Be sure to balance that against exit pupil.
Larger exit pupil is better is an internet myth.
January 7, 2012
For my fun and entertainment I laid out some binoculars and two scopes on some sand bags for a low light comparison. After focusing the bins on the deer antlers 131 yards away I decided to see what was the lowest setting I could make out the forks with the scopes. My criteria was would I shoot at the deer which carried them? The exit pupils have been included to show how irrelevant they generally are.
Tasco World Class 4-16X40 @ 7X = 5.71 exit pupil
Bushnell 6500 4 1/2-30X50 @ 5 1/2X = 9.09 " "
After this I turned them up to 8X to match the Bushnell Ultra HD 8X42 and waited.
Binoculars Exit pupil
Minox 15X58 - 3.87mm
REI 10X32 - 3.2
Bush. 8X42 - 5.25
At 5:10 the 8X42 binocs and the scopes set on 8X were out.
Tasco on 8X = 5.00 exit pupil
6500 on 8X = 6.25 � �
I turned up the scopes till I could make out the forks again.
Tasco - 14X = 2.86 exit pupil
6500 - 15X = 3.33 � �
At 5:14 I had to turn up the scopes again.
Tasco - 16X - 2.5 exit pupil
6500 - 20X - 2.5 � �
At 5:15 the REI 10X32 were out.
3.2mm exit pupil
At 5:16 the Tasco and 6500 were out.
Tasco exit pupil: 2.5mm
6500 exit pupil: 2.5mm
Both lasted longer than the 3.2mm of the REI with a 3.2mm exit pupil.
The Minox 15X lasted until 5:20. Exit pupil: 3.87
