The most standard microscope is the Compound microscope. These are used to observe specimens on microscope slides under high magnification, using either transmitted or reflected light. Stereo microscopes are used for viewing larger objects in 3D, such as fungi, fossils, crystals, insects or micro-dissection. The magnification range is lower than the compound microscope, eg. 10x to 50x. Skip to step 5 if you require a Stereo microscope.
Decide if you require a 100x objective
If you need high magnification e.g. to view bacteria, detailed organelle structure, you will need a 100x objective lens. Most 100x objective lenses are designed for oil immersion and must have an abbe condenser and iris diaphragm to focus the light source onto the specimen.
Select the type of illumination you need
You have the choice of using a mirror to gather light (from a window or microscope lamp) or using built-in illumination. A mirror will suffice for low magnifications (100x) but for higher magnifications (400x) either a built-in source or lamp is required. There are three light types:
Tungsten: which is the most common and least expensive. The glass envelope around the bulb darkens with age due to vaporization of the filament.
Fluorescent: a cooler bulb, which is best for viewing live specimens. The bulb is long-lasting and gives an even illumination but is not as bright as tungsten.
Halogen: found on high specification microscopes. Halogen illumination is white and extremely bright and is ideally suited to high power microscopy (1000x)Finally, the light source should be focused on the specimen. At low magnification, the concave mirror focuses the light onto the stage. At higher magnification, a condenser is required.
Select either monocular, binocular or a teaching head
Binocular heads offer greater comfort and less eyestrain. Choose a binocular for project work or if the viewing period is to be of long duration. Monocular heads are available as vertical or inclined heads. Vertical is better if the user is standing and natural light is used as the illumination source. Inclined heads are more comfortable if seated.
Select stereo microscope features
The first choice to make is the range of magnification. Single magnification is found in the junior stereo microscopes. Dual magnification is offered on the WLMST05 and the WLSZ08 stereomicroscopes. The WLMST05, WLSZ08 and the WLZ6000 offer both transmitted and incident illumination. Other options include upright or inclined viewing and body size.