A couple of weeks ago I tried some Iford Pan F in my 1970s Diana. It was a bright sunny day in Sydney and working on the Sunny 16 principle I hoped to get decent results with the Diana aperture range of around f/11 to f/19. First roll was processed in Xtol 1:1 at the standard MDC time and was about 2 stops under exposed. I processed the remaining rolls with a 2 stop push. Xtol 1:2 for 15 minutes at 20.5 deg C. This was late afternoon at Martin Place. I now operate on the assumption that the Diana shutter speed is 1/200.