Compound Microscopes Vs. Stereo Microscopes
A Compound microscope is a high power microscope that is used for imaging smaller samples such as prepared slides, blood samples, water samples, etc. A compound microscope consists of objective lenses which rotate into position in order to give you the desired magnification. Standard objectives lenses range from 4x-100x magnification. The total magnification of a compound microscope is determined by the objective lens in place multiplied by the power of the eyepiece (standard is 10x)
For example: 4x Objective in place using a 10x eyepiece = 40x overall magnification.
Compound Microscope Choices:
In choosing a compound microscope you first need to decide if you require a monocular, binocular, or trinocular.
Monocular Microscope- A monocular microscope is a microscope consisting of a single eyepiece. For younger or inexperienced users this is ideal. The user will need to close one eye or train their eye to ignore the information it is receiving.
Binocular Microscope- A binocular microscope is a microscope consisting of two eyepieces. A binocular head offers more comfort to the user because you are using two eyes. All professional laboratory microscopes are binocular microscopes.
Trinocular Microscope- A trinocular microscope is a binocular microscope consisting of a third port to add a camera. You will require a c-mount in order to mate the camera to the head.
A stereo microscope is a low power binocular microscope used to look at three-dimensional objectives. 99% of stereo microscopes are binocular which provides a three-dimensional image of the specimen. A stereo microscope is used to look at insects, coins, bugs, rocks, gems, stamps, etc. The total magnification of a stereo microscope is determined by the magnification you have selected and the power of the eyepiece. If you choose an objective/auxiliary lens for your microscope you will add that into the magnification equation. Stereo microscopes can be highly configurable with numerous stands and illumination to choose from.
Stereo Microscope Choices:
There are two main choices, fixed magnification or zoom magnification.
Fixed Magnification- A fixed magnification stereo microscope allows the user to choose from two or three magnification options between 10x-40x.
Zoom Magnification- A zoom magnification stereo microscope allows the user to observe the specimen through a constant zoom or magnification range. For example 8x-35x.
Now that you have determined which microscope is right for your application you will need to decide on the microscope objectives. There are various types of objectives which help determine the image quality of the microscope you select. The difference in objectives is the extent of color correction and the flatness of field.
Achromatic Objectives- Also referred to as Achro or Achromat objectives. These lenses are ideal for students or hobbyists. Achromatic objectives are corrected so that the center 65% of the field of view is flat and focused, and are corrected for two colors.
Semi-Plan Objectives- Offer approximately 85% flat field.
Plan Objectives- Approximately 95% flat field.
Objective Correction for Optical Aberration
The most common microscope eyepiece is a 10x Wide Field (W.F.) eyepiece. Additional eyepieces (15x, 20x, &30x) are available to increase magnification.
Many online sites try and trick the customers by claiming magnification ranges of 2x-180x. They claim this because they offer multiple magnification eyepieces in order to gain the higher magnification. It should be noted that while using higher powered eyepieces you do increase magnification however you decrease resolution. This will result in a loss of detail and not a clear image.
Choosing the right supplier:
It is important to purchase a microscope from a well-established and trusted supplier. You want to be able to consult with the supplier and have them provide you with accurate information in order for you to make an informed decision. Buying from a company that not only sells microscopes buts that services them also is important. They know the microscope in and out and can make recommendations based on their experiences with the microscopes. Sure a microscope may look great on the outside however the internal mechanics and electronic components are important to take into consideration.
Choosing the right brand:
As with anything you purchase you expect the microscope to last and be supported even after the warranty period has expired. You should factor the brand into the consideration of your purchase. You should stick to a name brand microscope for the following reasons.
- Quality – The microscope factories in China copy the popular name brand microscopes. While they may look identical in a picture- they are not. They copies are made of plastic internally and externally. Some companies will use plastic in the optics as well.
- Support- A trusted established brand is here to stay. There are many brands that pop up and disappear leaving the customer with no support.
- Warranty- While some off brand microscopes claim their microscopes come with a warranty you will find that most never hold true to the warranty.
- Parts availability- Name brand microscope company’s stock parts to repair or upgrade your microscope long after the warranty period expires. If you want to upgrade or repair your off brand microscope you will most likely have to purchase a new microscope completely.