Bresser Science TFM-301 40-1000x Trinocular Microscope

The Science TFM-301 is the trinocular version of Bresser's TFM-201, with the same semi-plan optics, Köhler illumination and single-hand stage, plus a third tube on top with a C-mount thread, so a MikroCam or any other C-mount microscope camera screws straight on with no adapter. That makes it the one for a lab or teaching room that wants to show a slide on a screen while two people still use the eyepieces.

The objectives are 4x, 10x, 40x and 100x oil, all semi-plan, which means the image is flat and sharp over most of the field rather than falling off towards the edges as it does with standard achromats. The pair of WF10x eyepieces give a 20 mm field, eye spacing adjusts from 55 to 75 mm and each eyepiece has its own dioptre ring, so two users can set it for their own eyes.

Lighting is a dimmable LED built into the base, arranged for Köhler illumination. In practice that means a luminous-field diaphragm in the base and an Abbe condenser underneath the stage, numerical aperture 1.25 with an iris diaphragm, that moves vertically to focus the light and horizontally to centre it. The magnifications printed on the condenser tell you where to set the iris for each objective. The stage and focus are driven by coaxial knobs on the same side, so one hand steers the slide and sharpens it.

Immersion oil, a dust cover, a mains adapter and the manual come with it. Our microscope camera guide explains C-mount cameras and what resolution suits a 1000x microscope. If you don't need the camera tube, the TFM-201 below it is otherwise the same, and the laboratory microscopes collection lists it alongside the TRM-301 and the Infinity.