I have narrowed my search down to Nikon Monarch ATBs or Audubon Equinox HP, but still am not sure what power to get. These have objectives lens of 42 so exit pupil diameter would be 5.25 for the 8s and 4.2 for the 10s. I can hold the 10 steady but I am worried about low light situations. It seems the 8s would be better. Please give me your thoughts on this. I will be using these for birding, hiking, general use, fishing etc. Thanks.
[QUOTE=elkhorn98]I have narrowed my search down to Nikon Monarch ATBs or Audubon Equinox HP, but still am not sure what power to get. These have objectives lens of 42 so exit pupil diameter would be 5.25 for the 8s and 4.2 for the 10s. I can hold the 10 steady but I am worried about low light situations. It seems the 8s would be better. Please give me your thoughts on this. I will be using these for birding, hiking, general use, fishing etc. Thanks.[/QUOTE]
The 8x have a larger exit pupil so they might be EASIER to use in low light, but on the other hand the 10x will show more DEATIL in any light, especially low light.
You can check this by using what is called twilight factor. It is a quick and dirty way to estimate low light performance. Simply multiply the magnification by the objective diameter and take the square root. Larger objectives AND higher magnification will improve the score, which is a score of rough resolution.
8x42s score 18.33, 10x42s score 20.49
For general use most would lean towards 8x.