Testing Olympus UPlanFL N 4x 0.13 (FN 26.5)

[Pau]

I found this lens used at a good price and being aware that Charles Krebs uses it with excellent results I bought it. It came pretty dirty and after a good cleaning I'm testing it. I find the results pretty good although my testing abilities and subjects are not the best.
Chromatic aberrations are present but I think they are small

I would like to see your opinions.

The Canon 70-200 f4 IS USM at f4 and 200mm was used as tube lens. Illumination with two Ikea Jansjo diffused with half ping pong ball around the subject. Canon 7D in LV. Stacked in Zerene PMax
1- Laser printed paper
Whole frame


100% crop near the center


100% crop corner


100% crop. Single shot near the center, subject angled to show LoCA, undiffused light


2- Polipodium sporangia
Whole frame


100% crop near the center


100% crop corner

[SebastianFg]

Hello,
I thought Olympus established a System based on 180mm tube lens.
That would improve your results probably.
Best regards,
Sebastian

[Pau]

You're right, Olympus microscopes have a 180mm tube lens but because I see some corner degradation I find better to use a slightly longer TL. Altering the FL only changes magnification, so (calculated, not yet actually measured) at 200mm I'm getting 4.4X
For subjects where the corners don't matter like a typical insect portrait I could use it down to 140mm providing 3.1X

The objective is designed (and marked) for 26.5mm FN and the Canon APSC image diagonal is 27.04mm so they seem to match very well, but extreme corners are not so good.

[Pau]

My conclusion: it's a very good objective, with very good resolution and only some degradation at extreme corners, low CA and very useful WD, not at the level of Mitutoyo but close,
.. and the good news: right now there are five of them at Ebay, I think they could be bought for modest prices as I did.

[WalterD]

That was an interesting comparison, Pau. Looking forward to see more pictures made through that objective.

Regards,

Walter

[Duke]

Hi, Pau and everyone!
I've got this objective and it performs well at the center, but very badly at the corners. There is excessive amount of coma and astigmatism...
Even worse than Nikon CF PLAN 5x 0.13, which has less geometric aberrations, but far worse LCA.
For whatever reasons, all infinite objectives of low power range (4-5x) (I've tested quite a few now - Olympus MPLANFLs, UPLANFLs , Nikon CF, CFI60) are the worst in terms of a corner performance, while others 10x-20x-50x perform nicely. I'd expect it to be other way around, since designing a low power objective would be much easier task, than higher. All of Nikon finite objectives I own (E Plan 4x 0.10, CFN Plan 4x 0.13, BD Plan 5x 0.10) producing much better image in the corners, than the others in the set. I wonder, what went wrong with the infinity ones...
Is this normal?
Setup is Nikon Eclipse-series erected image UW trinocular head, custom research grade microscope (no optics in light path besides the beamsplitter) LOMO LUMAM R8.
I'll post the image bit later.

[dmillard]

I found this lens used at a good price and being aware that Charles Krebs uses it with excellent results I bought it. It came pretty dirty and after a good cleaning I'm testing it. I find the results pretty good although my testing abilities and subjects are not the best.
Chromatic aberrations are present but I think they are small

I would like to see your opinions.

Hello Pau,

It looks pretty good to me.

I use several Olympus objectives on a UM-2 Measurescope, primarily with an Olympus trinocular head (also inspired by Charles Krebs). I occasionally use these objectives with other tube lenses, including an Olympus U-TLU.

I had always considered the coverage of these particular objectives to be good, expecting a potentially slight fall-off in the corners because the designated 26.5mm image circle is smaller than the 28mm diagonal of my sensor. However, I recently saw that Olympus offers two versions of their tube lenses , a super-wide field tube lense (SWTLU-C), advertised as having a full 26.5mm image circle, and a single port tube lens (U-TLU), which only gives 22mm.
https://www.edmundoptics.com/p/Olympus- ... gKfL_D_BwE
https://www.olympus-lifescience.com/en/ ... ts/swtlu-c

While I don't have the UPlanFLN 4x/0.13, I have a UPlanApo 4x/0.16, a UMPlanFL 10x/0.30, and an LMPlanFl 20x/0.40. I'll do a test of these this weekend to examine their coverage more critically, and report back.

Regards,
David

[Pau]

I've got this objective and it performs well at the center, but very badly at the corners. There is excessive amount of coma and astigmatism...
Even worse than Nikon CF PLAN 5x 0.13, which has less geometric aberrations, but far worse LCA.

Hi Duke,
What camera sensor size do you use?
Is the corner IQ worse than mine? (another possibility is that you are more exigent, of course) Once radial CA is corrected in RAW processing I find mine very good although not stellar. LoCA is small and eliminated by the stack process.

For whatever reasons, all infinite objectives of low power range (4-5x) (I've tested quite a few now - Olympus MPLANFLs, UPLANFLs , Nikon CF, CFI60) are the worst in terms of a corner performance, while others 10x-20x-50x perform nicely. I'd expect it to be other way around, since designing a low power objective would be much easier task, than higher. All of Nikon finite objectives I own (E Plan 4x 0.10, CFN Plan 4x 0.13, BD Plan 5x 0.10) producing much better image in the corners, than the others in the set. I wonder, what went wrong with the infinity ones...
Is this normal?

I can't answer, I only have one of these CF finite objectives, a Nikon MPlan 5/0.10 210/0 but I haven't seriously tested it as I only wanted it as scanning objective to be paired with my MPlan Apo 40/0.80

Robert OToole posted at his site https://www.closeuphotography.com/ several tests. In one of them a Nikon SFluor 5/0.20 shines at the corners, although it's a rare and expensive objective https://www.closeuphotography.com/4x-te ... objectives

Setup is Nikon Eclipse-series erected image UW trinocular head, custom research grade microscope (no optics in light path besides the beamsplitter) LOMO LUMAM R8.
I'll post the image bit later.

Will be nice to look at it.

[Pau]

...
While I don't have the UPlanFLN 4x/0.13, I have a UPlanApo 4x/0.16, a UMPlanFL 10x/0.30, and an LMPlanFl 20x/0.40. I'll do a test of these this weekend to examine their coverage more critically, and report back.

Hi David,

It would be very nice to see your tests (and in particular the LMPlanFl 20x/0.40 ones as I also have this objective )

I'm beginning to suspect that Olympus tube lenses do something more than just converging the light rays in a neutral way.
(In a maybe similar case, when I got a pair of Nikon CFW eyepieces I was very surprised to see that they are compensating (orange halo...) although in a much lower quantity than the Leitz and Zeiss I was used to. This could explain the small but present amount of radial CA present in CF finite objectives, even if Plan Apo)

[Lou Jost]

I thought Olympus established a System based on 180mm tube lens.
That would improve your results probably.

Actually, the opposite is true when the corners are seriously degraded. Using a longer tube lens is the best way to improve corner quality. There may be a slight cost in center sharpness, but that is only because of the extra magnification.

We need to get away from the idea that the reference focal length tube lens is anything other than that-- this is the focal length that gives the rated magnification, nothing else. If you have a small sensor. you'll get much better results using a shorter focal length, and if you have a very large sensor, you'll get much better results using a longer focal length.

[Scarodactyl]

(In a maybe similar case, when I got a pair of Nikon CFW eyepieces I was very surprised to see that they are compensating (orange halo...) although in a much lower quantity than the Leitz and Zeiss I was used to. This could explain the small but present amount of radial CA present in CF finite objectives, even if Plan Apo)

The cfws are known to add a few aberrations of their own. Nikon sold a much more expensive variant which was better corrected but they never show up because nobody bought them.

[Macro_Cosmos]

I'd expect it to be other way around, since designing a low power objective would be much easier task, than higher.

I don't think so, I think it's the opposite. Lower power ones are harder to design. However, 4x isn't exactly "low" or expensive. If you look at the prices of 2.5x, 1.5x and 1x objectives, they are extremely expensive and seem pretty large for what they are.

I have the 4x UPlanFL N too, still waiting for a reasonable SApo. I'll post some text photos in a bit.

[Macro_Cosmos]

I had always considered the coverage of these particular objectives to be good, expecting a potentially slight fall-off in the corners because the designated 26.5mm image circle is smaller than the 28mm diagonal of my sensor. However, I recently saw that Olympus offers two versions of their tube lenses , a super-wide field tube lense (SWTLU-C), advertised as having a full 26.5mm image circle, and a single port tube lens (U-TLU), which only gives 22mm.
https://www.edmundoptics.com/p/Olympus- ... gKfL_D_BwE
https://www.olympus-lifescience.com/en/ ... ts/swtlu-c

A brochure for that tube lens can be found here: https://www.olympus-ims.com/en/.downloa ... _US&inline
It's cheaper than the U-TLU, which surprises me. There's also a U-SWTLU-SP which is $4075 (yes, four thousand), it uses ecoglass. Not sure if there's a pictorial difference.
I'll be ordering the SWTLU later down the road, need to sell some junk first.

Integrating this thing into my microscope is going to be a massive headache. M41x0.5????? How is that standard? No dovetail for mounting?????? No threads on the other end?!?! How on earth am I going to adapt this (frankly absurdly designed) thing without $200 in adaptors? Urgh, reluctant to buy it now.

[Duke]

Here's the picture of Flash-memory chip (1 GB) with Olympus UPlanFL N 4x 0.13. Shot with Pentax KP (Pixel Shift Resolution/Image stabilization off).

*CLICK HERE FOR ORGINAL RESOLUTION*

While I'm at it, why don't I post my other Olympus LMPlanFL N 10x 0.25:

*CLICK HERE FOR ORGINAL RESOLUTION*

And Olympus LMPlanFL N 20x 0.40:

*CLICK HERE FOR ORGINAL RESOLUTION*

[Macro_Cosmos]

Here we go.
To put it nicely, not so hot in those corners. (Expected, the UIS one I had is even worse)
Nikon Z6, LWD condenser configured for Kohler.