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Condenser adjustment for Köhler illumination
The image above shows condensers of various upright and inverted microscopes. This selection is not exhaustive and components may be located elsewhere on other models
- Condenser turret (Turret): Bright field position is H on Zeiss microscopes, A on Nikon microscopes and usually BF on Leica microscopes
- Field diaphragm adjustment (AFD): The DM2500 field diaphragm is on the other side of the stand. The Nikon Ti field diaphragm is near the top of the transmitted light pillar, labelled F
- Condenser focus (BFoc): This moves the condenser up and down but doesn't affect the focus of the specimen
- Centring screws (CCS): The Leica DM2500 and DMI6000 must be centred using hexagonal screwdrivers or Allen keys
- Iris aperture adjustment (DAP): The iris aperture on the DMI6000 is adjusted using the AP buttons on the left of the microscope stand
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- Focus on a transmitted light image of the specimen using a 10x air lens
- Rotate the condenser turret to the bright field position. This will be labelled H on Zeiss microscopes, A on Nikon microscopes and usually BF on Leica microscopes. Adjustment can either be manual or done through buttons or a touchpadtouch pad, depending on the microscope model
- Fully close the field diaphragm and adjust the condenser focus so the image of the iris is in sharp focus
- Centre the image of the iris using the two centring screws
- Open the field diaphragm until it is just outside the field of view
- Remove an eyepiece and look into the empty opening
- Adjust the iris aperture until it is about 70% open and then replace the eyepiece. The microscope is now adjusted for Köhler illumination
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