Filters for Olympus CX41 (phase, polarization and darkfield)

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Saul
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Re: Filters for Olympus CX41 (phase, polarization and darkfi

Post by Saul »

Dreamspy wrote:
Saul wrote:
Dreamspy wrote:I'm looking for ... darkfield as well...
Are they 28mm in diameter and 3mm thick ?
Not so sure... can I measure these lengths somewhere on the microscope?

If I understand correctly then darkfield is a mask you put on the light, right? In that case the diameter is much more than 28mm (of the light), and the thickness can be anything really, since there is a lot of empty space between the light and the collimator lens before the sample. Or am I misunderstanding something here?
I do not own Olympus microscope, should be something close to https://i.ytimg.com/vi/hVfViVn6eJ4/maxresdefault.jpg or similar

Some time ago I designed a set of the 28mmx3mm DF filters (for 3D printing) for one our forum member. Looks like I still have one set printed, and, if you are interested (& you are located in US), I can send it

Pau
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Post by Pau »

Dreamspy wrote:
Saul wrote:
Dreamspy wrote:I'm looking for ... darkfield as well...
Are they 28mm in diameter and 3mm thick ?
Not so sure... can I measure these lengths somewhere on the microscope?

If I understand correctly then darkfield is a mask you put on the light, right? In that case the diameter is much more than 28mm (of the light), and the thickness can be anything really, since there is a lot of empty space between the light and the collimator lens before the sample. Or am I misunderstanding something here?
Nope, the darkfield stop must be placed at the condenser as close as possible to the diaphragm. For different magnifications (actually NA) you need different stop diameters.
I don't know the particularities of your condenser. If it has an slot to place a phase ring this is the best position. If it has not that slot and the diaphragm is placed at the lower part of the condenser and it has a filter holder just under the condenser this is also a good place.

Phase contrast is more delicate: you need to get phase objectives and to put at the condenser matched phase rings for each objective. You need a condenser with a slot to place a phase ring at the right position or a dedicated phase condenser.

As beginner my advice is to calm down a bit. For example you can do decent pol work with cheap filters and then buy more expensive ones if you get hooked. Phase contrast if already you do not have phase objectives will be expensive while oblique illumination contrast is also excellent and can be done with little money if any.
For now I would concentrate in taking the best of your microscope with brightfield and also experimenting with dark field, oblique and pol (low cost way). Most of us can be equipment geeks but your technique with the microscope and sample preparation is often more important.
Pau

Dreamspy
Posts: 21
Joined: Fri Feb 08, 2019 4:49 pm

Post by Dreamspy »

Pau wrote:
Dreamspy wrote:
Saul wrote:
Dreamspy wrote:I'm looking for ... darkfield as well...
Are they 28mm in diameter and 3mm thick ?
Not so sure... can I measure these lengths somewhere on the microscope?

If I understand correctly then darkfield is a mask you put on the light, right? In that case the diameter is much more than 28mm (of the light), and the thickness can be anything really, since there is a lot of empty space between the light and the collimator lens before the sample. Or am I misunderstanding something here?
Nope, the darkfield stop must be placed at the condenser as close as possible to the diaphragm. For different magnifications (actually NA) you need different stop diameters.
I don't know the particularities of your condenser. If it has an slot to place a phase ring this is the best position. If it has not that slot and the diaphragm is placed at the lower part of the condenser and it has a filter holder just under the condenser this is also a good place.

Phase contrast is more delicate: you need to get phase objectives and to put at the condenser matched phase rings for each objective. You need a condenser with a slot to place a phase ring at the right position or a dedicated phase condenser.

As beginner my advice is to calm down a bit. For example you can do decent pol work with cheap filters and then buy more expensive ones if you get hooked. Phase contrast if already you do not have phase objectives will be expensive while oblique illumination contrast is also excellent and can be done with little money if any.
For now I would concentrate in taking the best of your microscope with brightfield and also experimenting with dark field, oblique and pol (low cost way). Most of us can be equipment geeks but your technique with the microscope and sample preparation is often more important.
Thank you for your advice, and your mostly correct. :)

Even though I'm highly interested in the topic, then what got me on this road is that I was hired by a local university to set up a nice microscope system, with the aim to show on open days at the university, to wow and stun possible future students. As well as shooting interesting pictures for their brochures.

So I'll be here for a limited time (even though I suspect I'll be sticking to this hobby for quite some time). They have a few thousand dollars to put into the project. I´m just trying to find out how to spend them most wisely without going overboard in DIY.

At the moment I'm very keen on buying the phase contrast, darkfield and polarization filters from https://www.optics-pro.com/microscopy/m ... /m,Olympus

Dreamspy
Posts: 21
Joined: Fri Feb 08, 2019 4:49 pm

Re: Filters for Olympus CX41 (phase, polarization and darkfi

Post by Dreamspy »

Saul wrote:
Dreamspy wrote:
Saul wrote:
Dreamspy wrote:I'm looking for ... darkfield as well...
Are they 28mm in diameter and 3mm thick ?
Not so sure... can I measure these lengths somewhere on the microscope?

If I understand correctly then darkfield is a mask you put on the light, right? In that case the diameter is much more than 28mm (of the light), and the thickness can be anything really, since there is a lot of empty space between the light and the collimator lens before the sample. Or am I misunderstanding something here?
I do not own Olympus microscope, should be something close to https://i.ytimg.com/vi/hVfViVn6eJ4/maxresdefault.jpg or similar

Some time ago I designed a set of the 28mmx3mm DF filters (for 3D printing) for one our forum member. Looks like I still have one set printed, and, if you are interested (& you are located in US), I can send it
Thank you for that, but I don´t think this´ll fit in my Oly. :)

Alan Wood
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Location: Near London, U.K.
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Post by Alan Wood »

I think the CX-PH1 is for 10x objective, CX-PH2 is for 40x and CX-PH3 is for 100x. I think they just push into the bottom of the CH3-CD brightfield condenser.

For phase contrast you need special objectives, your basic plan objectives will NOT work.

I think the CKX3-SLPIC is for an inverted microscope and not relevant to your microscope.

Alan Wood

Dreamspy
Posts: 21
Joined: Fri Feb 08, 2019 4:49 pm

Post by Dreamspy »

Alan Wood wrote:I think the CX-PH1 is for 10x objective, CX-PH2 is for 40x and CX-PH3 is for 100x. I think they just push into the bottom of the CH3-CD brightfield condenser.

For phase contrast you need special objectives, your basic plan objectives will NOT work.

I think the CKX3-SLPIC is for an inverted microscope and not relevant to your microscope.

Alan Wood
Thanks for clarifying that.

pbraub
Posts: 79
Joined: Fri Feb 02, 2018 1:23 pm

Post by pbraub »

Hi,

Alan Wood is correct. The CX-PH1,2,3 clicks into the CX condenser like the CX-AL (aux lens for centering, the condenser itself cannot be centered).

For darkfield and oblique (at least) one cheap option to try is to create a DIY stop out of black cardboard and put this below the condenser (or sandwich it between the AL and the condenser). (see page 5 here :
https://docplayer.net/16612495-Iso9001- ... glass.html)

I do not know how much presicion would be needed for a PH insert.

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