The Dino-Lite digital microscopes are designed to achieve the specified maximum magnification and clear focus with the scope either in contact with or on the same level as the observed object or surface, such as the skin, etc. The nozzle length is designed to provide the appropriate focal length to achieve this. When the scope is in this optimum position then the user will be able to achieve a clear focus in two distinct magnification ranges. In order to focus in the maximum magnification range simply continue to zoom beyond the first clear focus range on the observed object or surface until you see the object again come into focus. This second stage is the maximum magnification of the scope. When the scope is further away from the observed object or surface you will only be able to focus in at one magnification range.
General example how the Dino-Lite handheld digital microscopes optics works
The way the optics works with our scope is that there is one focus point in each distance. So farther you go the lower the magnification you can get. There is one exception at touching point where there are two focus points. One at around 50x and the other at around 200x. The device would get out of focus and into focus again from around 50x to 200x. To receive the magnification values in between, the focus point would be within the clear protective plastic lens.