The 10x15 Bergheil typically came with a 180mm f4.5 lens. Either a Heliar or a Skopar. I have a 150mm f4.5 Heliar from a 9x12 Bergheil, it's one of my favorite lenses. If you want something that will close up into the camera you need something small and likely vintage in a compur or compound shutter. An 18cm Tessar, Xenar, Heliar, Skopar, or Dagor would do the job nicely.