Camera makers load their goods with moiré-busting anti-aliasing (AA) filters, however these low-pass filters come with a big caveat. You see they are placed in front of the camera’s sensor and work by slightly blurring the image in order to avoid moiré and aliasing effects at the cost of resolution and sharpness.
It seems that Canon has chosen a pretty strong AA for its latest full-frame shooter, the 5D Mark III, which is bad news for videographers and lovers of sharp stills. Nikon offers two versions of the competing D800, the D800E flavor has a weaker anti-aliasing filter than the standard model, but Canon fans are pretty much stuck.
Now you’d think that a weak low-pass filter leaves you at the mercy of moiré, but in reality these patterns are not as common as they are made to be and we’ve seen the benefits to resolution of a weak anti-aliasing filter in our real world review of the Fujifilm X100 here.