a_f12

I've taken on snapping photos as a hobby and bought myself a Canon Rebel SL1 to play with. Recently my close friend asked me if I would take pictures during her labor and delivery. I've been reading tips on line and have decided to invest in a primary lens but I'm unsure which would do the job best. I currently have a 18-55 mm lens and a 75-300 mm (Came with the kit). Any professional advice on which primary to get? I've been looking at the 35 mm and 50 mm.