It should be kept in mind by all that the Biogon 38mm on the Hassy SWC was designed back in a day when retrofocus lenses indeed had design limitations in portrayal of rectilinear features without considerable barrel distortion, while the first version 40mm Distagon for the SLR exibitied distortion quite considerably. Later Hasselblad updated with a newer 40mm Distagon, which was a notably sharper lens than the older Biogon and which also greatly reduced lens abberations in spite of its retrofocus design.
Originally Posted by Ian Grant
Similarly, it used to be that zoom lenses were considerably inferior to fixed FL lenses, back when computers were not used for lens design. Today's zoom lenses often rival and even exceed the performance of even fixed FL lenses which have not been updated in the optical formula with newer computerized designs.
In short, what used to be true is not always still true today!