Oly E-M5: What % of pic do you see in viewfinder & using legacy lenses

Concerning the OLY OM-D-E-M5, I cannot find any specifics concerning what percentage of the final picture you actually "see" in the viewfinder. I currently have an E-510 which crops a lot of the final pic, and not evenly as between sides and top.
Also, can you use "legacy" lenses (from my old Olympus OM-1 SLR) with the E-M5? I have several which I use w/adapter on my E-510.  Thanks for any help/comments.