Ornery, I'm going to modify the above reply. Have been going out post supper and eyeballing deer up in the farm fields to compare the Canon 10x42 IS and a Zeiss HT 10x54. I haven't stayed out any later than "legal light" which here is about 30 minutes past sunset.
The Canon "L" glass is very good and very flat edge to edge without the stabilization feature engaged. Whether or not it resolves detail better than the HT (or other gack that can be measured) would have to be tested by those more technically inclined.
But I can assure you that from 100-850yds with stabilization engaged, the Canon certainly enabled me resolve the physical details of every deer significantly better.
fwiw...
