It must be super dark in that area without the strikes, because at that mid aperture and the ISO, exposures of 30+ secs usually bring in a reasonable amount of light if there is any ambient around. I use either the 17-35/2.8 or the 50/1.4 and an f/stop of between f/8-13 with shutter speed according to ambient as a guide (meter it first before going to manual mode).