episcopic adapter

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soldevilla
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episcopic adapter

Post by soldevilla »

I have no experience in this. I want to do some photography tests using incident light, that is, a beam splitter that sends the light through the optics of the microscope objective, and that light reflected from the object goes back through the beam splitter to go to the camera. I am writing this because I have seen lenses that have a conduit for light around the lenses like a small ring illuminator, and that does not work for me.

Is there a module that can be attached to a modular system like the ones we use? that is, not a complete microscope, but an objective, some extension tubes and the camera, all organized on a guide support with a stepper motor.

And one last question. Isn't this system extremely sensitive to loss of contrast and reflections in the image?

Thank you

Pau
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Re: episcopic adapter

Post by Pau »

Beginning from the end,
And one last question. Isn't this system extremely sensitive to loss of contrast and reflections in the image?
Yes, it is, due to reflections both on the subject surface and on the objective lens elements.
In many cases this kind of systems use crossed polarizers, a polarizer between the light source and the beamsplitter and an analizer between the BS and the sensor.
To avoid objective internal reflections often you can see a rotatable 1/4 wave plate between the objective and the sample ("antiflex" in Zeiss naming)

Likely Thorlabs and similar Optics big names could have the kind of device you want, although I guess much less expensive adapting a microscope epiiluminator for the task (even more when mastering 3D printing :D )
Pau

soldevilla
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Location: Barcelona, more or less

Re: episcopic adapter

Post by soldevilla »

Oh! Thanks, Pau. I go to try find something in internet...

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Scarodactyl
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Re: episcopic adapter

Post by Scarodactyl »

It does seem that the quarter wave plate under the objective is only needed at lower magnifications. It's essential for stereos and macroscopes, and strongly recommended for the mitutoyo 2x objective (the 1x I think they suggest a whole polarizer?) But 5x and up it isn't really an issue. Maybe that's more a factor in modern objective design generally.

Lou Jost
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Re: episcopic adapter

Post by Lou Jost »

The very cheapest way to do this is to buy an epi-illuminator and integrate this into the space bertween the objective and sensor (or tube lens). This can cost as little as $35 (one now available at that price on eBay). I also bought a second, cheaper, simpler epi-illuminator for the same microscope (Nikon Optiphot), which I cannibalized for its connectors. One of these connectors can be modified to hold a microscope objective adapter, and the other can be modified to take a camera or tube lens. You don't actually need the micrscope for this; in fact, it works better without a microscope. I have a vertical system and this illuminator sits on it directly.

This can also be used for a "poor man's fluorescence" adapter, with the addition of some filters. A dichroic mirror is not needed if your UV light source is strong enough.

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Scarodactyl
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Re: episcopic adapter

Post by Scarodactyl »

Make sure when getting a Nikon one that you check that it has both a polarizer and an analyzer before you buy. Some of them don't have a separate polarizer slot so I assume a polarizer is more permanently installed, but these are often stripped out. The rotatable polarizer with a slot for a quarter wave plate tends to be much rarer and more expensive since you can use it for epi DIC, but if you can get it or DIY it it's worthwhile to have that extra degree of control.

Chris S.
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Re: episcopic adapter

Post by Chris S. »

I started on a similar project last winter, using an Edmund Optics plate beam splitter and mounting cube. Integration should be pretty easy, but I got sidetracked onto other projects and the parts still wait on my work table.

--Chris S.

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