What do people usually load in the Extra slots of a Phase condensor?

[Gatorengineer64]

Another Noob question, My condensor has Ph1,2,3 BF DF and an A and B. Do people typically load different dark field masks polarizers or?

[PeteM]

Phase condensers often have only five positions (three phase annuli, brightfield and darkfield). Those with seven positions, apparently like yours, might have DIC prisms, an auxiliary lens for low power objectives, a quarter wave plate etc.

[farnsy]

My condenser has 4 phase contrast settings (10x, 20x, 40x, 100x). But then, it doesn't have a dark-field setting (sadly). I'm trying to figure out a way to get a dark-field annulus that works in my scope since I do have an empty position as well.

7 positions sounds like a lot. Perhaps it was meant to be a universal condenser, with DIC prisms in it as well. The polarizer usually isn't that useful in the condenser because it would be hard to rotate to get extinction--many/most analyzers don't rotate. Of course, if yours does, then that would be an awesome addition.

If you are looking for suggestions, you could probably fabricate an oblique illumination solution without a ton of trouble. The good thing about that is that it doesn't have to be perfectly centered...happy accidents! If you are good with crafting small things, then making a Rheinberg setting out of some photographic gels would be amazing. Probably going to take a few tries before you get it right. The basic dark blue center and red or yellow ring is a safe bet.

[MicroBob]

In some condensers the phase plates are painted on glass this sometimes doesn't last forever. Such a condenser would be nice to set up with one of the variations of oblique lighting.

[Hobbyst46]

My condenser has 4 phase contrast settings (10x, 20x, 40x, 100x). But then, it doesn't have a dark-field setting (sadly). I'm trying to figure out a way to get a dark-field annulus that works in my scope since I do have an empty position as well.

The phase 3 and/or phase 4 positions probably yield fair DF, at least with low NA objectives. Oiling the condenser to the slide (in positions phase3/phase4) might even make it better.

[Gatorengineer64]

The condenser I have is the Nikon Eclipse universal........ thanks for the ideas.

[BramHuntingNematodes]

You can get five or six lenses on a eclipse nosepiece can't you? Who knows but they may all need a different phase diaphragm.

[Scarodactyl]

At least 7, maybe even more on some more obscure nosepiece.