Thread: Swaro SLC W B 8x42 vs Leica Trinovid HD 8x42

Originally Posted by ebf

Tx Sarvo, looking at 8's because as I said mainly NI, I am keen to maximize FOV

8 power with 42 gives greater exit pupil, so by my thinking that is a plus for low-light compared to 10x42

Not sure if that is correct. The human pupil only dilates to 7mm, so if we divide the objective lens size by 7 we get the maximum magnification we should have to optimise the light from the objective. For example a 42 mm objective only matches with 6x mag. So most binos are a compromise and good poor light performance is more likely from better glass. The best binos I have used for poor light were 8 x 56 East German Zeiss. Pitch black could still see deer to 300 metres