hand turns the microscope's fine focus adjustment knob

39aph39 adjustment analyzing arm biochemistry biology biotechnology camera chemical chemist chemistry closeup color development discovery dish doctor education electronics enlarge equipment examining experiment expertise eye fine focus furniture gadget glass hand horizontal hospital increase indoors iron knob laboratory lens lifestyles light lighting machine macrophotography magnification magnifying medical medicine microbiology microscope multimedia object petri piece professor reflection research room s science scientific scientist selective series sharpness side single small student technician technology tube turns used vehicle vertical view wheel