Making own darkfield condensor from a photograpic lens?

[macrochemistry]

Hello!
Ever thought about making an own darkflied condensor by attaching an filter with a black spot in the middle on an for example old analog ~50m lens and putting the lens on an diffused light source?

The field could be adjusted by focusing the lens, by the size of the "black spot" on the filter ring and by the distance between the black spot and the lens.

Should'nt it work perfectly as darkfield condensor?


I tried it with an old defective M42 28mm F2.8 lens, but contrast was bad, as the lens had bad fungus, I used only reflecting aluminium foil as "black spot" and I can't find any good flat light source.

[g4lab]

What kind of specimen are you wanting to illuminate with darkfield?

You show a microscope objective. If you are using even an abbe condensor you can make a little disk to make it into dark field and it will work quite well.

If you are wanting to make it macro sized then start with an ER (ellipsoidal reflector) flood lamp and make it reflective rather than refractive. It is more efficient.

google stereo darkfield to see variants of what I am referring to.

[macrochemistry]

What kind of specimen are you wanting to illuminate with darkfield?

I want to do something like this:
http://photomacrography.net/forum/viewtopic.php?t=15761

You show a microscope objective. If you are using even an abbe condensor you can make a little disk to make it into dark field and it will work quite well.

If you are wanting to make it macro sized then start with an ER (ellipsoidal reflector) flood lamp and make it reflective rather than refractive. It is more efficient.

google stereo darkfield to see variants of what I am referring to

Thx, I will have a look

[g4lab]

What you need is a simple Abbe condensor with the top element removed and a darkfield obscuration disc.

What you propose with a 28mm camera lens very likely would work fine. But the abbe condensor should already be fitted to your microscope.