Cameras and microscopes
Two more instruments put a convex lens to work.
The camera
A camera uses a convex lens to form a real image on its film or sensor. Moving the lens changes its distance from the film, so a sharp image of objects at different distances can be focused on it.
The compound microscope
To see things too small for the naked eye, a compound microscope uses two lenses, the objective and the eyepiece. Together they give a very large magnification.
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