The Image That Convinced Me to Anti-Alias

    As a Canon user, I watched cameras from Sony and Nikon outresolve my Canons by virtue of higher pixel count and lack of an anti-aliasing filter / optical low pass filter (OLPF).  I had assumed that Canon kept the OLPF around for their professional customer base but that I, as a landscape photographer, would not encounter the fine mesh patterns that the OLPF is needed for.  This sample image from Canon changed all that:

http://www.usa.canon.com/CUSA/assets/app/images/cameras/eos/EOS_5DS_R/sample_images/03.jpg

If we zoom into the reflections on the side of the hippo, there are severe color artifacts.

Crop from above.  Note the red, green, and blue color artifacts scattered in the reflections.

    The level of detail and sharpness that the AA less 50MP sensor provides is incredible, but the color artifacts render the image severely damaged.  A different demosaicing algorithm could potentially eliminate the artifacts, but not without significant loss of real detail as well.  The potential for color errors is not limited to man-made subjects, but can occur in images of any kind.

    It is worth noting the conditions in which color artifacts are most likely.  The subject must have high contrast details at a high spacial frequency and the optical system must be good enough to properly resolve those details.  Specifically, the lens must be perfectly in focus, at an aperture wide enough to limit diffraction, and sharp enough at said aperture.  The hippo shot was with a 500mm f/4 L IS II @ f/4 and so certainly meets those criteria.

   I am now grateful to be presented the choice of an OLPF and am asking myself "is the small increase in resolution worth the chance that a portfolio quality image would be ruined by aliasing or artifacts?"  Sadly for the pixel-peeper in me, I think not.