>>3342454It will still be 50mm, as focal length is a physical property of the lens. However, due to digital cameras having different-sized sensors, a "35mm equivalent focal length" is often calculated to give a common denominator - a focal length of a lens giving the same field of view on a 35mm film camera.
Your OM Zuiko 50/1.8 will give a narrower field of view on your E-M10 than when mounted on its native OM film camera (equivalent to a 50*2=100mm OM lens on OM camera).
