Cover slip / coverslip thickness / correction / effect

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abednego1995
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Post by abednego1995 »

Going into patents gives some hints. Mr.Margolis happens to be the CEO of infinity usa.

https://patentimages.storage.googleapis ... 3864A1.pdf

Medwar
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Post by Medwar »

Thanks a lot! This paper really gives more information. However after fast-reading I still failed to find an answer what are the limits of such correction, maximum thickness that can be corrected, with dependancy to NA and RI.

abednego1995
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Post by abednego1995 »

Well, there would be physical constraints and design goals that would be in the way in using an objective outside its intended parameters. (You could also have some firm design a special objective if your pockets allow...)

However, if the problem you are facing is just peering through 2mm of nd=1.7 (pleurax?) medium without a coverglass you could use an objective that has a correction collar with WD greater than 2mm. The collar compensation numbers are adjusted for nd=1.51 glass, so divide that with 1.7 and multiply it with the real depth.
That would be the amount of correction on the collar. This although has no regard to the dispertion difference the media has to glass, so I don't expect it to be too pretty in white light.

This would probably limit your available objective options to around max NA0.6 with ELWD objectives with correction collars. The max RI? Not sure, but I'd love to see experimental results :-)

Cheers,
John

bokemon
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Re: Cover slip / coverslip thickness / correction / effect

Post by bokemon »

Hello,
2022 bump.
Will using spherical aberration correction plates work?

Macro_Cosmos
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Re: Cover slip / coverslip thickness / correction / effect

Post by Macro_Cosmos »

bokemon wrote:
Tue Jan 18, 2022 7:51 am
Hello,
2022 bump.
Will using spherical aberration correction plates work?
Wait, for improper coverslip thickness, and embedding medium that is too thick either due to inadequate preparation or just inherently thick specimens?
No, that will not work -- provided I do not know much about this subject as it is rather recent. So consider the following a somewhat educated opinion.

To use spherical aberration correction optics, you need to figure out the amount induced first, which will differ from sample to sample. These plates are like $500+ a piece, if you want to correct for many wavefront errors, the cost is going to be unimaginable. With that kind of money, it is better to just invest in a high power objective with a correction collar. (40x UPlanSApo, $600 used)
These plates are designed for small field of view systems, with spot-sized subjects, like LASERs.

For microscopy, the industry trend is adaptive optics (AO), long used in astronomy imaging. Eric Betzig had a couple nice quotes for this, one will be far too profane for the forum. The other was "with AO, the best ground-based telescopes in the infrared kick the ##### of the Hubble Space Telescope". He also had some nice words regarding LSCM, calling it a device that "leaves death and destruction".

bokemon
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Re: Cover slip / coverslip thickness / correction / effect

Post by bokemon »

I was thinking more like a NA 0.21 (e.g. Mitutoyo 5x HR or 7.5X) objective looking thru 3mm glass, which gives about a half wave error.
Is this an actual problem or no? I don't have any real life datapoints on this except the guy at Infinity said that 0.2 NA was good for "several millimeters and people do this all the time with no problems..."
Also, it's not fair to compare a new correction plate to a used objective, especially when the typical correction collars are only used to fix a fraction of a millimeter error.

Scarodactyl
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Re: Cover slip / coverslip thickness / correction / effect

Post by Scarodactyl »

bokemon wrote:
Mon Jan 24, 2022 5:54 am
Also, it's not fair to compare a new correction plate to a used objective, especially when the typical correction collars are only used to fix a fraction of a millimeter error.
It would be less fair if used correction plates were readily available, but I haven't seen one myself. As such it's like to like in terms of what avenues are available to the enthusiast*. Correction collars on lwd objectives at lower mags will typically go from 0-2mm which isn't too bad anyway, though not up to 3mm that I've seen.

*if you have researchbuxx of course you can get what you want.
bokemon wrote:
Mon Jan 24, 2022 5:54 am
I was thinking more like a NA 0.21 (e.g. Mitutoyo 5x HR or 7.5X) objective looking thru 3mm glass, which gives about a half wave error.
Is this an actual problem or no?
I suspect this is not a problem. Mitutoyo does offer variants of their objectives corrected for 3.5mm cover glass (g plan apo) but they are only offered for 20x and up.

Lou Jost
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Re: Cover slip / coverslip thickness / correction / effect

Post by Lou Jost »

"Mitutoyo does offer variants of their objectives corrected for 3.5mm cover glass (g plan apo) but they are only offered for 20x and up."

In addition, other major objective makers also offer objectives corrected for specific thick glass. Reichert, Nikon, and Olympus all have such offerings, often listed as "LCD" or something like that, because they are used to look for faults in thick LCD displays. In the case of Reichert they are designed to image very hot things through a quartz window.

Other lenses designed to image through thick glass include any MFT lens reversed (4.2mm), and some x-ray lenses.

Scarodactyl
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Re: Cover slip / coverslip thickness / correction / effect

Post by Scarodactyl »

This is true, though I have found it a bit difficult to find the specific thickness in some cases. The Nikon lcd spec I could find (for their current cf plan 20x and 50x offerings) only went up to 1.2mm, less than their normal lwd fluor's correction collar.

Macro_Cosmos
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Re: Cover slip / coverslip thickness / correction / effect

Post by Macro_Cosmos »

bokemon wrote:
Mon Jan 24, 2022 5:54 am
I was thinking more like a NA 0.21 (e.g. Mitutoyo 5x HR or 7.5X) objective looking thru 3mm glass, which gives about a half wave error.
Is this an actual problem or no? I don't have any real life datapoints on this except the guy at Infinity said that 0.2 NA was good for "several millimeters and people do this all the time with no problems..."
Also, it's not fair to compare a new correction plate to a used objective, especially when the typical correction collars are only used to fix a fraction of a millimeter error.
Get him or her to define "no problems", because "several" implies a lot of things. 0.5 or 1mm? Sure, 10mm? I think that will pose issues.
It was completely fair given the context, none of us knew it was 3mm thick glass until now. Either way, these plates are designed for point sources. You will have better chances asking EO since it is a rather recent product.

I think 3mm at an NA of 0.2 will be an issue. Typical microscope glass slides are 1mm, stack 3 of them and bond with UV glue. Not ideal but fair. Biological objectives with high NA offers a correction collar for 0.13-0.23mm coverslips, inverted microscope objectives go from 0-2mm. No idea about those LCD ones.


bokemon
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Re: Cover slip / coverslip thickness / correction / effect

Post by bokemon »

Hello folks,
Several months later bump.
I had set up a system with Mitutoyo M plan 5x and 10x with reversed Raynox (WeMacro) and an astronomy camera for the fast datalogging.
I'm pleased to report that the 10x, with NA .28, only takes a small hit to image quality in the center with a 3mm glass window. So whatever the SA turns out to be...
The image quality in the corners (4/3 sensor) takes a bigger hit from the window, but it only appears to be about 2-3 pixels worth of lateral chromatic aberration, so possibly fixable in software.
Besides the Infocus from infinityUSA, does anybody know of a aftermarket add-on spherical aberration corrector?
I also failed to find a correction collar objective that had similar specs to the Mitu 10x in terms of working distance.

Scarodactyl
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Re: Cover slip / coverslip thickness / correction / effect

Post by Scarodactyl »

One exists (if you're a baller with a huge budget)
https://www.thorlabs.com/thorproduct.cf ... r=TL10X-2P
Not quite to 3mm.
Or you could get one of the top end current gen stereo microscopes or macroscopes with a correction collar (if you're an even wealthier baller).
Otherwise no, it isn't done much. You could go for a lower NA 10x objective which will care less. You can also adjust the focus on the tube lens to alter the behavior of the objective, as has been discussed for the 0.4mm corrected oem nikon 20x plan apos.

Macro_Cosmos
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Re: Cover slip / coverslip thickness / correction / effect

Post by Macro_Cosmos »

bokemon wrote:
Wed Aug 31, 2022 6:08 pm
Hello folks,
Several months later bump.
I had set up a system with Mitutoyo M plan 5x and 10x with reversed Raynox (WeMacro) and an astronomy camera for the fast datalogging.
I'm pleased to report that the 10x, with NA .28, only takes a small hit to image quality in the center with a 3mm glass window. So whatever the SA turns out to be...
The image quality in the corners (4/3 sensor) takes a bigger hit from the window, but it only appears to be about 2-3 pixels worth of lateral chromatic aberration, so possibly fixable in software.
Besides the Infocus from infinityUSA, does anybody know of a aftermarket add-on spherical aberration corrector?
I also failed to find a correction collar objective that had similar specs to the Mitu 10x in terms of working distance.
If you do not mind a 20x, Olympus offers objectives for an inverted system with a CC of 0-2mm.
An LCD Plan seems like a good candidate for your application as well, considering that the window is 3mm.
Not cheap on those sites, but I have seen many good deals.

bokemon
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Re: Cover slip / coverslip thickness / correction / effect

Post by bokemon »

Scarodactyl wrote:
Wed Aug 31, 2022 8:39 pm
One exists (if you're a baller with a huge budget)
https://www.thorlabs.com/thorproduct.cf ... r=TL10X-2P
Not quite to 3mm.
Or you could get one of the top end current gen stereo microscopes or macroscopes with a correction collar (if you're an even wealthier baller).
Otherwise no, it isn't done much. You could go for a lower NA 10x objective which will care less. You can also adjust the focus on the tube lens to alter the behavior of the objective, as has been discussed for the 0.4mm corrected oem nikon 20x plan apos.
Unfortunately that one won't work because the working distance is too short. (The mitutoyo one was 30-something mm)
Also, our lab already has a Mitu G plan 20x with the 3.5mm glass compensation but I haven't bothered to try it out because the FOV gets smaller but the resolution doesn't get better (NA still 0.28)
I will look into this thing about using the objective in non-infinity focus mode, but we do have an epi illuminator (45 degree mirror in light path) so I doubt I can make it too non-infinity.

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