keep in mind, that you are actually looking for a .95 lens because the t3i has a horrible 1.6 crop factor! .95×1.6=1.52.
You can’t skimp on the ND filter or your picture will get very soft.
Also, cheap lens don’t have enough blades so the transition is harsh and
ugly. The more blades, the prettier the softness.
Unfortunately, coupling .95 with many blades, low chromatic aberration, ir coating, professional nd’s, will run you into the thousands. That’s the price you pay for cineramic quality.