Hi Alex, the camera's Sharpness setting would be the first thing I would check. I've been fortunate to rarely have to deal with moire and aliasing issues on the 5D/7Ds, but I tend to keep the camera's sharpness pretty low. And in the times I have had an issue, usually reducing the sharpening by a level or two has made a difference. Another idea might be to try some light diffusion filters - SoftFX, Classic Softs, GlimmerGlass. I've personally never tried diffusion for this, but in a pinch, it'd be worth a shot. And then lastly, I might suggest taking advantage of the 5D's larger sensor and try to limit the focus as much as possible to your subject's face and thus avoid the problem jacket - obviously this is easier done in certain shot sizes and is also an aesthetic choice.