The silicone rubber parts is used for the protector of high-class lens,
the reason is to apply the property like their impact absorption nature and non-corrosiveness.
It is also the feature that a lens standard and manufacture name can be printed on a slope.
Although a right side photograph is the shutter release of a compact camera,
the two-step action (focus and taking a picture) is to apply the strong point of
a silicone rubber switch, and it is our know-how that is it get the feeling of the responsive touch.