Watch out: Olympus objectives with confusing names

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Macro_Cosmos
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Watch out: Olympus objectives with confusing names

Post by Macro_Cosmos »

Hi,
I recently was inclined to purchase one of those cheap "LCPlanApo 20x" objectives. This objective is missing a compensation cap, and offered for a very cheap price, around $100.
Someone I know online purchased one and the image quality was very bad, chromatic aberration performance was good since it is an apochromat.

Usually, LCPlan would imply a Live Culture Plan objective, typically these are used for inverted microscopes.
However, the LCPlanApo is actually an LCD Plan objective.
Olympus decided it was a good idea to not differentiate the two.

Both LC Plan objectives and LCD Plan objectives use the same letters LC!! #-o
It appears that the LCPlanApo cannot give a decent image without the compensation cap. Part CAP-G0.7 (G=glass, there are also P=plastic ones, and different thicknesses, other than 0.7)
This is especially (stupid) confusing, since one of them is a fluorite. The newer UIS2 line of objectives makes a distinction with an LCD designation.

Checking the documents Olympus no doubt does not want me to have...
List of LCD Plan Objectives, not suitable for use without the compensation cap. There are only 3 to look out for.
- LCPlanApo 20x: LCPLAP020X;LCD PL APO 20X OBJ, NA 0.40, WD 8.80MM, 0,.7, 1.1
- LCPlanApo 50x: LCPLAP050X;LCD PL APO 50X OBJ, NA 0.60, WD 3.10MM, 0,.7,1.1
- LCPlanFl 100x: LCPLFL100X;LCD PL FL 100X OBJ, NA 0.80, WD 1.10MM, 0.6~1.2

Anyhow, just a heads up.

Scarodactyl
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Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

That's interesting, as I just bought one as well (there are a bunch on eBay right now). From reading about them it seemed like without a cap they would need 3mm of glass between them and the subject, so it would definitely give a terrible image even with a normal cover glass.
I figure I can experiment with caps made from surplus shed windows of different thicknesses.

Scarodactyl
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Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

I got mine in. Unfortunately power flickering seems to have killed the halogen in my coaxial illuminator so no good pics, but its performance on wafer with a relatively thick piece of glass (from a gem box) oiled on was much better than without. I think it's just that it corrects for 3mm by default which is enormous.

viktor j nilsson
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Re: Watch out: Olympus objectives with confusing names

Post by viktor j nilsson »

Could still be useful to you when photographing inclusions, I reckon?

Scarodactyl
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Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

Thanks, I sure hope so. It is definitely more challenging to use but I'm hopeful it will come through. If I make a 3d printed design for caps I'll post it here.

Scarodactyl
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Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

OK, I had a brainwave on this. Cover caps are expensive and only available in a limited range of thicknesses, but even if I had a full set they'd be awful to use as I want to. The thread on the caps is m21x0.5mm and it's like 3mm deep, which means it'd be a long and slow process to swap caps. I never know ahead of time how far down an inclusion might be so that'd be a nightmare. What I wanted was a quick release mechanism, and I realized I design and 3d print that really easily. Behold!
Image
Image
I happened to have a 2mm coated glass window on hand so I figured I'd start with that. thanks to the tiny neodymium magnets it's holds the cap firmly but is easy to remove by rotating it out of alignment and pulling sideways (or just pulling downwards of course but that could disturb the subject.)
So, is there actually any point to this? Is it useful?
I think so. Here are two tests, one of inclusions in a faceted kyanite and the other very close crops of iron oxide inclusions in an opal, using the lcplanapo with an without the magnetic cap and compared against my mitutoyo 20x. They've been sharpened and contrast adjusted though admittedly fairly quickly and without an insane amount of care.
Image
The difference is very obvious in the kyanite--I spent a while looking for an inclusion at a depth that would be good with the cap attached (it isn't the exact ideal depth but it's not too far off) and then took shots with the cap off and with the mitutoyo.
Image
These tiny iron oxide inclusions are very challenging to shoot. There's some inherent softness since they're within opal which is...opalescent, as you'd guess, a bit milky. Somehow it seems to introduce a lot more spherical aberration in the mitutoyos than I'd expect--I'm not sure why as opal has a low RI, maybe they're just deeper than they look at first glance [edit: I measured the depth using an ad hoc depth gauge I got years back and forgot I had--about 0.03 inches or 0.73mm of opal which has about the same RI as coverslip glass, so it all tracks). Previously I've just lived with very suboptimal results on this type of inclusion, but with this I think I'll be able to aspire to merely somewhat suboptimal results. One nice thing was that the mitutoyo and uncapped photos had to be completely redone in touchups in helicon since the contrast was too low to pick the best frames, while the one with the cap only needed a bit of touchup.
Conclusion: it definitely makes a difference! As others have noted it gets a lot more finnickey as you get deeper into medium, and the range of depths giving ideal performance is surprisingly tight. In addition within gems even minor out of focus features between the subject and camera really add up if you're trying to look 3mm deep in a stone. This isn't going to be an all purpose type of objective, more of a pinch hitter, but I am certain it will let me take shots that I could not take otherwise. I imagine with a 3mm cover glass attached it would give performance similar to a mitutoyo on aps-c, albeit with much less working distance and more hassle. Now I just need to look for deals on nice little windows in other thicknesses.


One other note, I don't think LC stands for LCD or for Live Culture. I believe the L is for long working distance the the C indicates it is corrected for a thick cover glass, hence why the same label is used for LCplanfl and LCplanapos.

Macro_Cosmos
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Re: Watch out: Olympus objectives with confusing names

Post by Macro_Cosmos »

That is a really nice test, thanks! Yeah, considering the price it is offered from my side, it is a good deal. Great to know that optical flats keep fixing our woes regarding these whack industrial dumps.

I am not so sure about LC now, I thought it meant "Long c plan", but then a friend says it means "live culture" which makes sense since there are caps corrected for different thicknesses and materials (plastic vs. glass). :shock:
Either way, it is quite confusing.

Scarodactyl
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Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

The way it is presented in the catalogue is as the LCPlanApo/LCPlamFl-LCD series, which would be redundant if the LC stood for LCD.
It gets better. Apparently there was a BH2 era equivalent just labeled 'RK 20'.
Image
Huh. Really Kool? Like most industrial scopes from the 90s no documentation is easily available.
Bet that suite of caps would fit the lcplanapo.

shyamrathod
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Re: Watch out: Olympus objectives with confusing names

Post by shyamrathod »

Dear fellow members I was reading this discussion as I had bought 20x LC Planapo olympus without front cap were can I buy new cap is not a option so going foy DIY my application is photomicrography of crystals whats the distance between cover cap flat glass and lens any more details on were to get the flat corrector glass and of what mm thick

Scarodactyl
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Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

You need a 3mm thick window, there are some from China on eBay for like 20usd. You can 3d print a cap, it can go very close to the front lens, precise distance isnt important.

shyamrathod
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Re: Watch out: Olympus objectives with confusing names

Post by shyamrathod »

can anyone share 3d printer file for cap made
bought 3mm thick window from edmund sci
and the 20x apo lense without cover
shyamrathod@gmail.com

Scarodactyl
Posts: 1616
Joined: Sat Apr 14, 2018 10:26 am

Re: Watch out: Olympus objectives with confusing names

Post by Scarodactyl »

You'd need to make a custom one to fit your particular window. It shouldn't be difficult though, I did post the thread spec above.

shyamrathod
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Re: Watch out: Olympus objectives with confusing names

Post by shyamrathod »

Thank you so much .

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