at present i use the rokinon 12/2 for my night shots and star trails (with my em5ii). i shoot wide open usually at iso800 . i deign to go higher (on iso) as i find the em5ii sensor a bit too noisy at that point. i can still capture the milky way with relatively good detail at those settings. however, i am toying with the idea of getting a 0.95 lens. thats full stops faster than the rok 12/2, theoretically it would allow me to drop 2 full stops of iso- which would put me at iso200. that would be a really clean image, if possible. i read somewhere (here) that the 0.95 voigtlanders produce ugly coma, so that kinda rules them out. what other options do i have for a focal length of 17.5 or wider, if any?