I second neuro's recommendation, the 35L.


I have a few dark restaurants I go to. One is real dark and I have never gotten decent pics there with the 35mm 1.4L. I can never get enough speed even at F1.4 and a higher ISO. Never over 3200. I keep trying though.


Even though you gain a few F stops and loose some depth of field with the 35mm, you still may not end up with the IQ your looking for if it is real dark.


From what you are describing 2 stops might not be enough gain for ambient only.