Leica M125 B Manuel D’Utilisation

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Leica M series 
User Manual 
38
The iris diaphragm in the optics carrier of your 
M series microscope has the same purpose as 
those in a camera shutter: it regulates the avail-
able light, which changes the depth of field. The 
"depth of field" (or "depth of focus") is the area 
of a specimen that is brought into sharp focus.
Closing the iris diaphragm
 
Close the iris diaphragm by turning the 
knob to the left. The subject appears darker 
and the depth of field increases.
Opening the Iris Diaphragm
 
Open the iris diaphragm by turning the 
knob to the right. The subject now appears 
brighter, but the depth of field decreases.
Iris Diaphragm