Drop in darkfield for the filter ring

[coominya]

Has anyone had any experience with these? The go in my filter ring below the condenser. Any reason not to buy them and experiment?



ebay link https://tinyurl.com/ybsfnqm6

There are other variants. Here is the full range

https://tinyurl.com/y9z6ez4u

[75RR]

Should work fine. They are similar in design to some homemade ones I made up by printing on transparencies that worked quite well.
These should in fact work a bit better. Less smudge!
You may need to vertically adjust the condenser a little to fine tune the darkfield stops.
Make sure your filter holder accepts 32mm filters

[MicroBob]

You might first try with a homemade one (coin, washer, aluminium foil circle on slide, overhead projector plastic sheet...)
Not all condensers work similarly well with dark field stops in the filter holder.

[zzffnn]

You may draw circles on glass slide using precision circle templates. Then precisely fill those drawn circles with craft putty and precisely remove excess with knife. Protect finished putty stops with transparent tape.

Use putty to attach said slides to conden bottom, using the other side of the slide.

[coominya]

Should work fine...
You may need to vertically adjust the condenser a little to fine tune the darkfield stops.
Make sure your filter holder accepts 32mm filters

yes it's 32mm at the top, 30 at the bottom, I checked it with the digital vernier.

You might first try with a homemade one...
Not all condensers work similarly well with dark field stops in the filter holder.

Good point. I'll rough something up for a test first.

You may draw circles on glass slide using precision circle templates. Then precisely fill those drawn circles with craft putty

I have said template, and plenty of blutac, that should do.

[desertrat]

I hope this isn't misinformation, and someone please correct me if it is. My memory isn't the greatest anymore. In a microscopy book published around 1900, and I'm not sure which one it was, it was recommended to place dark field and oblique illumination stops as close to the condenser iris diaphragm as possible.

In many modern Abbe condensers, the filter holder is quite a distance below the diaphragm. If your condenser allows you to remove the block containing the lenses, you might be able to drop in the stops right on top of the iris. This is what I do with my A/O Abbe condensers, even though some of them have filter holders at the bottom of the condenser bodies.