Originally posted by MadMathMind My mind instinctively translates "I don't shoot portraits with focal lengths below X" to "I don't understand how optics works. I don't want to learn that focal length itself plays a minor role in distortion."
That is why the person also mentioned working distance, subject separation, and other things; many of which I listed in my post earlier. I did not just say "herp derp focawl length is be all and end all!!"
Edit: One more thing, some say that the Pentax 50mm f1.7 genus is actually closer to 53mm, just labelled as 50mm because that is the standard. I'm not sure how true this theory is, just something that might explain why people see less of a difference between the Pentax 50mm and another brand's 55mm. Apparently focal length labels are not super accurate because they follow conventions. This is why we see so many 28mm lenses, but next to no 26mm, 27mm lenses, for example.