What is a good specimen or procedure to test quality of phase contrast?

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lperepol
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What is a good specimen or procedure to test quality of phase contrast?

#1 Post by lperepol » Sat Dec 29, 2018 1:33 pm

Looking for some good specimens, pictures, procedures to compare against and quantify the quality of phase contrast.
1) OMAX 40X-2500X 18MP USB3 Plan Phase Contrast Trinocular LED with Turret Phase Disk
2) AmScope Trinocular Stereo, 3.5X-90X Magnification Four-Zone LED Ring Light

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75RR
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Re: What is a good specimen or procedure to test quality of phase contrast?

#2 Post by 75RR » Sat Dec 29, 2018 1:51 pm

The quality of Phase Contrast tends to have more to do with the quality of the objective than in the "type" of Phase Contrast being used.

Zeiss for example in their 160 tube range have Phase in archromat, Planachromat, Neofuar, Plan-Neofluar and Planapo objectives.

They thus give you the choice of simply selling your dog to purchase their more economical Phase range or hocking your children as well if you aspire to Phase Planapos.

I say type of Phase Contrast because although nowadays most manufacturers basically have one.
There was a time, shortly after Phase Contrast was invented in the mid fifties that some manufactures spent a lot of time and effort developing several variations of it.
American Optical with their Dark Phase and Bright Phase perhaps foremost among them.

Mic-UK is an excellent resource for just about anything to do with microscopy.

Type in Phase Contrast in the search box and change Category to Micscape & Microcopy-uk

http://www.mic-uk.info/cgi-bin/search.cgi

This article on using diatoms to quantify an objective's resolution is very much worth reading. It mentions the effect Phase Contrast has on NA as well.

http://www.microscopy-uk.org.uk/mag/ind ... -test.html
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

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coominya
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Re: What is a good specimen or procedure to test quality of phase contrast?

#3 Post by coominya » Mon Dec 31, 2018 8:09 am

I would type "phase contrast" into bing images and see what comes up. Then select the most prolific examples and find them in your local environment. Thus you will have many online images to compare with your own test subjects.
Following the page link off bing will often lead to a good writeup as well.

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ImperatorRex
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Re: What is a good specimen or procedure to test quality of phase contrast?

#4 Post by ImperatorRex » Mon Dec 31, 2018 10:24 am

You can instantly create your own specimen with epitel cells obtained from your mouth. Also you will find images to compare, e.g. https://www.microscopyu.com/gallery-ima ... lial-cells.

Zeiss seems to provide specimens from "young mice" cross section cuts as PHACO specimen. See foto attached.
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