Iris diaphragms from the standard programme S (with snapring)

Entirely of metal, blades of spring steel, screwed in lever.

N = Blades of burnished spring steel

temperature stability up to approx 250° Celsius

AR = Blades with antireflex coating

temperature stabilty up to approx 180° Celsius

H = Blades of stainless spring steel

temperature stability up to approx 400° Celsius