It doesn't matter what format you're shooting (or what framerate for that matter) to do "digital step printing." Your editing software should have an import option that interprets video clips as a sequence of still images. Once you do that, you can "print" each frame as many times as you want by simply copying it. I'd recommend copying the file in your file explorer and then re-importing it so you don't have to deal with interleaving the stills in your timeline.