An alternative to Kohler?

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
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MicroMan2
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An alternative to Kohler?

#1 Post by MicroMan2 » Mon Jul 03, 2017 8:26 pm

My microscope is a no name without a field diaphragm or collector lens so Kohler is impossible? Would anyone inquire other methods of reducing uneven illumination when taking pictures? I was thinking of using a ground glass diffuser but I'm not sure about other approaches.

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zzffnn
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Re: An alternative to Kohler?

#2 Post by zzffnn » Mon Jul 03, 2017 8:33 pm

Diffusion with frosted glass, milk jug piece or vellum paper (or even office paper dipped with oil) should work.
Last edited by zzffnn on Sat Jul 08, 2017 7:47 pm, edited 1 time in total.

MicroMan2
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Re: An alternative to Kohler?

#3 Post by MicroMan2 » Mon Jul 03, 2017 9:01 pm

Even if said alternative diffusers were placed in the filter holder?

JimT
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Re: An alternative to Kohler?

#4 Post by JimT » Mon Jul 03, 2017 10:16 pm

What illumination does your scope have? On top of the lens or in the filter holder (you have one?). Try both and whichever one works best.

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wporter
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Re: An alternative to Kohler?

#5 Post by wporter » Mon Jul 03, 2017 10:57 pm

If your microscope has any sort of substage illumination source (besides a mirror!) built in, don't despair. You can fake up a field iris easily enough by cutting a small hole (1/8"-1/4") in a piece of black paper or cardstock, and laying that on top of the light well (the port the light comes out of). This simulates closing down a field iris. Then with the specimen in focus, raise your condenser until the hole edges are also in sharp focus. Your condenser is now set. Then remove the card & you're ready to observe.

apochronaut
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Re: An alternative to Kohler?

#6 Post by apochronaut » Mon Jul 03, 2017 11:05 pm

Just be aware that any diffusion of the light entering the condenser will lower the intensity of the illumination and lower the contrast somewhat.

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