Moving 30% further way sounds simple in principle, but aperture and depth of field is dependant on several factors, one of which is distance to subject. So say you set your camera to f8 and the subject is 1 metre away, if you then move to 1.35 metres from the subject, your depth of field is altered. Depth of field, being the distance, front to back that is in focus.

You can try it here: http://www.dofmaster.com/dofjs.html

Using a different lens, will give you an equivalent field of view, but other factors do come into play, again.

Why not just use what you have and experiment and learn from what happens. After all that is how we all learn about how to improve our photography, we try things, see what they do, and remember what does what, for future shoots. If we just copied what someone else does, all we end up doing is making copies, from instructions, and not really learning a lot along the way. Experiment, fail, experiment, succeed, is not a bad thing.