Hi there... Am expanding my collection - currently have the Helios 58/2, Takumar 105/2.8 & the Panny 20/1.7 on my GF1. I read a lot about the nifty fiftys but recognize that's on a full frame sensor. If I wanted to achieve the same optical distance on the GF1, I'd need to get 25mm lens correct? Was pondering if I should pick up a Zuiko 28/2.8 or possibly a 24mm lens. Any thoughts?