In general any Pentax lens will work on a new body with the abilities it had on the older body. If it was auto-focus then it will auto-focus on new bodies. Here is a link on
using older lenses on new cameras, most of this is for lenses even older than yours but it might be interesting.
Also, just FYI but Pentax 28-70 can be an enormous number of different lenses with different abilities. You need to specify the series (F, FA, DA, DA*) and the aperture (f/2.8, f/4, f/4.5-5.6) in order to get good information back. There is an extensive lens database here on the forum with listings for just about every Pentax lens ever made and it includes info on compatibility and relative quality of the lens.
I believe the SF7 used F series lenses, if that is what you have it will work just fine. I have a number of F series lenses that I use on my k-5.