MAGUS HCM360 Device for working with the Hoffman modulation contrast with objective set

The MAGUS HCM360 device consists of a set of plan achromatic objectives a condenser and a slider that are designed for Hoffman modulation contrast microscopy. The objective modulator is aligned with the slit apertures of the slider using a centering telescope from the microscope kit.

The Hoffman modulation contrast technique produces high-resolution relief images of live objects. It provides good visibility and contrast of the samples with high-resolution details and without diffraction halos allowing the use of long working distances and high numerical apertures.
The technique does not degrade the image quality when both glass and plastic laboratory dishes are used and therefore it is widely applied for the observations and photo recording of cultures cells and tissues grown in containers Petri dishes and vessels.
One of the most common applications of the Hoffman modulation contrast is in vitro fertilization (IVF). The technique allows the real-time study of dynamic processes and helps to obtain valuable information about the behavior and interaction of cells.

Objective set

Hoffman objectives differ from standard objectives by having an amplitude spatial filter (modulator) in the back focal plane. The modulator has three zones: The first one transmits 1% of the light (dark zone) the second – 15% (gray zone) and the third – 100% (transparent zone). The ring on the Hoffman objective is used to rotate the modulator and place it in the operating position.

Unlike the phase ring in a phase objective the modulator in a Hoffman objective does not change the phase of the light but it only affects the intensity of the light. The modulator produces an image with a pseudo-relief effect.

Hoffman plan achromatic objectives form an image that has the same focus in the center and at the edges and therefore the distortion is negligible. Chromatic aberrations are corrected for blue and red spherical aberration for green and the field curvature is corrected for 90% of the field of view diameter. The objectives may be used for working with dishes with a bottom thickness of 1.2mm and they are designed for the infinity-corrected tube length. The parfocal distance is 60mm.

Hoffman condenser

The Hoffman condenser is installed in place of the regular brightfield condenser. It has a slot for the Hoffman modulation contrast slider an aperture diaphragm and a polarizer to control the slit opening. The polarizer is 360° rotatable. It is rotated by the rotating ring located above the aperture opening control.

Hoffman slider

The Hoffman slider is inserted in the slot of the Hoffman condenser. The slider is a plate with three round inserts for 10x 20x and 40x objectives. The marking of the insert matches the objective being used. There are two slots in each insert: one is free and the other one is closed by a polarizer. The inserts in the slider are 360° rotatable and centerable.

Adjusting the microscope to enable the Hoffman modulation contrast technique:

1. The Hoffman condenser and objectives are installed on the microscope.
2. The objective in the optical path is focused on the specimen in the bright field.
3. The Hoffman slider is inserted in the condenser slot and the insert is selected based on the objective magnification. The condenser aperture must be fully open.
4. One of the eyepieces is removed from the microscope head and replaced with a centering telescope from the microscope kit. The telescope is used to align the objective modulator with the slits of the slider. The modulator zones and slits shall be parallel to each other when one of the slits is fully projected to the gray zone and the other one to the transparent zone. If the ring movement is not sufficient to install the modulator in the desired position remove the slider from the condenser rotate the insert with a slit install the slider back in the slot and then readjust.
5. By rotating the condenser a slit aperture in the transparent zone is blocked: One can be completely or partially closed or completely open.
6. The Hoffman slider should be removed from the condenser to get back to the brightfield technique. It is not necessary to remove the objectives and condenser as they are suitable for brightfield observations. However to obtain the best image quality in the bright field we recommend using MAGUS 10PL60V 20PL60V and 40PL60V objectives and a standard condenser from the microscope kit.

Compatibility:

• MAGUS Bio V360 Biological Inverted Microscope

Package:

• MAGUS Hoffman condenser NA 0.5 WD 45mm
• Infinity plan achromatic Hoffman objective: 10x/0.25 ∞/1.2 parfocal distance: 60mm
• Infinity plan achromatic Hoffman objective: 20x/0.40 ∞/1.2 parfocal distance: 60mm
• Infinity plan achromatic Hoffman objective: 40x/0.60 ∞/1.2 parfocal distance: 60mm
• Hoffman slider for 10x 20x and 40x objectives