You'll bump into the 1/2000 shutter speed limitation. If it's sunny, they'll be completely useless. You may succeed in using the 50/2.8 in shadow areas, for creating portraits with bokeh, etc.
Or use ND (Neutral Density) filter, i have a nice round plate set with UV, ND 2x, ND4x with 30,5mm thread, perhaps you might not use them with addition for avoiding vignetting (as the original sunshade too).
If you already own ND filters with a larger thread try to find an adapter 30,5mm to XXmm.