Summary
This particular stereo microscope is sold under several different brand names. The model of the microscope is “SZM” and when you search Google for it, then you will find it under a variety of different combinations. It is one of the few stereo microscopes with a zoom objective (0.7x to 4.5x). With the provided 10x eyepieces, the microscope magnifies from 7 to 45 times. It is also possible to connect Barlow lenses to the objective to either increase or decrease the maximum magnification. A decrease of magnification increases the working distance and depth of field.
The model that I bought did not come with a lamp and I therefore connected a separate ring-light to the microscope. In order to connect it, I also had to buy an additional adapter.
The microscope head has a lever, which allows for the redirection of light to the phototube. The light will either go out the left eyepiece or the phototube, depending on the setting of the lever.
Advice
If you have the model with the phototube, then you can adjust parfocality. To to the maximum zoom level and adjust the length of the phototube in such a way that it is parfocal with the eyepieces. Now if will also be parfocal at other zoom levels.
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