Hello,
I made a shader in which a ramp controls opacity of a nurbs sphere (for an eye). There is an issue with rendering - there is a white sort of noise - not entirely smooth transition as the ramp would suggest. Do I need to blur or convert ramp output somewhere? Attached you will find necessary screens. Thank you in advance!

Might be caused by the Stochastic Transparency set up in the Mantra ROP.
First try turning off Stochastic Transparency.

If you need to have it on (rendering volumes or hair), then try increasing the number of opacity samples.

Thank you. Increasing samples helped. Turning off stochastic transparency made the object completely opaque.
Thank you again!