BUYING A MICROSCOPE
Microscopes
If you are looking for a student or hobbyist microscope, you will have many questions about finding the most suitable microscope.The optics, illumination, resolution and optional components are all important in finding the best microscope.
You'll also want a microscope of sturdy construction - to endure years of use. The best microscopes are made of metallic alloys that reduce vibration and still produce a good image with temperature variations. Never buy a microscope with plastic parts.
Microscope Optics
The lenses are the most important component in a microscope. However, without a good system for focusing, good optics will be of little use. It’s also prudent to buy a microscope with lenses compliant with international DIN standards, enabling you to replace lenses more easily should one become damaged.
Microscope lenses should be color-corrected to ensure you see everything you are viewing. Look for "achromatic lenses". This lens type will be acceptable for most amateur and student applications.
The microscope eyepiece, known as the ocular, should be of the "wide field" type. This is easier to use and usually houses a 18mm lens, a good size for viewing by everyone including children.
Monocular and Binocular Microscopes
If you will be using your microscope constantly, a binocular microscope (with twin eyepieces) will be more comfortable. Most professional microscopes are binocular. But if the microscope is for use by a child, a monocular (one eyepiece) microscope might be more suitable, since children can have difficulty with the eye accommodations necessary for binocular microscopes.
Several different lighting systems are avalable for the modern microscope, tungsten being the most common and cheapest. It provides a steady source of light but with some disadvantages. Its light is yellowish, affecting color accuracy, and generates a lot of heat, drying out specimens and even killing some living organisms.
Fluorescent microscope lighting is more expensive, but has several advantages. Its light appears whiter and more natural, and it generates much less heat.
Halogen lighting is used in medical and research microscopes. This provides a very bright, white light. Halogen is the optimum choice for binocular microscopes.