Hi,

Using a 100/1.25 with a 1.2-1.4 darkfield condenser will give you COL (circular
oblique lighting) which is in itself a very impressive illumination technique.
If you just want to have darkfield at higher magnification then the investment
in a high NA dry or water immersion objective is worthwile. What about a normal
60/0.85 objective, that's nearly in the magnification range that you want. For
what do you need the 1000x darkfield?

Rolf


--- In Microscope@yahoogroups.com, "grimra" <ralphg@...> wrote:
>
> Hi all,
>
> I am using darkfield illumination for most of my microscope work. It's so
beautiful with the jet-black background and microorganisms looking like Chinese
lamps floating through the night.
> I have a question though: I want to use higher magnification of say, 700-1000x
using an oil immersion objective such as an 100x Olympus Planachromat with an NA
of 1.25 for a BX50 microscope. I am using a cardioid oil darkfield condenser
with an NA of 1.40. Can I use this objective with the condenser as it is, or do
I have to use a stop of some sort for such an objective?
> Thank so much.
>
> Regards,
>
> Ralph
>