The 420AHF-15 1-4x Stereo Zoom Microscope from National Optical is a stereoscopic zoom microscope designed for laboratories and university students. The stereo (two) eyepiece configuration is preferred by most researchers and students because of the superior depth of field and comfort compared to monocular microscopes. The 420AHF stereo microscope has a paired 15x eyepiece delivering a 15x to 60x continuous magnification range. The achromatic objective lens system is parfocalled and parcentered throughout the zoom range to keep the specimen in focus and centered while zooming in/out.

The 420AHF can illuminate the specimen from above using a 15W halogen light and/or from below the stage using a 5W fluorescent light; each light source is activated separately by base-mounted On/Off switches. To help optimize the brightness and contrast of the specimen, the top (incidental) light beam is intensity and direction adjustable.

A user-friendly design complements the range of features that make the 420AHF stereo zoom microscope a welcome addition to labs and classrooms. The viewing head accommodates specimen heights up to 45mm / 1.8" and is capable of 360° rotation to help share the stereo eyepiece among colleagues and students without moving the microscope. The rack and pinion system has dual focus dials and includes a slip clutch mechanism to prevent mishandling. An adjustable interpupillary distance, individually adjustable diopter correction, and reticle holder/retainer provide the 420 series with the flexibility needed to create a customized viewing experience.