Bresser Science TFM-201 40-1000x Binocular Microscope

The Science TFM-201 is a binocular laboratory microscope with semi-plan objectives, Köhler illumination and a single-hand mechanical stage, for a school or college lab, a vet or a clinic that works at 40x to 1000x all day. Bresser lists it for laboratory and research use as well as education.

Semi-plan objectives are corrected for field flatness further out than standard achromats, so a stained section stays sharp across most of the view rather than only in the centre; the four are 4x, 10x, 40x and 100x oil. The WF10x eyepieces show a 20 mm field, which is wide for 10x, in 30 mm tubes, with dioptre adjustment on both and eye spacing from 55 to 75 mm.

Köhler illumination means the lamp, a field diaphragm and the condenser are set so the light is even across the field and the lamp itself is out of focus and invisible. The TFM-201 has the luminous-field diaphragm built into the base and an Abbe condenser (numerical aperture 1.25, with an iris diaphragm) that adjusts both up and down and side to side, so it can be centred. The condenser carries a printed scale of magnifications, so you turn the iris to the mark for the objective in use rather than guessing. The LED is dimmable and built in.

Coaxial knobs drive the stage and the focus, so the slide and the sharpness are both controlled from one hand without reaching across. In the box are the microscope, the four objectives, both eyepieces, immersion oil, a mains adapter, a dust cover and the manual. For 1000x with oil at a lower cost, the Bresser Researcher 40-1000x below it has achromatic objectives and no Köhler; the TFM-301 adds a camera tube to this same stand. Our how to use a microscope guide walks through condenser and iris settings for a first slide, and the other laboratory microscopes are listed together.