Levenhuk 3ST 20-40x Stereo Microscope

The 3ST is a binocular stereo microscope at 20x and 40x with halogen lamps above and below the stage, for looking at whole objects in three dimensions: minerals, coins and stamps, seeds and insects, or a circuit board. Levenhuk calls it the standard model of its stereo range and names biologists, geologists and jewellers as its users. The head is fixed at 45 degrees rather than rotating, and the 57 mm working distance between lens and stage leaves room for tweezers or a probe.

Two WF10x eyepieces sit in 30.5 mm tubes above a rotating objective that switches between 2x and 4x, and the tubes adjust from 55 to 75 mm apart with 5 dioptres of correction each way for a difference between your eyes. Rubber eyecups are included. Levenhuk says the optics are coated glass, and that the 3ST takes its own digital cameras, which fit in place of an eyepiece; our camera guide explains which to choose.

The stage is a 90 mm circle with clips and two plates: a matte glass one for the lower light and a reversible black and white one, so a pale shell goes on black and a dark beetle on white. Coarse focus travels 40 mm and the body is metal. The two halogen lamps run from the mains at 220 V, with no battery option, and Levenhuk puts a spare 12 V 10 W lamp in the box because halogen bulbs do eventually need replacing.

Also in the box are a dust cover and the manual. The 5ST above it swaps halogen for LEDs and has a 160 mm working distance, the 2ST below has no built-in light at all, and the rest of our stereo microscopes are listed together.