Quote Originally Posted by Dr Croubie View Post
I'm also confused at it covering 6x6. 50mm on 6x6 is pretty wide. Maybe the sign meant to say "was based on", ie a 50mm 'normal' planar based on an 80mm 'normal' planar.
I would think that, being as the lens was made exclusively for NASA, the specs would be a bit different than for open market stuff. NASA might well have been fine with vignetting as long as it was a fast enough lens for whatever the target mission was.