Olympus U TLU tube lens vs SWTR-2 Superwide Head

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Scarodactyl
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Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Scarodactyl »

I recently got an Olympus BX40 which I have been getting fixed up. I got a good deal on a SWTR-2 superwide head which was missing the top dovetail for mounting camera hardware (it also had some issues with the prism slider until I opened it up and removed the plastic bag of bolts that was inside it). I ordered a replacement for the top dovetail from China, but to get the part faster I also ordered a U-TLU which has the same dovetail attachment. In the mean time I also made a 3D printed M42 adapter so I could easily attach my camera for direct projection. The scope also came with an attachment for a teaching head which produces an image that easily covers aps-c, so I ordered an M45x0.74 to M42 adapter from RAF so I could attach my camera to it too. My idea was to do a triple test: it's been said here before that the U-TLU doesn't perform as well in the periphery as the tube lens in the SWTR head, which makes a lot of sense but didn't have any photos attached, and while I had the hardware both would make a great point of comparison for the teaching attachment. Trinocular Olympus infinity heads are way overpriced on the secondary market (vs, say, Nikon), and superwide ones triply so, so a potential inexpensive alternative seemed worth pursuing. The last adapter came in today, so I sorted through my meager collection of prepared slides and found one with enough detail--I only have some leftover reference samples of different kinds of fibers I got at an estate sale, but one of them had delaminated and the mountant recrystallized, making a beautiful slide for crossed polarized photography. The scope came with an analyzer slider, and I put a simple film polarizer over the field lens. I took photos with the analyzer in and out.
The objective used is an Olympus UPlanFL 10x/0.30.

Note the title of the thread doesn't even mention the teaching head, because the teaching head gave a really bad image. It's a bit enlarged relative to direct projection off of either of the others and there's a ton of weird chromatic aberrations, unlike any I've seen before. Here's a center crop with the analyzer out:
Image
Yeah, so that's a nonstarter for pretty much any purpose. Anyone ever seen that type of aberration before? I assume there are more optics in the attachment that would hold a second head, maybe compensating for whatever that is.
So that left me with a more obvious comparison, but it could be useful anyway.
Overview stacks on the U TLU (click for full size)
Image
Image

And the SWTR:
Image
Image

Both deliver plenty of image to cover aps-C, let's look at some crops. U-TLU on the left SWTR on the right. These are from single images, I tried to do my best to match the focal point (it was a fairly deep set of crystals).
Image Image

Image Image
Center Crops^

Image Image

Image Image
Edge Crops^

Image Image

Image Image
Corner Crops^

Basically, it seems like at the center they're identical, at the edge they're pretty close but maybe a little more CA is creeping in on the U TLU. The difference is, however, obvious in the far corners where the SWTR continues to show excellent color correction while the U-TLU degrades a bit on that front. The SWTR also has a bit more detail and a crisper image, though this is a bit more obvious in the stacks:

Image Image

Corner crops of the stacked images^

Overall it's about what you'd expect I guess--the U TLU is cheap, plentiful and really doesn't do that bad, but the extra money that a superwide head costs definitely results in a better image. That said the normal asking prices for them are ridiculous so it's hardly something I'd recommend seeking out unless you find a great deal.

Duke
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Duke »

Scarodactyl, thx for the test.
Do you still have Nikon CFI-UW trinocular (Optiphot 150/200/300) at your disposal?
I believe it has the same MXA20696 "CFI60-2,CFI60,CF&IC compatible" f=200mm UW tubelens, as used in newer Eclipse heads.
Can you run a test between Nikon CFI-UW and Olympus SWTR?
“Thoroughly conscious ignorance is the prelude to every real advance in science.” - JCM

Scarodactyl
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Scarodactyl »

The infinity optiphot head I have isn't technically ultra wide, but I think it has the same tube lens as the ultrawide one since it's physically wide (same width as an ultra wide one), seems to have the same elements as an ultra wide and does very well on direct projection on aps c. I could 3d print an adapter to put it on the BX40 and give that a try too.

Duke
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Duke »

Scarodactyl wrote:
Fri Mar 05, 2021 12:41 am
The infinity optiphot head I have isn't technically ultra wide...
How come it's not UW? Is binocular part design limits FOV or does it have 23mm eyepiece sockets?
I've seen heads that look identical to LV-TI of mine, but with different eyepiece sockets, is yours one of those?
Thought that that maybe there're 23->30mm adapters, and you can screw them out.
“Thoroughly conscious ignorance is the prelude to every real advance in science.” - JCM

Scarodactyl
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Scarodactyl »

Yeah, it just has 23mm sockets. I am going to try transplanting an UW binocular onto it at some point, since the bolts holes are the same, but for now I just use 10x/22 eyepieces which are pretty good.

Ichthyophthirius
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Ichthyophthirius »

Scarodactyl wrote:
Thu Mar 04, 2021 11:37 pm
The scope came with an analyzer slider, and I put a simple film polarizer over the field lens. I took photos with the analyzer in and out.
Hi,

Did you take the polariser over the field lens out as well?

Using polarised light in brightfield can cause problems via internal refections in the trinocular tube. So they sometimes have a built-in depolariser. The U-TLU doens't have a depolariser. So maybe this is related to the colour fringes you see?

Scarodactyl
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Scarodactyl »

In theory it can cause issues in microscope heads where there are mirrors and/or prisms with flat surfaces. The U TLU doesn't have any of those, just a single lens, so I think it would be unlikely to cause any issues. In particular I think it's unlikely that it would manifest as a mushier, more aberrated image at the periphery with the center and edge giving nearly identical results.

Ichthyophthirius
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Ichthyophthirius »

Ah, I see. So that only affects the corners and the sides are much better?

Maybe then it's just a spec issue? Does Olympus say anything about the expected sensor size on the U-TLU? Maybe it's just enough for m4/3, their own cameras. Then it would make sense that the SW head covers a much wider area than the camera tube.

Scarodactyl
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by Scarodactyl »

I think they offer a variant for superwide imaging, so presumably the original isn't specced for it. It really isn't surprising since so few microscopy customers seem care about that, and with that in mind I think its performance is surprisingly good.
In the end it's an obvious and unexciting test result, and it wasn't really what I was setting out to test, but the topic has come up in the past.

pbraub
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by pbraub »

Thank you for this test. It is really helpful (i have been one of the guys suggesting that the superwide heads might deliver better quality at the edges of the image but never had the time to formally test it).

Officially the TLU is for 22 mm but it odes not surprise me that it works beyond that. many of the oly components perform ok outside of the immediate specs (many of the fn22 objectives work ok on the superwide tube, however unfortunately not the trino tubes with fn26.5 eyepieces :-()

The super wide variant is the swtlu-c (https://www.olympus-ims.com/en/component/swtlu-c/) which can be bought at edmund optics to ok-ish price). I recently saw the lens pop up in custom designs such as the SQUID Imaging microscope linked to a couple of weeks back.

The swtlu is mounted with m41/.5 threads. Is anyone aware of an adapter that allows mounting to SM2 or other more hobbyist accessible threads?

Peter

josefbauer
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by josefbauer »

Thanks for the comparison!
FYI:
There is now a super wide version of the U-TLU available. It is called U-SWATLU and works with the same adapters like the U-TLU.

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dmillard
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Re: Olympus U TLU tube lens vs SWTR-2 Superwide Head

Post by dmillard »

For Peter and anyone else who wanted to incorporate the SWTLU-C tube lens into a Thorlabs SM2 system, RafCamera offers an M41x0.5♀ to SM2♂ adapter, although I have no idea what issues there may be with shipping at this time.

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