You can have some lighting issues between the microscope and camera. A ring light is really close to the lens, reflects directly back up, and the image can be ok in the eyepiece, but bad on the camera. Polarizing filters help, or if you're really adventurous, you can do what SteveyG did (the tl;dr of that is fewer, higher wattage lights, mounted further off axis, at more acute angles). A ring light will be fine to start with, but you're most likely going to look for a different lighting solution in the future.