Может не всем это интересно, но мне, как программеру было очень интересно# F90X will not fire shutter with open back unless it is set for Manual mode and shutter speed of 1/250. However it can be reprogrammed to ignore open back sensor and fire as if back would be closed.
# There is an internal limit for number of frames on a single roll of film. F90X will not make more then 99 shots on one film roll. That sets the limit for bulck loaded back if somebody makes one.