Hello there, I am looking for my next lens. I really love my Pana 20mm f1.7 lens, however, its autofocus is just too slow for low light conditions such as photographing rock shows. I love the field of view on the 20mm, though I am open to something a bit wider or a bit narrower. I have tried the PanaLeica 15mm f1.7 via BorrowLenses, and was quite pleased with its performance, especially the super speedy autofocus. The only thing I really did not like was that the hardware aperture ring did not work on my Olympus OM-D EM-1 (I know that this is the case with all Olympus bodies). If I am going to spend ~500 on a lens, I want ALL of its features to work well with the EM-1. My budget is right around $500. I'd love suggestions on a fast prime in the 17-50mm range which works well with the EM-1. I am considering the PanaLeica 25mm f1.4, as they can be had second hand for reasonably cheap. Opinions?