DIC Question

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
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LouiseScot
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Re: DIC Question

#31 Post by LouiseScot » Fri May 21, 2021 7:30 pm

Oh well, I couldn't wait! Here is a diatom taken with the UIS2 40x objective. It's a 100% crop from my Canon 550d:

Diatoms_40x_Crop100pc_0125.jpg
Diatoms_40x_Crop100pc_0125.jpg (37.97 KiB) Viewed 285702 times
Better, I think. More work to do.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: DIC Question

#32 Post by LouiseScot » Fri May 21, 2021 7:37 pm

Hobbyst46 wrote:
Fri May 21, 2021 7:27 pm
LouiseScot wrote:
Fri May 21, 2021 7:03 pm
It's marked as 20x/0.40 with an infinity symbol but was sold to me at the time as a DIN finite objective. Even stranger, it has an apparent working distance of about 5mm. Not sure how that happens! :shock: I've been using it because of it's apparent long working distance - makes life a little easier,...
If it is a finite optics 20x0.40 objective, 5mm is a long working distance IMO.
I know - it's very odd! I've not really used it before as I couldn't get a sharp image on a finite scope and can't seem get one on an infinite scope either! I have a Nikon CF 20x on the Swift, which is great. I have a Nikon CFI60 APO 20x infinity objective but I don't like to get it out of it's container! I do intend using it at some point though :) As you can see below/above the Olympus 40x seems ok but I don't have any kind of fine focus mechanism on my DIC prototype.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Scarodactyl
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Re: DIC Question

#33 Post by Scarodactyl » Fri May 21, 2021 11:17 pm

deBult wrote:
Fri May 21, 2021 7:17 pm
Scarodactyl wrote:
Fri May 21, 2021 6:02 pm
deBult wrote:
Fri May 21, 2021 12:35 pm
To my understanding the Olympus UIS2 requires a correction
All UIS/UIS2 olympus infinity objectives are fully internally corrected.
Hmm: from the Olympus guide on selecting objectives:
“ The UIS2 optical system optimally corrects aberration with a dedicated telan lens and an eyepiece so that the coma aberration and flatness are not degraded even when the telan lens exit pupil position is changed by changing the objective lens and telan distance. ”

http://resources.olympus-europa.com/mic ... _0310B.pdf
I can see how it reads that way, but it's just poorly phrased marketing fluff about being infinity corrected from what I can tell

apochronaut
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Re: DIC Question

#34 Post by apochronaut » Sun May 23, 2021 5:40 pm

The term correction can be general or specific. One always has to ask, corrected for what?

If an objective yields an image to a telan lens that is truly, completely corrected, then whatever the purpose of the telan lens is ; whether it be be to install a focal length, magnify, reduce or change the focal length ; it must be done without inducing a change in the objective's corrections. It must be completely neutral in chromatic aberration and all other aberrations and distortions. It cannot therefore be a cemented doublet and must be itself a highly corrected lens purpose built for one simple job, elst it would not be necessary at all.
If the objective is only corrected for certain aberrations, having complete correction for chromatic aberration for instance , then it will still have correction deficiencies for other aberrations and require a very specific telan lens or telan lens/eyepiece combination, critically engineered to impose an equal and opposite condition to that of the objective.
Therefore, irregardless of the degree or degrees of correction of the objective , any telan lens used with it must be matched to the characteristics of those corrections, otherwise it will impose aberrations or distortions on the system.

LouiseScot
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Re: DIC Question

#35 Post by LouiseScot » Sun May 23, 2021 5:52 pm

apochronaut wrote:
Sun May 23, 2021 5:40 pm
The term correction can be general or specific. One always has to ask, corrected for what?

If an objective yields an image to a telan lens that is truly, completely corrected, then whatever the purpose of the telan lens is ; whether it be be to install a focal length, magnify, reduce or change the focal length ; it must be done without inducing a change in the objective's corrections. It must be completely neutral in chromatic aberration and all other aberrations and distortions. It cannot therefore be a cemented doublet and must be itself a highly corrected lens purpose built for one simple job, elst it would not be necessary at all.
If the objective is only corrected for certain aberrations, having complete correction for chromatic aberration for instance , then it will still have correction deficiencies for other aberrations and require a very specific telan lens or telan lens/eyepiece combination, critically engineered to impose an equal and opposite condition to that of the objective.
Therefore, irregardless of the degree or degrees of correction of the objective , any telan lens used with it must be matched to the characteristics of those corrections, otherwise it will impose aberrations or distortions on the system.
Hiya
I believe Nikon CF/CFI and Olympus UIS2 objectives are 'correction-free'. The tube lens is there simply to bring the rays coming from the (infinity) objective to a focus. The tube lenses are relatively long focal lengths i.e. 180mm for Olympus, 200mm for Nikon. The longer focal lengths are less susceptible to aberrations so I think achromatic doublets will likely do the job, certainly if the objectives are themselves only (plan) achromats. Anyway, for my purposes I'm sure they'll do :)
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

deBult
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Re: DIC Question

#36 Post by deBult » Sun May 23, 2021 8:18 pm

From the Olympus website:

https://www.olympus-lifescience.com/en/ ... nityintro/

“ The tube length in infinity-corrected microscopes is referred to as the reference focal length and ranges between 160 and 200 millimeters, depending upon the manufacturer (see Table 1). Correction for optical aberration in infinity systems is accomplished either through the tube lens or the objective(s). Residual lateral chromatic aberration in infinity objectives can be easily compensated by careful tube lens design, but some manufacturers, including Nikon, choose to correct for spherical and chromatic aberrations in the objective lens itself. This is possible because of the development of proprietary new glass formulas that have extremely low dispersions. Still other manufacturers (notably, Zeiss ICS systems) utilize a combination of corrections in both the tube lens and objectives.”

Olympus even sells a seprate Telan / tube lens, to combine with the UIS objectives when using them in a non Olympus optical system.
This of course is because the Telan is not required?

https://www.olympus-lifescience.com/en/ ... _US&inline
Last edited by deBult on Sun May 23, 2021 8:27 pm, edited 2 times in total.

LouiseScot
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Re: DIC Question

#37 Post by LouiseScot » Sun May 23, 2021 8:24 pm

deBult wrote:
Sun May 23, 2021 8:18 pm
From the Olympus website:

“ The tube length in infinity-corrected microscopes is referred to as the reference focal length and ranges between 160 and 200 millimeters, depending upon the manufacturer (see Table 1). Correction for optical aberration in infinity systems is accomplished either through the tube lens or the objective(s). Residual lateral chromatic aberration in infinity objectives can be easily compensated by careful tube lens design, but some manufacturers, including Nikon, choose to correct for spherical and chromatic aberrations in the objective lens itself. This is possible because of the development of proprietary new glass formulas that have extremely low dispersions. Still other manufacturers (notably, Zeiss ICS systems) utilize a combination of corrections in both the tube lens and objectives.”

Olympus even sells a seprate Telan / tube lens, to combine with the UIS objectives when using them in a non Olympus optical system.

This of course is because it is not required as you guys keep repeating?

https://www.olympus-lifescience.com/en/ ... _US&inline
Thorlabs and Edmunds Optics also sell tube lenses separately - at a price, of course!

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

deBult
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Re: DIC Question

#38 Post by deBult » Sun May 23, 2021 8:32 pm

Louise,

the point I'm making is - for optimal optical quality it may be wise to use the optical components in a matched system, usually the same “design period” of a single supplier. Mix and match is not a sound approach in my (limited) experience, YMMV though.

LouiseScot
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Re: DIC Question

#39 Post by LouiseScot » Sun May 23, 2021 9:12 pm

deBult wrote:
Sun May 23, 2021 8:32 pm
Louise,

the point I'm making is - for optimal optical quality it may be wise to use the optical components in a matched system, usually the same “design period” of a single supplier. Mix and match is not a sound approach in my (limited) experience, YMMV though.
Hiya

Well I'm currently using an Olympus 40x plan achro UIS2 objective (I know it's not specified by Olympus for DIC) with a 180mm fl achromatic doublet as a tube lens. It actually seems to work quite well. I've been experimenting with shorter working distances i.e. less than 180mm. There seem to be two distances either side of the 'tube lens' to bear in mind. One is the infinity space or 'pupil distance, and the other is the working distance. I've not found any definite info on how the two can/should be combined. Just that pupil distance should be 50-150mm and working distance should be 130mm with a housing length of ~33mm - for Thorlabs 180mm tube lens. I originally had a working distance of 180mm but I think a smaller distance still works ok - maybe better. Presumably the pupil distance can be varied within the specified limits with no problems.
I've had lots of trouble with camera vibrations as a consequence of relatively long exposures, and problems with focusing on the test slide. I've made an improved slide holder (though still quite crude) and that should help. I've taken the camera off the flimsy tripod so that should help too. Hopefully, tomorrow I'll get some better images - fingers crossed!

Here's a pic I took earlier but before I made the latest changes. It has some interesting effects! (It appears blurrier on here compared to on my monitor it's been downsized from 175KB to 58KB.)
DiatomsCrop2_0130.jpg
DiatomsCrop2_0130.jpg (58.07 KiB) Viewed 285597 times

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

viktor j nilsson
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Re: DIC Question

#40 Post by viktor j nilsson » Sun May 23, 2021 9:28 pm

deBult wrote:
Sun May 23, 2021 8:32 pm
Louise,

the point I'm making is - for optimal optical quality it may be wise to use the optical components in a matched system, usually the same “design period” of a single supplier. Mix and match is not a sound approach in my (limited) experience, YMMV though.
Usually, yes. But lots of folks over at photomacrography.com have shown over and over again that the UIS/UIS2 objectives work just as well, if not better, with non-compensating tube lenses from other manufacturers. Nikon, Olympus and Mitutoyo infinity objectives work really well with each other's tube lenses, as well as with optically "neutral" tube lenses such as Raynox DCR-150, Thorlabs ITL200, Sigma LSA, etc. Of course some combinations work slightly better than others, but I would say that it is rare that the optimal combination is when using it exactly as intended by the manufacturer.

viktor j nilsson
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Re: DIC Question

#41 Post by viktor j nilsson » Sun May 23, 2021 9:45 pm

That said, it would be good to see a clean brightfield image taken without the prisms to see which of the aberrations in the image are caused by the prisms, and which ones are caused by the rest of your setup.

And it really helps to be able to view the back focal plane when you are setting up a DIY DIC system. When I'm trialling different prism combinations I always remove an eyepiece and peek down the tube. It literally takes less than a second to see if a prism combination has any promise whatsoever, or if it's totally off. With one prism in, you see the colored interference fringes at the BFP with a dark central band, then, when you introduce the second prism, the BFP either become evenly colored (match!) or becomes totally covered with thin sharp interference stripes (mismatch).

Not sure what to expect with the Sanderson prisms, but I think you would expect something similar.

Is it impossible to do this your microscope?

LouiseScot
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Re: DIC Question

#42 Post by LouiseScot » Sun May 23, 2021 10:05 pm

viktor j nilsson wrote:
Sun May 23, 2021 9:45 pm
That said, it would be good to see a clean brightfield image taken without the prisms to see which of the aberrations in the image are caused by the prisms, and which ones are caused by the rest of your setup.

And it really helps to be able to view the back focal plane when you are setting up a DIY DIC system. When I'm trialling different prism combinations I always remove an eyepiece and peek down the tube. It literally takes less than a second to see if a prism combination has any promise whatsoever, or if it's totally off. With one prism in, you see the colored interference fringes at the BFP with a dark central band, then, when you introduce the second prism, the BFP either become evenly colored (match!) or becomes totally covered with thin sharp interference stripes (mismatch).

Not sure what to expect with the Sanderson prisms, but I think you would expect something similar.

Is it impossible to do this your microscope?
I wouldn't call it a microscope, exactly! It uses relay optics to (hopefully!) shift the BFP :
RathiFig4.JPG
RathiFig4.JPG (80.04 KiB) Viewed 285591 times

I'll try what you say with viewing through the optical train without the camera lens - thanks for the advice!

This is a pic I took of the setup:
FullLength2_75pc_103926.jpg
FullLength2_75pc_103926.jpg (41.42 KiB) Viewed 285591 times
I've made a few changes since taking that image though it's essentially the same.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Scarodactyl
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Re: DIC Question

#43 Post by Scarodactyl » Sun May 23, 2021 10:09 pm

deBult wrote:
Sun May 23, 2021 8:18 pm
From the Olympus website:
“ The tube length in infinity-corrected microscopes is referred to as the reference focal length and ranges between 160 and 200 millimeters..."
The same guy wrote up these introductory articles for Olympus, Nikon and Zeiss with minor variations (though you can see a few parts where he accidentally praises one brand on another's page, whoops). As such you shouldn't read too much into the specifics.
deBult wrote:
Sun May 23, 2021 8:18 pm
Olympus even sells a seprate Telan / tube lens, to combine with the UIS objectives when using them in a non Olympus optical system.
This of course is because the Telan is not required?
These are not so much for using the objectives on a non-olympus system as they are for incorporating the objectives into an OEM system at the rated magnification. Every major manufacturer offers tube lenses for this purpose, with or without specific corrections, because it's a component you're going to need one way or another and it's nice to have one that works at the rated magnification. And even though specific corrections aren't needed, you do need a lens which is well-corrected in its own right and of the appropriate focal length to get really top results corner to corner on a larger sensor. Which isn't to say all OEM manufacturers go that route--there's one atomic force microscope I've seen partially disassembled that uses an off-the-shelf video lens as a tube lens with a mitutoyo objective.

edit: I see Viktor beat me to the punch. It is a little frustrating to seemingly have to relitigate this every time it comes up here (not meaning to single you ojt here, deBult, more a general thing). I occasionally use Olympus objectives on my Nikon stand and the only incompatibilities are the mismatched parfocal length (especially difficult going back and forth from mitutoyos) and poor epi DIC compatibility (which would be unfair to expect anyway). Planarity and color correction are not a problem.
Last edited by Scarodactyl on Mon May 24, 2021 12:54 am, edited 1 time in total.

Scarodactyl
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Re: DIC Question

#44 Post by Scarodactyl » Sun May 23, 2021 10:14 pm

LouiseScot wrote:
Sun May 23, 2021 9:12 pm
DiatomsCrop2_0130.jpg
This is definitely intriguing, and looks like it's moving in the right direction.
LouiseScot wrote:
Sun May 23, 2021 10:05 pm
This is a pic I took of the setup:
That looks a bit different than I expected--I would guess putting it through two additional lenses after the tube lens might be having a detrimental effect here, assuming the issue isn't in the objective itself. I'll admit I find the diagram a bit confusing too--I'm guessing there is a good reason they don't put the sanderson prism right above the objective but I haven't read the paper yet. I'd also be a bit worried about flare with how narrow it seems to get at some points, though maybe the tubes are flocked?

LouiseScot
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Re: DIC Question

#45 Post by LouiseScot » Sun May 23, 2021 10:27 pm

Scarodactyl wrote:
Sun May 23, 2021 10:14 pm
LouiseScot wrote:
Sun May 23, 2021 9:12 pm
DiatomsCrop2_0130.jpg
This is definitely intriguing, and looks like it's moving in the right direction.
LouiseScot wrote:
Sun May 23, 2021 10:05 pm
This is a pic I took of the setup:
That looks a bit different than I expected--I would guess putting it through two additional lenses after the tube lens might be having a detrimental effect here, assuming the issue isn't in the objective itself. I'll admit I find the diagram a bit confusing too--I'm guessing there is a good reason they don't put the sanderson prism right above the objective but I haven't read the paper yet. I'd also be a bit worried about flare with how narrow it seems to get at some points, though maybe the tubes are flocked?
I hadn't noticed any flare. It's mostly T2/M42 sections plus the 50mm and 60mm finders, and is only narrow at the tube lens sample plane - and that's because I just shoved a a short section of tube between the two sections :) . The BFP is within the objective with the Sanderson Prisms so the relay optics are required to move it to the position indicated in the diagram.
This is only a prototype system I've kinda put together mostly out of parts I already had. I've had to create an infinity microscope out of parts!

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: DIC Question

#46 Post by LouiseScot » Mon May 24, 2021 1:05 pm

viktor j nilsson wrote:
Sun May 23, 2021 9:45 pm
That said, it would be good to see a clean brightfield image taken without the prisms to see which of the aberrations in the image are caused by the prisms, and which ones are caused by the rest of your setup.

And it really helps to be able to view the back focal plane when you are setting up a DIY DIC system. When I'm trialling different prism combinations I always remove an eyepiece and peek down the tube. It literally takes less than a second to see if a prism combination has any promise whatsoever, or if it's totally off. With one prism in, you see the colored interference fringes at the BFP with a dark central band, then, when you introduce the second prism, the BFP either become evenly colored (match!) or becomes totally covered with thin sharp interference stripes (mismatch).

Not sure what to expect with the Sanderson prisms, but I think you would expect something similar.

Is it impossible to do this your microscope?
Hi again

I took a few pics with my slightly improved setup. Focus is still problematic but I can live with that for the moment. Simply peeking down the optical train really only shows what the camera sees. I did a few more tests with and without prisms. It's the objective prism (next to the camera!) that makes the main difference.
I can get a darkish line across the fov with just the condenser prism in place. I can then insert the objective prism and rotate it to get the most even effect (or not). I'm not really getting the pronounced bands that Rathi et al. discuss (their Fig 3). It could be to do with the prism bending moment which I haven't done any real testing with. I'm waiting on a 6mm polycarbonate sheet so I can experiment with Sanderson's 'open frame' design and which Rathi et al. used for their objective prism. At least, though, I am getting some prism effects :) I'm not sure what the angle should be between the prisms and the cross-polarizers but with no prisms in the optical train the output is dark so the prisms are, at least, behaving as polarizers.
I used the prepared (Chinese) Kidney slide this time:

No prisms, polarizers rotated to allow passage of light:
NoPrisms_Crop_53pc0128.jpg
NoPrisms_Crop_53pc0128.jpg (120.18 KiB) Viewed 285542 times

Both prisms. Objective prism rotated to give even field:
Bothg_Crop54pc0131.jpg
Bothg_Crop54pc0131.jpg (118.4 KiB) Viewed 285542 times
Objective Prism only showing dark band which is actually blue? This might indicate bending moment differences - something to investigate!
ObjPrismOnlyAdj_50pc_0130.jpg
ObjPrismOnlyAdj_50pc_0130.jpg (39.71 KiB) Viewed 285542 times
Both prisms but objective prism rotated to show banding (contrast enhanced):
BothUnevenCropAuto_50pc_0128.jpg
BothUnevenCropAuto_50pc_0128.jpg (58.66 KiB) Viewed 285542 times

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: DIC Question

#47 Post by LouiseScot » Mon May 24, 2021 2:36 pm

I did some tightening of the two prisms. I got stronger banding but the colour order doesn't appear to be the same as Rathi et al. Hmm.. I'm doing the open frame design and construction next. Maybe the colours are related to the output of the 3W white LED I'm using?

Slight tightening:
TightenedSlight_Crop_0128.jpg
TightenedSlight_Crop_0128.jpg (27.33 KiB) Viewed 285535 times

More tightening:
Tightened-1_Crop_25pc0129.jpg
Tightened-1_Crop_25pc0129.jpg (33.97 KiB) Viewed 285535 times
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

Hobbyst46
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Re: DIC Question

#48 Post by Hobbyst46 » Mon May 24, 2021 3:49 pm

A KR12 optical filter or (although to a lesser extent) stacked 81B filters in series will suppress the strong blue component of the white LED, although it will not reach the halogen light spectrum.

LouiseScot
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Re: DIC Question

#49 Post by LouiseScot » Mon May 24, 2021 4:27 pm

Hobbyst46 wrote:
Mon May 24, 2021 3:49 pm
A KR12 optical filter or (although to a lesser extent) stacked 81B filters in series will suppress the strong blue component of the white LED, although it will not reach the halogen light spectrum.
Hiya

I don't think I want to suppress anything - just want to make sense of the order of the coloured bands. I'm awaiting some 6mm polycarbonate so I can build the Sanderson open frame. That should help me get orientated and achieve the correct amount of bending moment. I should have done that in the first place but was cutting corners!

Thanks

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: DIC Question

#50 Post by apochronaut » Mon May 24, 2021 4:39 pm

viktor j nilsson wrote:
Sun May 23, 2021 9:28 pm
deBult wrote:
Sun May 23, 2021 8:32 pm
Louise,

the point I'm making is - for optimal optical quality it may be wise to use the optical components in a matched system, usually the same “design period” of a single supplier. Mix and match is not a sound approach in my (limited) experience, YMMV though.
Usually, yes. But lots of folks over at photomacrography.com have shown over and over again that the UIS/UIS2 objectives work just as well, if not better, with non-compensating tube lenses from other manufacturers. Nikon, Olympus and Mitutoyo infinity objectives work really well with each other's tube lenses, as well as with optically "neutral" tube lenses such as Raynox DCR-150, Thorlabs ITL200, Sigma LSA, etc. Of course some combinations work slightly better than others, but I would say that it is rare that the optimal combination is when using it exactly as intended by the manufacturer.
But none of those tube lenses would be achromats, otherwise they would be compensating and all would have to be used at a specific focal length( maybe not the intended one) in order to compensate for any differences they impose in the system, compared to the lens designed by the mfg.

viktor j nilsson
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Re: DIC Question

#51 Post by viktor j nilsson » Mon May 24, 2021 5:07 pm

apochronaut wrote:
Mon May 24, 2021 4:39 pm
viktor j nilsson wrote:
Sun May 23, 2021 9:28 pm
deBult wrote:
Sun May 23, 2021 8:32 pm
Louise,

the point I'm making is - for optimal optical quality it may be wise to use the optical components in a matched system, usually the same “design period” of a single supplier. Mix and match is not a sound approach in my (limited) experience, YMMV though.
Usually, yes. But lots of folks over at photomacrography.com have shown over and over again that the UIS/UIS2 objectives work just as well, if not better, with non-compensating tube lenses from other manufacturers. Nikon, Olympus and Mitutoyo infinity objectives work really well with each other's tube lenses, as well as with optically "neutral" tube lenses such as Raynox DCR-150, Thorlabs ITL200, Sigma LSA, etc. Of course some combinations work slightly better than others, but I would say that it is rare that the optimal combination is when using it exactly as intended by the manufacturer.
But none of those tube lenses would be achromats, otherwise they would be compensating and all would have to be used at a specific focal length( maybe not the intended one) in order to compensate for any differences they impose in the system, compared to the lens designed by the mfg.
When used as a tube lens, these lenses are focused at infinity and stopped down considerably by the objective in front of them. Even a pretty simple achromat design (such as the 2 lens groups, 3 element Raynox DCR-150) evidently perform really well in this configuration, and add very little aberrations of their own. So even if some of them are achromats by design - when used as a primary taking lens - they act as essentially chromatically neutral when used as a tube lens. But again, different tube lenses do perform slightly differently, but differences are slight and it's not always the manufacturer's own tube lens that performs best.

LouiseScot
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Re: DIC Question

#52 Post by LouiseScot » Mon May 24, 2021 5:09 pm

Just to check, I took a pic using a halogen spotlamp (gives off a lot of heat, lol):


SpotlampAuto_20pc 0128.jpg
SpotlampAuto_20pc 0128.jpg (42.04 KiB) Viewed 285510 times

I enhanced it a bit.

And the previous one again to compare:
Tightened-1_Crop_25pcAdj_0129.jpg
Tightened-1_Crop_25pcAdj_0129.jpg (46.82 KiB) Viewed 285510 times
They are different! And appear to be shifted in a relative way..

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: DIC Question

#53 Post by apochronaut » Mon May 24, 2021 5:50 pm

viktor j nilsson wrote:
Mon May 24, 2021 5:07 pm
apochronaut wrote:
Mon May 24, 2021 4:39 pm
viktor j nilsson wrote:
Sun May 23, 2021 9:28 pm


Usually, yes. But lots of folks over at photomacrography.com have shown over and over again that the UIS/UIS2 objectives work just as well, if not better, with non-compensating tube lenses from other manufacturers. Nikon, Olympus and Mitutoyo infinity objectives work really well with each other's tube lenses, as well as with optically "neutral" tube lenses such as Raynox DCR-150, Thorlabs ITL200, Sigma LSA, etc. Of course some combinations work slightly better than others, but I would say that it is rare that the optimal combination is when using it exactly as intended by the manufacturer.
But none of those tube lenses would be achromats, otherwise they would be compensating and all would have to be used at a specific focal length( maybe not the intended one) in order to compensate for any differences they impose in the system, compared to the lens designed by the mfg.
When used as a tube lens, these lenses are focused at infinity and stopped down considerably by the objective in front of them. Even a pretty simple achromat design (such as the 2 lens groups, 3 element Raynox DCR-150) evidently perform really well in this configuration, and add very little aberrations of their own. So even if some of them are achromats by design - when used as a primary taking lens - they act as essentially chromatically neutral when used as a tube lens. But again, different tube lenses do perform slightly differently, but differences are slight and it's not always the manufacturer's own tube lens that performs best.
Sure, stopping down will close off whatever peripheral aberrations that it does in any specific situation and the tube lens is usually thin and of low curvature and the Raynox DCR-150 is a very wide lens so benefits from it's original aperture and is used reversed, so their negative contributions might be considered somewhat benign but achromats are achromats and despite the slight curvature on these lenses, they still induce chromatism. Can you show me examples where tube lenses have been swapped willy nilly between mfg's and used without other modification and produced better results than the original settup?

Hobbyst46
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Re: DIC Question

#54 Post by Hobbyst46 » Mon May 24, 2021 6:08 pm

LouiseScot wrote:
Mon May 24, 2021 5:09 pm
They are different! And appear to be shifted in a relative way..
Yes, I think that the hues reflect the expected source spectrum: The top has a significant cred and orange component, is "warmer", the bottom has almost none of those, and the blue and violet are dominant.

LouiseScot
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Re: DIC Question

#55 Post by LouiseScot » Mon May 24, 2021 6:33 pm

Hobbyst46 wrote:
Mon May 24, 2021 6:08 pm
LouiseScot wrote:
Mon May 24, 2021 5:09 pm
They are different! And appear to be shifted in a relative way..
Yes, I think that the hues reflect the expected source spectrum: The top has a significant cred and orange component, is "warmer", the bottom has almost none of those, and the blue and violet are dominant.
It's supposed to look like this with a halogen bulb:
RathiInterferencePattern.JPG
RathiInterferencePattern.JPG (18.86 KiB) Viewed 285480 times
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

viktor j nilsson
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Re: DIC Question

#56 Post by viktor j nilsson » Mon May 24, 2021 6:50 pm

apochronaut wrote: Sure, stopping down will close off whatever peripheral aberrations that it does in any specific situation and the tube lens is usually thin and of low curvature and the Raynox DCR-150 is a very wide lens so benefits from it's original aperture and is used reversed, so their negative contributions might be considered somewhat benign but achromats are achromats and despite the slight curvature on these lenses, they still induce chromatism. Can you show me examples where tube lenses have been swapped willy nilly between mfg's and used without other modification and produced better results than the original settup?
Sure.
https://www.closeuphotography.com/tube-lens-test

Here's a test where a Mitutoyo 5x objective was used with a bunch of different tube lenses:

Thorlabs ITL200 Tube Lens
Mitutoyo MT-1 Tube lens
Nikon MXA20696 Tube Lens
Reichert Microscope Tube Lens
Canon 250D Close-up Lens
Century Precision Optics +4 Achromatic Diopter Lens
Century Precision Optics +7 Achromatic Diopter Lens
Cosina MMA Matched Macro Adapter Lens
Raynox +4.8 diopter
Raynox +5.9 diopter
Raynox +8 diopter
Sigma LSA Life Size Attachment Lens

The manufacturer's own tube length (Mitutoyo MT-1) performed quite poorly, and the best was the Thorlabs ITL200, which is actually made by Nikon. Interestingly, the Thorlabs-branded but Nikon-made ITL200 tube lens performs quite a bit better with Nikon and Mitutoyo objectives then the Nikon-branded MXA20696 tube lens that Nikon ships with its CFI and CFI2 microscopes...

I don't know of any equally carefully controlled comparisons with an Olympus UIS2 objective, but I've seen plenty of very clean images taken with Olympus objectives and a Raynox DCR-150 as a tube lens.

deBult
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Re: DIC Question

#57 Post by deBult » Mon May 24, 2021 7:54 pm

viktor j nilsson wrote:
Mon May 24, 2021 6:50 pm
I don't know of any equally carefully controlled comparisons with an Olympus UIS2 objective, but I've seen plenty of very clean images taken with Olympus objectives and a Raynox DCR-150 as a tube lens.
Check: clean images with 40* UIS2 objectives? I’m really curious to learn more, Please supply a link.

Best, deBult

viktor j nilsson
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Location: Lund, Sweden

Re: DIC Question

#58 Post by viktor j nilsson » Mon May 24, 2021 8:12 pm

deBult wrote:
Mon May 24, 2021 7:54 pm
viktor j nilsson wrote:
Mon May 24, 2021 6:50 pm
I don't know of any equally carefully controlled comparisons with an Olympus UIS2 objective, but I've seen plenty of very clean images taken with Olympus objectives and a Raynox DCR-150 as a tube lens.
Check: clean images with 40* UIS2 objectives? I’m really curious to learn more, Please supply a link.

Best, deBult
Would need to search a bit to find exactly that, but in the meantime here's a *fairly* clean image taken with an Olympus UMPlanFL 50x 0.80 using a Rodenstock Omegaron 105mm enlarger lens as tube lens:

https://www.photomacrography.net/forum/ ... 27&t=43377

viktor j nilsson
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Location: Lund, Sweden

Re: DIC Question

#59 Post by viktor j nilsson » Mon May 24, 2021 8:16 pm

Here's another one using a Olympus UMPlanFI 50x/0,80 on a Canon EF 70-200L zoom lens as a tube lens:

https://www.photomacrography.net/forum/ ... 9&p=267397

Scarodactyl
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Re: DIC Question

#60 Post by Scarodactyl » Mon May 24, 2021 8:18 pm

This should probably be split off into another discussion. LouiseScot is working on an extremely cool project and I thinj we really don't want to make it harder to discuss by retreading this in her thread.

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