I read somewhere. And since I can't find it again I don't put too much faith in it, but am willing to test it. Thanks for the info on the Zeiss, I'll keep that in mind.
CE

CE,

I saw a post that echoes what you mentioned. Here it is (see Pau's post that mentioned Olympus, Leitz and Zeiss): http://www.photomacrography.net/forum/v ... eiss+leitz

So Olympus and Zeiss may not be too different in terms of optical compensation. But long DIN and short versions may have different parfocal distance, thus tube length may be slightly different. Only a comparison can tell for sure, in reality.

[apochronaut]

Where there has been a very clear copy made of another mfg. existing designs, such as a lot of the early Lomo 160mm tube optics from pre-war Zeiss, one can make some not too risky assumptions, regarding cross manufacturer corrections. Outside of that, it is advisable to test in situ.
Clearly, the Japanese began their march into western markets, on the back of pilfered designs, that has been their stock in trade from the get go but as they gained market share with cheaper copies, made money, and could commit more capital to R&D, their designs became more creative and less derivative. Some earlier Japanese optics are straight copies.

I've got a whole box full of eyepieces, originally made for 160mm and 170mm tube systems and the corrections are all over the place. Even compensating eyepieces from competing manufacturers within an era, are not the same but to take a cursory look at the objective formulas for which they were tweaked, side by side, they seem very similar. Even huygens eyepieces are often not similar. Correction means correction and it is specific and quite refined. If you are getting even small amounts of uneven flare , astigmatism or chromatic aberration towards the periphery of the image, then the system is uncorrected. It's not o.k. for achromats to have expanding lateral c.a. as you look towards the periphery: more than apochromats, yes, but it should be relatively consistent across the field.
Some compensating eyepieces are plan compensating and these can be corrected, for primarily planarity, not overcorrected for spherical and chromatic aberration, as is the case with true compensating eyepieces.
By sometime into the 60's, the need for compensating eyepieces evaporated. The original problems associated with achieving corrections within an apochromatic objective were overcome by the access to improved low dispersion glass formulas, so from that point forward both achromats and apochromats could be corrected to the same levels but relative to the objective's innate potential and could use the same non-compensating eyepieces. Various manufacturers took this possibility up at differing times. My guess would be that the Russian designs meeting this criteria would have been later, rather than earlier, possibly even following Zeiss Jena patterns after the 80's.

[carlh6902]

American Science and Surplus used to have lomo compensating eyepieces for sale. I bet they still do. Seems like they were $20 each,

Carl

[Micro-Bob]

By sometime into the 60's, the need for compensating eyepieces evaporated. The original problems associated with achieving corrections within an apochromatic objective were overcome by the access to improved low dispersion glass formulas, so from that point forward both achromats and apochromats could be corrected to the same levels but relative to the objective's innate potential and could use the same non-compensating eyepieces. Various manufacturers took this possibility up at differing times. My guess would be that the Russian designs meeting this criteria would have been later, rather than earlier, possibly even following Zeiss Jena patterns after the 80's.

Correct me if I'm wrong but from my point of view these new possibilities were only used when new microscope systems were developed. Within for instance the Zeiss Standard system from the late 40th to the late 80th they stayed with the same always compatible system.

By the way: One new invention of the Standard was that the weaker objectives had chromatic abberation added in their calculation so they could be used with the same eyepieces as the stronger objectives and apochromats. Zeiss Jena had separate eyepieces until the CF 250 system around 1980.

[apochronaut]

That would seem likely because for most of the first hundred years of the great heyday of the microscope, they were largely system based, not module based, although there was some attempt by the R.M.S. to increase modularity. Clearly the companies resisted that attempt, preferring as much as possible to capture their customers into their system. It would be counter-productive to introduce an optical improvement to a system and for users to have to jump through hoops to use it efficiently, so most often, changes or improvements would take place in a new model, including a somewhat modified system to go with it. Sometimes, their would be reverse cross-compatability between model systems or between manufacturers but that wasn't the rule.

Increasingly, manufacturers have been introducing modular systems, where there is no specific functional interdependence of components in the system, largely being replaced by a physical dependence. I'm sure a lot of what is going on has been determined by accountants. Some modularity going forward does take place, for instance with AO, despite the fact that there was a wholesale change in the degree of correction used in the tube lens for all of the AO and Reichert instruments using infinity corrected D.I.N. optics around 1985, one can retrofit earlier AO and Reichert short barrel infinity systems , to use some of the later improvements. It takes only a change in the tube lens, usually by virtue of mounting a series 400 Seidentopf head.
AO themselves, did this. The objectives made for all of the inverted microscope models were all the same short barrel series. When the last model, the 1820 came out and consistent with the 400 series designs, they were fitted with a black version of the older series 100 head, not the Seidentopf head of the series 400. This was necessary because the objectives available needed the earlier degree of correction. They never made updated L.W.D. objectives for the 1820. Oddly, some AO literature shows the series 400 head and I have seen such a set tup on ebay. If such an arrangement exists and is fully functional, AO must have made some series 400 heads, with the earlier tube lens mounted into them( they are the same diameter), specifically for the 1820 stands.

[Crater Eddie]

Lots of great information here!

American Science and Surplus used to have lomo compensating eyepieces for sale. I bet they still do. Seems like they were $20 each,

Carl

Carl, AS&S hasn't had the EKW-10X eyepieces for quite a while, I ask them every now and then to check stock for a pair. It has a been a while since I asked, might as well give it another try. Thanks for the reminder.
CE

[Crater Eddie]

I just couldn't shake the feeling that I should have a pair of the LOMO K-10X/18 compensating eyepieces somewhere, its been bugging me for quite a while. But after nearly turning the lab inside out a couple of times I proved to myself beyond a shadow of a doubt that I don't have them. Then last night it finally dawned on me. So I messaged the friends to whom I donated a spare BIOLAM a couple of years ago, and sure enough that's where they are. About 10 miles down the road.
CE

[zzffnn]

Good news, CE!

Do the eyepieces say "K10x/18" on them? Those are not commonly seen on Biolams. But you may be just lucky.

[Crater Eddie]

Yes, K10x/18, I had him read me all the print on the eyepieces. I'm pretty sure they didn't come on the BIOLAM, I think they came on my L-2-2. It had a binocular head on it when I got it, the spare (used) Biolam came with the trinoc. I put the trinoc on the L-2-2, and a spare binoc on the BIOLAM (keeping the binoc that came on the L-2-2). Somewhere in swapping things around the K's got put on the donated BIOLAM and I never noticed.
CE

[apochronaut]

It seems that Lomo changed the corrections in their optics between the early series that had Zeiss mediated corrections and the EA series, which pre-dated the D.I.N. optics. It is possible that the corrections were further changed for the D.I.N. objectives too, since differing eyepiece model #'s show up for some earlier objectives and the D.I.N. series.

Although I do not have any Lomo eyepieces, I have several Lomo objectives; an EAF 30X .90 w.i., achromat, a 40x .75 w.i. achromat and a 70x 1.23 w.i. apochromat. The latter two are from the period when the bulk of the optics were derived from pre-war Zeiss designs. The EA series may be of in house design.
Despite, not having any Lomo eyepieces, I do have some pre-war Zeiss eyepieces and a considerable array of eyepieces from various mfg., with which to test compatibility.
The EAF 30x achromat objective is very malcorrected with all of the non-compensating eyepieces I tried it with. Odd, because it is an achromat. One bad example is a C.B.S.( Conrad Beck and Son) 10X PL, through which it displays severe overcorrection, beginning just off axis and progressing to severe at the periphery. Working with this objective under normal circumstances would lead one to believe that it just has a high level of lateral CA. With any compensating eyepiece,however, it achieves varying degrees of compensation. With a set of Reichert PK 10x eyepieces, originally used in the Zetopan/Neopan etc. 160mm system, it achieves almost perfect freedom from CA and as well almost perfect field flattening. It also works well with Olympus Bi 10XWF, Olympus WK10X/20L, Carl Zeiss KPL 12.5X and Vickers 10X compensating, although the degree of field flattening and perfection of correction is slightly less at the extreme periphery of the field with some of those. This is partly due, to pushing the f.o.v. to 20mm with some of them, whereas the Reichert PK 10X are about 17mm, so they vignette that extra 1.5mm of the periphery.
With eyepieces that show no sign of being in the compensating class, the CA is too severe to be acceptable. It just makes it seem like a bad objective, whereas in fact , when well corrected it performs like a fluorite, which it must be, given it's extreme .90 N.A.
Trialling the same group of eyepieces with the older 40x .70 w.i. achromat, pretty much the situation is reversed. The Reichert PK 10X display moderate overcorrection , the Vickers, less so , the Olympus Bi 10X WF ; severe overcorrection, yet a wider field 1950's Watson, 10X Huygens was nearly perfect, displaying some field flattening and excellent edge to edge correction. It also, seemed to increase the contrast.
So, the EA achromats seem to be "tuned" similarly to an older apochromat....requiring under correction for CA at the eyepiece. Since Lomo still offers both non-compensating and compensating eyepieces, it would seem possible that their newer compensating eyepieces might be different from the older ones and not be cross compatible.

[zzffnn]

apo,

Have you tried your LOMO 70/1.23 WI apo with the same batch of eyepieces (and does it behave like the EAF 30/0.9 WI)?

I saw CA, when I used that EAF 30/0.9 WI with LOMO K10/18 eyepieces (which may be a newer version of LOMO compensating eyepiece). That was what I used to record the video that I showed you, though the oblique filter that I used may add CA and reduce planarity. I did not use that EAF 30/0.9 much, so I cannot say for sure.

I did use older LOMO apos quite a bit, including the 70/1.23 WI apo, with LOMO K10/18 eyepieces. I remember CA correction and central resolution is great, though field flatness and contrast was never great to start with (those apos are of very old designs).

[apochronaut]

The 70x 1.23 apochromat has a different need than either the 30x .90 achromat or the 40x .75 achromat. Presumably, Lomo K eyepieces from the period of their mfg. are well corrected for it, plus older Zeiss Komp. eyepieces. It works well, with some of the compensating eyepieces I have here but I have not done an exhaustive trial. With the Reichert PK 10X for instance, it is under corrected, slightly.

[Crater Eddie]

So the newer EKW-10x (wide field) eyepieces might have different correction than the K10x/18 which I assume to be an older design.
Looking at the LOMO PLC site, which is still up for informational purposes, it implies that the ESW-10x (wide field) eyepieces, which I have, also provide some correction for CA, which might or might not be different from one or both of the others.
I guess when I get the K10x/18's back I need to do a comparison. And then try them all with one of the PlanApo objectives, if I ever get one.
CE

[apochronaut]

Unless there is a tube lens that you know has been designed to complete the needed corrections or you know that the objective in question has been designed to have full corrections, it can be assumed that any eyepiece provides further correction, however:
The degree is variable and in some cases, as is the case with the Lomo EA objective I tested, the requirement is inverse.

If an eyepiece has a blue border clinging to the field stop, then it is designed to over correct, if it has a yellow/orange border, then it is designed to under correct. Older apochromat objectives, which were designed to provide as complete correction for spherical aberration as possible, were left in a state of over correction with respect to CA, as a result. At first, this was caused by the materials not being available to do the job equivalently for both. Later, it became possible but the cost was astronomical and in many cases the objective barrels too small, in which to fit the required number of elements. In some older patents for highly corrected objectives, very large barrel lengths are theorized. Planarity also was becoming a necessary marketing factor and just to make a planachromat, sometimes requires 10 elements or more, let alone make it apochromatic too. This usually required a larger barrel, in order to accommodate so much glass. One by one manufacturers adopted D.I.N. or even larger barrels, as the requirement for more glass elements incorporated into designs,dictated.

Barrels need to be kept mechanically consistent, so even though smaller barrels could be used for an average achromat, large barrels were used in order to maintain consistency with objectives such as planapos, that need more glass and a larger barrel to hold it.

The degree of compensation that eyepieces had to have also changed , along with the morphing of objective correction. My guess would be that the adoption of D.I.N. objective barrels at Lomo, heralded a pretty big change in objective design and the levels of compensation they required.

To go to something I know a little better, as another way of painting the picture, if you look at the development of AO's optics, after w.w.II, you can see several leaps forward in terms of extending the objective length with tube lenses and then eventually a wholesale adoption of the D.I.N. format. Essentially, those tube lenses; first in the series 2/4 160mm system and then the early 34mm parfocal infinity system, functioned as back lenses for each objective, thus increasing the barrel length, effectively. In the 2/4 there was modest ca and planarity correction, and due to the use of existing objective designs, it was not possible for it to be consistently good for all objectives. With the series 10 , the tube lens took on a more consistently corrective nature. The early non plan 40x .80 apochromat they made for that infinity system had a back lens about 4mm from the rear of the objective and by the time the equivalent planapo came out around 1985, the lenses were just stuffed into the barrel. Their ultimate 40x advanced planachro( cat. # 1309), which has close to apo performance weighs 25gm.The 40x planapo weighs 32gm. In fact a Kowa made Japanese D.I.N. achromat also weighs 32gm and is 35% longer. That planapo has no room for any additional elements.

The cat. # 1029 100x 1.25 advanced planachro had so many elements that the rear element sticks out the back of the objective about 2mm. Clearly, they weren't going to be putting a 100x planapo into a 34mm parfocal barrel and in order to have objectives with more complete correction, they needed a D.I.N. barrel, which they adopted for the series 400. Probably a similar situation took place at Lomo.
B & L dealt with a similar issue but their ultimate solution was a little different.

[zzffnn]

If an eyepiece has a blue border clinging to the field stop, then it is designed to over correct, if it has a yellow/orange border, then it is designed to under correct.

Thank you, apo, for this info.

Then my LOMO K10x/18 eyepieces under-correct for sure. And if I remember correctly, same goes for Olympus short barrel WK10 and Nikon HKW10 eyepieces. In fact, I don't think I ever had/have an eyepiece with blue field edge.

[zzffnn]

Apo,

And what did you mean by under correct? Negative (reducing) correction?

And "over correct" means positive (adding) correction? Does Huygens' eyepiece provide positive correction? I think I do have the AO 6x Huygens you sold me, but I did not use them enough to remember their edge color.

[apochronaut]

My memory tells me that you wanted a set of lower power huygens eyepieces with a combination of decent f.o.v. and high eye relief, so you could wear glasses. I believe you bought one pair and then another, later, for some other application? so you must have liked them. I have no idea how you used them but I remember at the time that you said, chromatic aberration didn't bother you. Cat.# 147 W.F. 15X eyepieces are also slightly corrected for CA in the objective, which you have.

Almost all eyepieces are compensating, unless they are a very complex design that renders the incoming image unchanged, except for magnification.. Harnessing an eyepiece's defects, so that they counteract the defects of the light bundle arriving from the objective or tube lens is the art of compensation. Since apochromats have traditionally been deliberately over corrected for CA, as a way of controlling spherical aberration with the understanding that the over correction could be compensated for with under correction in the eyepiece, a convention arose labelling such eyepieces "compensating". Eyepieces such as Huygens, Ramsden, Kellner etc. are in fact compensating as well but do so in an entirely different fashion than those specified as compensating.

It has to do with what the objective requires, not whether over or under compensating is good or bad. Achromat objectives, are naturally under corrected, otherwise they wouldn't be achromats. As it turns out the huygens design is naturally over corrected in such a way as to mostly compensate for the natural defects of achromats. This can be tweaked more or less to create as close a balance as is possible but achromats are achromats and they can only be made as good as they are. Using compens eyepieces with them, under the belief that they will magically reduce the CA of the achromats, is not possible.

[zzffnn]

Thanks, apo. I asked as I was just curious.

I still have the 6x EPs and like them (could not find anything better for the money). Just have not gotten to use them a lot yet. I use them for reflected light macro, so CA is usually not an issue (not like transmitted oblique light).

[Crater Eddie]

I finally bit the bullet and now have a couple of Plan Apo objectives on their way from the Ukraine. Hopefully I'll have some observations to share in a few weeks.
CE

[charlie g]

Thank you all for this terrific thread, C.E.(OP), fann, phil, et all ! I have a collection of vintage 160mm stands which sadly have occulars on their binoc or trinoc, or monoc heads which I never listed in a notebook. It's easy to peek in my cigarbox of occulars and seek 'compensating' occulars, so I just did.

From all this threads discussion it really does seem as though one has to actually use the ocular/objective combos to sense optical performance...I get sense of being at a wine tasting to glean the performance remarks in this thread..very interesting for me.

I have no idea the production year of this ocular..but it's black metal top has etched+ white painted spec: "10Xcompen.". The darkmess on the silver barrel is a reflection optical effect on my dim room lighting..the barrel is pristine shinny silver metal. The other side of the black metal top has etched,,,but not painted: "B&L Optical...blahh blahh .

Let me know Crater Eddy, if you'd like to try this ocular with your LOMO Plan Apo objectives. Charlie Guevara, finger lakes/US

[charlie g]

I also found this in my cigar box of occulars ( again, sadly I never thought to write down lists of the occulars and objectives on my err family of vintage stands.).

Here is a black metal top..very long barrel " WILD 6XK " ocular. For quite a few years I had held little digital 'point and shoot' cameras at my workhorse stand using occulars like this one.

All this compensating ocular info really intimidates me...but a very interesting thread for me. You might try this one as well?

In e-Bay excitement years ago I purchased four LOMO plan apos because the price was so good. But they are all RMS 'short barrel' so I sadly can only use them on vintage stands...my workhorse Nikon Labophot does not 'rack down enough' for them.

[Crater Eddie]

Update:

The Plan Apo objectives went through US Customs yesterday, and were last scanned this afternoon at the "GARDEN CITY NY DISTRIBUTION CENTER". I think I'll likely have them by the end of next week or so.

Charley G, I would be delighted to try out your oculars if you would care to ship them down here. I promise to take good care of them and ship them back in good condition. Mighty kind of you to offer.

I still don't have my set of K-10x/18 oculars back, have obtained a New Old Stock set of WF10x/18's to swap them out with, just haven't gotten around to doing it yet. I talked to this fellow today, he has a wok and a cast iron skillet or two that need cleaning and re-seasoning, so we'll work out the trade while dealing with that.
CE

[charlie g]

Please clarify if you want to try both the Wild 6XK, and the B&L 10X Compens. I'll PM you now. Charlie guevara

[Crater Eddie]

IMG_1680.JPG (103.47 KiB) Viewed 11556 times

New Russian glass!
They arrived today, a little sooner than I expected. That was a pretty quick trip all the way from Ukraine!
They sure are hefty, have a nice heavy feel to them, and the glass looks clean through the inspection scope. I don't have my K-10x/18's yet, but tonight I'll try these out with the eyepieces that I do have and see how that goes.
Should I start a new thread for this or continue here?
CE

[apochronaut]

So, those are still 160mm optics? Interesting that they would tone down the 40x to .65, which is highly unusual for a 4mm apo. Likely it has a greater w.d., than the more common high N.A. apos, which would definitely make it more user friendly.

Only other similar effort I have come across is the infinity AO/Reichert planfluorite( which works like an apo) at 40x .70. It has a greater w.d. than the Reichert 25x .65 planapo.