« on: July 13, 2013, 12:24:32 AM »
The 50mm 1.4 is a old lens (1993) designed for film, so the effects of light drop off at the edge of a digital sensor are not compensated for. Newer lenses do a better job of collimating the light so it comes in at a steeper angle, and the effect is less.
I don't think it's possible to collimate the light and still end up with a sharp image. There's urban-legend BS at work in that link.