Different types of microscope use different type of illumination method. As far as Stereo Microscope is concerned, it uses the incident light illumination method. This type of illumination provides different visions to the left and right eye and thus it is possible to view a three dimensional vision. There are various uses of the microscope dissection, microsurgery, small circuit board manufacturing as well as inspection of various microorganisms.
One should not get confused with the stereo microscope and the compound microscope. Keep in mind that both of them are different. The compound microscope provides the Univision whereas the stereo variety provides the bin vision. Different eyes have different visions to see from different angles and thus the object can be seen from multiple angles, which is the basic concept behind the 3D vision. As far as the digital microscope is concerned, they come with the CCD camera. There is not much big difference between the optical microscope and the digital variety. Keep in mind that when the output is seen through the digital interface well connected with the eyepiece, the optical microscope becomes the digital version of the microscope. Generally, the CCD camera works as the digital interface.
The digital interface or the CCD camera has no effect on the magnification power of the microscope but a digital variety is highly rated as compared to the optical microscope. They might be used in various critical research and development processes. The technology has evolved and transformed the simple looking compound microscope into a newly looked and much powerful USB microscope, which are much powerful as compared to the optical microscope.
As far as the resolution is concerned, digitization has increased it a lot. There is no doubt at all that USB has been one of the very big inventions from Intel, much bigger than their other products like Intel core processors. Now, the microscope is being connected to the USB, which can then be connected with the computer, and rest of the story can be understood quite easily. Out of all the above the USB variety of microscopes are the most powerful variety and they are mostly used these days but for very critical use. They might be a bit costly when applied to high-resolution varieties of microscopes.