OK what about Zeiss standard DIC?

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rjlittlefield
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Re: OK what about Zeiss standard DIC?

Post by rjlittlefield »

viktor j nilsson wrote:
Sun Dec 11, 2022 8:32 am
I'd be happy to dig out my laser pointer and set up my optical bench again to try to see if I can figure it out. And by optical bench I mean a ruler, a caliper, and a couple of dabs of Blu-tack to hold things in place.
That sounds quite like the setup I use. :)

I am only curious. If you are curious also, then I would like to hear what you find out. Otherwise I am happy to leave the old data as a mystery.

--Rik

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Re:

Post by Macro_Cosmos »

viktor j nilsson wrote:
Fri Feb 01, 2019 7:07 am
Thanks, I think I understand a bit more now. I was confused because some places online claim to show Nomarski prisms but actually show Wollaston prisms located exactly at the rear focal plane. This one for example:

Image

In this case, the objective-side prism must be located exactly at the rear focal plane. I had to look around a bit for an illustration that actually showed Nomarski prisms and found this:

Image

So when we have a Nomarski prism, it's the front interference plane of the objective-side prism that must coincide with the objective rear focal plane - not the prism itself. Correct?

Image sources:
https://www.researchgate.net/figure/Exp ... 190278/amp

http://microscopy.berkeley.edu/courses/ ... asdic.html
I somehow missed an entire page. Anyway, thanks for bringing this up.
Page 5 and 6 here: https://www.slideshare.net/SARAVANA3061987/nomarski-dic

A lot of literature display the schematic of a Wallaston prism based DIC and simply relabel the prisms as Nomarski which does not make a difference to most people.
Image

blekenbleu
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Re: Re:

Post by blekenbleu »

viktor j nilsson wrote:
Fri Feb 01, 2019 7:07 am
So when we have a Nomarski prism, it's the front interference plane of the objective-side prism that must coincide with the objective rear focal plane - not the prism itself. Correct?
That is my impression.
Macro_Cosmos wrote:
Sun Dec 11, 2022 3:12 pm
A lot of literature display the schematic of a Wallaston prism based DIC and simply relabel the prisms as Nomarski which does not make a difference to most people.
It appears that repurposing objective (Nomarski) prisms to use in condenser turrets is not ideal,
since those turrets seemingly are at the condenser focal plane, where a Wollaston prism is wanted,
at least in Nikon's implementations:
https://www.microscopyu.com/tutorials/w ... marski-dic
Metaphot, Optiphot 1, 66; AO 10, 120, and EPIStar 2571
https://blekenbleu.github.io/microscope

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Re: OK what about Zeiss standard DIC?

Post by Pau »

Macro_Cosmos wrote:
Sat Dec 10, 2022 10:06 pm
The shear angle of the normal type Olympus DIC slider prism (U-DICT, U-DICTS, WI-DICT) is 74µrad. Nikon's fitted nosepiece objective-specific prism is 76µrad and Zeiss is 71µrad.
Where did you found this numbers?
I've only found a single reference:
At Shribak, M. (2013) Quantitative orientation-independent DIC microscope with fast switching shear direction and bias modulation
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3695724/ there is a measured table of modern Olympus objective prisms (table 1)
Assuming the normal DIC is being used.
Leica: higher contrast, common nosepiece slider with condenser prisms for specific objetives.
Nikon and Zeiss: contrast and resolution balanced, most people prefer the look of these two. Each objective has its own slider while condenser prisms are tailored for different NA.
Olympus: Between Leica and Nikon/Zeiss. Common nosepiece slider with condenser prisms for specific objectives. High contrast at lower magnifications while contrast and resolution is balanced at higher magnifications.
Very interesting info!
Could you kindly explain the graph?
Measuring this number is rather tricky, hopefully, I settle down enough and build something to do that next year. If I get all the numbers accurately measured, mixing and matching prisms from different brands even could become a possibility.
That would be great!
Pau

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Re: OK what about Zeiss standard DIC?

Post by Macro_Cosmos »

Pau wrote:
Thu Dec 22, 2022 11:04 am
Macro_Cosmos wrote:
Sat Dec 10, 2022 10:06 pm
The shear angle of the normal type Olympus DIC slider prism (U-DICT, U-DICTS, WI-DICT) is 74µrad. Nikon's fitted nosepiece objective-specific prism is 76µrad and Zeiss is 71µrad.
Where did you found this numbers?
I've only found a single reference:
At Shribak, M. (2013) Quantitative orientation-independent DIC microscope with fast switching shear direction and bias modulation
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3695724/ there is a measured table of modern Olympus objective prisms (table 1)
Assuming the normal DIC is being used.
Leica: higher contrast, common nosepiece slider with condenser prisms for specific objetives.
Nikon and Zeiss: contrast and resolution balanced, most people prefer the look of these two. Each objective has its own slider while condenser prisms are tailored for different NA.
Olympus: Between Leica and Nikon/Zeiss. Common nosepiece slider with condenser prisms for specific objectives. High contrast at lower magnifications while contrast and resolution is balanced at higher magnifications.
Very interesting info!
Could you kindly explain the graph?
Measuring this number is rather tricky, hopefully, I settle down enough and build something to do that next year. If I get all the numbers accurately measured, mixing and matching prisms from different brands even could become a possibility.
That would be great!
Hi Pau,
1. Yes, the paper is where the information comes from. Very helpful to get a more-than-layman's understanding of DIC.
2. The graph is simple: higher resolution = lower contrast and vice versa. It simply means that Leica offers the most contrast, Nikon is the most balanced, Zeiss is also very balanced, and Olympus offers high contrast at low magnification and balanced for high magnification.

This inevitably means DIC from different manufactures cannot be compared as it is up to the manufacturer's discretion to optimise their DIC according to their worldview of the best balance. Nikon argues that their balanced ones are the best and people drool over Zeiss, but this is nothing but gear snobbery. Nikon's balanced approach to me, works well for video work, same as Zeiss. Evident's offering to be is the best as they have variants that are optimised for different samples, until they discontinued all oil immersion prisms. Funnily, Olympus' high resolution DIC at 10x is the same resolution as Zeiss' normal type, this is why many people are misled into believing Zeiss and Nikon has more resolution, correct conclusion but it is complicated.

If you want to know the source of the graph, it is from internal marketing strategy documents that landed on me, I cannot and will not share them. I have chosen to make the graph "public" because I am frankly sick of all the misinformation out there.

Perl
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Re: OK what about Zeiss standard DIC?

Post by Perl »

Hi
Go for Leitz ICT system then you dont have the delamination Problem !
****** Seeing is Believing ******

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