I have a Nikon Model G and wish to use phase contrast.
Something I read onetime led me to believe I could set this up at home just with a couple of pieces of polarising filter and so I bought some. It's like paper. Or plastic. Just cut out the piece you want.
I've lost that original reference and am not sure how to set it up so I'm asking here if there's anyone with experience/advice regarding this.
My thought is that I would put one filter in the little filter cap that goes beneath the condenser.
Then a second one - where? It should be on the other side of the objective I think, right?
So somehow I have to get it into the ocular tube, above the objective?
I'm googling around but so far I'm just getting information about microscopes specifically designed, or incorporating lenses and such specifically designed for phase contrast. No directions on a DIY setup such as I'm proposing.
How To Set Up DIY Phase Contrast?
Re: How To Set Up DIY Phase Contrast?
I think that what you are referring to as Phase is in fact Polarized.
See link: http://www.microscopy-uk.org.uk/mag/ind ... polar.html
See link: http://www.microscopy-uk.org.uk/mag/ind ... polar.html
Last edited by 75RR on Mon Jun 22, 2015 11:05 pm, edited 1 time in total.
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)
Olympus E-P2 (Micro Four Thirds Camera)
Re: How To Set Up DIY Phase Contrast?
Agree with 75RR. What you are describing is a polarizing set up which can yield some very interesting views.
Re: How To Set Up DIY Phase Contrast?
If I may suggest something that is both very easy and very effective to visualize the stuff in your water: oblique illumination.
If you are thinking of cross-polarized light, then what you said is correct. I would put the bottom ("polarizer") on top of the light port if it won't get too hot there, as it will be more easily accessible to be rotated to get extinction. The top one ("analyzer") can be anywhere above the objective. I couldn't find a description of your microscope, so it is hard to suggest a place, but you can put it on top of the eyepiece (if it is a monocular), for example. If the microscope head is removable, you can put it under the head. I would avoid putting it in the eyepiece itself where a graticule would go, as any dust or scratches will show up in focus, making it difficult to tell what is dust/scratches and what is something of interest. Having said that, for your purposes I think I would first try oblique illumination.
If you are thinking of cross-polarized light, then what you said is correct. I would put the bottom ("polarizer") on top of the light port if it won't get too hot there, as it will be more easily accessible to be rotated to get extinction. The top one ("analyzer") can be anywhere above the objective. I couldn't find a description of your microscope, so it is hard to suggest a place, but you can put it on top of the eyepiece (if it is a monocular), for example. If the microscope head is removable, you can put it under the head. I would avoid putting it in the eyepiece itself where a graticule would go, as any dust or scratches will show up in focus, making it difficult to tell what is dust/scratches and what is something of interest. Having said that, for your purposes I think I would first try oblique illumination.
Re: How To Set Up DIY Phase Contrast?
Hello all,
I have read a few things about DIY phase contrast on a couple different groups, but I am skeptical. The phase ring that is on (or above) the back lens of the objective is of very specific design and placement so that it will yield a good contrast positive or negative contrast. I have not yet figured out how one would do this at the dining room table, but because I have not figured it out does not mean it will not happen. I can see how one could create the necessary mask for an existing objective. If I were doing something of this sort I would find an objective and make the mask, or find a compatible set that will fit the microscope.
As gekko said, polarizing on this scope is fairly simple. The polarizer can sit on top of the illuminator where it can be easily rotated. The analyzer can be placed directly beneath the removable body. If plastic is used for the polarizer it is important to pay attention to heat. If glass is used the heat is not so critical.
I do agree with gekko that oblique illumination is an easy and effective method that offers some interesting images as it creates the shadows. In some ways the images produced by oblique illumination resemble those created by DIC and like DIC may suggest features that may not be as they are seen.
I shudder when I remember how we were reprimanded in school when we did not have the hole in the disc diaphragm properly centered.
lorez
I have read a few things about DIY phase contrast on a couple different groups, but I am skeptical. The phase ring that is on (or above) the back lens of the objective is of very specific design and placement so that it will yield a good contrast positive or negative contrast. I have not yet figured out how one would do this at the dining room table, but because I have not figured it out does not mean it will not happen. I can see how one could create the necessary mask for an existing objective. If I were doing something of this sort I would find an objective and make the mask, or find a compatible set that will fit the microscope.
As gekko said, polarizing on this scope is fairly simple. The polarizer can sit on top of the illuminator where it can be easily rotated. The analyzer can be placed directly beneath the removable body. If plastic is used for the polarizer it is important to pay attention to heat. If glass is used the heat is not so critical.
I do agree with gekko that oblique illumination is an easy and effective method that offers some interesting images as it creates the shadows. In some ways the images produced by oblique illumination resemble those created by DIC and like DIC may suggest features that may not be as they are seen.
I shudder when I remember how we were reprimanded in school when we did not have the hole in the disc diaphragm properly centered.
lorez