Canon 40mm f/2.8 STM on Canon 5DS R: What Can a Pedestrian Lens do at 50 Megapixels?
Get Canon 5DS R and Zeiss Otus and Zeiss ZE SLR lens B&H Photo.
The Canon 5DS R has no anti-aliasing filter, which has two effects: (a) an increased propensity to moiré and color aliasing, and (b) superior micro contrast (visible and commented upon in some of the comparisons).
Comparing control of moiré between the Canon 5DS R and 5DS:
Moiré and Diffraction Across Apertures: Canon 5DS R vs 5DS (Window Screen)
The results are of practical value for anyone considering which model to acquire as well as a practical approach to combatting moiré.