For the Greenough system, the primary advantage is that it provides a pronounced three dimensional image and is very useful for relatively low magnification and inspection of items with "depth". Because of the "V" design of the optical path (b), as magnification is increased, both by the use of auxiliary lenses and higher magnification eyepieces, there is a divergence of the point on the subject where each optical path is focused and resolution appears to degrade. This is what limits the effective magnification range of this design to approximately 125x.
|(a) CMO optical design (b) Greenough optical design|
The images below were captured from the left and right eyetubes on a Greenough stereo microscope. As you can see, the crossline in the left image is offset to the left, and the crossline in the right image is offset to the right. Everything is exactly the same for these two images except for the moving camera from the left to the right eyetube. Specifically, this is exactly what a Greenough system should look like, because this is how the microscope system generates a three dimensional type of image.
|Greenough Stereo Microscope image from left eyetube and right eyetube.|
If you have questions about which stereo microscope system will best meet your needs please contact Microscope World.