Condensers are located above the light source and under the sample in an upright microscope, and above the stage and below the light source in an inverted microscope. They act to gather light from the microscope's light source and concentrate it into a cone of light that illuminates the specimen. The aperture and angle of the light cone must be adjusted (via the size of the diaphragm) for each different objective lens with different numerical apertures.
Condensers typically consist of a variable-aperture diaphragm and one or more lenses. Light from the illumination source of the microscope passes through the diaphragm and is focused by the lens(es) onto the specimen. After passing through the specimen the light diverges into an inverted cone to fill the front lens of the objective.
Upright Microscopes
| Type | Technique | Numrical Aperture | Object distance(mm) | Magnification |
|---|---|---|---|---|
| Abbe condenser | Bright field | 1.25 | 4x-100x | |
| Abbe condenser | Bright Field | 0.9 | 1.9 | 4x-100x |
| Achromat condenser | Bright Field | 0.8 | 2.0 | 4x-100x |
| Achromat swing-out condenser | Bright Field | 0.9/0.22 | 1.8 | 2x-100x |
| Achromat swing-out condenser | Bright Field | 0.8/0.12 | 3.2 | 1x-100x |
| Sliding Achromat condenser | Bright Field | 0.9 | 2.2 | 2x-100x |
| Achromat/Aplanat condenser | Bright Field | 1.4 | 1.6 | 10x-100x |
| Long Working Distance condenser | Bright Field | 0.8/0.3 | 8.2 | 4x-100x |
| Long Working Distance Condenser | Bright Field | 0.65 | 10.2 | 4x-40x |
| Darkfield condenser (Dry) | Darkt Field | 0.8-0.95 | 4 | 20x-40x |
| Darkfield condenser (Oil) | Dark Field | 1.2-1.43 | 1.5 | 20x-100x |
| Phase condenser | Phase Contrast | 1.25 | 4x-100x | |
| Phase contrast condenser | Phase Contrast | 0.9 | 1.9 | 10x-100x |
| Universal Condenser (Dry) | 0.88 | 2.5 | 2x-100x | |
| Motorized Universal Condenser (Dry) | 0.88 | 2.5 | 2x-100x | |
| DIC condenser (Oil) | DIC | 1.4 | 1.6 | 10x-100x |
| Swing-out condenser | Polarizing | 0.9/0.22 | 1.8 | 2x-100x |
Inverted Microscopes
LENS attached additionally to condenser frame.
| Type | Numrical Aperture | Object distance(mm) | Magnification |
|---|---|---|---|
| Condenser lens | 0.72 | 13 | 10x-100x |
| LWD condenser lens | 0.52 | 30 | 4x-100x |
| ELWD condenser lens | 0.3 | 65/75 | 4x-40x |
| NAMC condenser lens | 0.4 | 44 | 10x-40x |
| High NA condenser lens (Dry) | 0.85 | 5 | 10x-100x |
| High NA condenser lens (Oil) | 1.34 | 1.95 | 10x-100x |
| Darkfield condenser (Dry) | 0.8-0.95 | 4.5 | |
| Darkfield condenser (Oil) | 1.2-1.43 | 1.5 |