Leica DM IRB manual Setting phase contrast with condensers 0.53 S23 and 0.90 S1

Setting phase contrast with condensers 0.53 S23 and 0.90 S1

Phase contrast observation is possible with condenser 0.53 S23 with objective magnifica- tions from 5x to 100x, with condenser 0.90 S1 from 10x to 100x.

For both condensers, phase contrast is set as described as for the 0.30 S70 condenser. However, before the centration process itself, correct Koehler illumination must be set.

Possible errors

Specimen: too thick, too thin, staining too intense; refractive index of mounting medium and specimen identical, so there is no phase jump.

Specimen slide too thick, so Koehler illumination not possible.

Wedge-shaped coverglass position, so centra- tion of light and phase ring is no longer effective.

Wrong light ring, or light ring has been put in the disc upside down.

Aperture diaphragm not open.

Light ring not centred.

Wrong light ring.

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