Hello,
look at the Dori distance and the viewing angle. The Sd6CE45 has a great zoom but also a larger initial viewing angle.
Sd49 62.8 -2.6 degrees / Dori = 161 m Identify
SD6CE45 70,3 -1,8 degrees / Dori = 234m Identify
My SD6CE has a slightly better illumination than the SD49 on the near...