Swift FM-31 LWD

is a portable "field" microscope designed for a variety of field work. Basically, it allows the user to observe the specimen in a light field, which can be extended with the addition of specific methods such as dark field, phase contrast and qualitative polarization.

The basic optical equipment of the FieldMaster FM-31 microscope consists of LWD achromatic objectives with magnifications of 4, 10 and 40×, which can be supplemented with LWD 20×. The eyepieces offer a wide field of view and come with 10 and 15× magnification.

With its practical leather case measuring 154 × 52 × 114 mm and weighing 1056 g, it allows for easy and safe transport.

There were two variants of microscopes and the lenses supplied with them:

LWD achromatic lenses: (FM-31 LWD) a newer series allowing observation of specimens e.g. through a petri dish

Standard achromatic objectives: (FM-31) original edition with standard working distance objectives. At higher magnifications, only permanent slides could be observed, as they could not sharpen a wide base

The first microscope was made in the 1980s. Until the 1990s, the FM-31 was produced with a central horizontal focusing system, which was not very reliable, so an improved model with a ring focusing system was introduced, which did not suffer from the previous shortcomings and allowed smoother and more comfortable focusing.

Unfortunately, the actual microscope does not have the original light source in the form of a Mini Mag-Lite flashlight and support arm. For this reason, a custom solution had to be designed that also allows for infinite brightness control and the choice of different colour filters. The entire light source is 3D printed on a 3D printer and includes a powerful LED from CREE, a 3300 mAh Li-Ion battery and easy charging via USB port. Of course, the light does not lack an optical assembly consisting of calculated lenses positioned so that the light achieves Köhler illumination at all magnifications.