Some Pentax film bodies will allow you to adjust the aperature from the camera body. I bought a MZ7 and two lenses just for the ability to use some of our DA lenses on film as well as digital. I would guess that this lens will not cover FF below about 22mm based on my wife's 16-45 4.0 which starts at 21mm. Your lens is only the kit lens so not much resale value anyways so play around