38mm referrs to the focal length of the lens and has nothing to do with film size(except to alter the focal length for a specific effect). 35 mm is a perfectly usable focal length for medium-wide angle in a 35 mm camera. "Standard" focal length for a 35 mm camera is around 50 - 58 mm. Be aware that facial features tend to flatten out above 135 mm. I use 200 mm most of the time and it works for me. Jim