(it doesn't auto-correct for distortion since Lightroom has no way of knowing what lens you are using, but the profile is available for RAW files)

Canon 5D Mark 2) and download the appropriate RAW profile.

Lens distortion can be easily corrected in Light room and Photoshop by installing the appropriate lens profile for the Samyang.

To add on this, the moustache distortion is very severe, and I have not been able to find a good lens correction profile for Lightroom for this lens.

I think this is remedied pretty easily in LR or other editors with the proper profiles

The mechanics of the entire lens really gives the impression of quality just as much as the more expensive L lenses but in a plastic body of course.