A recent thread got me to wondering.
With spotting scopes as the magnification goes up, the image gets dimmer. With bino's, if all else is equal, e.g. a 7x50 and a 10x50 of the same brand and model, wouldn't the lower magnification yield a brighter view. And in turn be a more effective low light bin?
And as far as exit pupil. With a standard 5mm "aged" pupil looking into a 7x50 bin with a 7+mm does that allow for more "looking around" within the view or is this something different entirely.
Just curious is all.
Thanks.
During the day, a 7x50 shouldn't be any brighter than a 10x50 because your eyes' pupils close down to maybe 2mm, unable to take "full advantage" of those optics' large exit pupils.
Your second question is answered with the "this is something different entirely," yes. Being able to see more (a wider field of view overall) is dependent mostly upon the eyepiece design.
Howard
loking around is something diff..if the bins are at a 7mm exit pupil but your old eyes can only open to 5mm - you are effectively wasting 2mm of aperture..as for brightness.
if your eyes can open the 7x50 can yield a brighter view in certain circumstances, (but light pollution however negates this). In bright sunlight our puils probably only open to ~3mm anyway - so the actual conditions and amount of light has a lot to do with it.
The 10x may show you more anyway with the extra mag, - a bigger difference may be how steady you can hold 10x as opposed to 7x.
My personal pref is for more mag - the only time i enjoy 7x to 10x is under really dark skies watching the universe float by