I tried looking this up, and either it is so obvious I was missing it, or I was searching with the wrong key words. In particular I use a GF1. When I use adapted lenses is there a rule of thumb to determine the 35mm equiv. focal length? I know the standard lenses you multiply the focal lengthn by 2. What about when I use a standard 4/3 or 35mm lenses with an adapter? Thanks for your help in my pursuit of lens knowledge.