As both 10x42 and 8x42 binoculars have 42mm objective lenses and assuming they use the same quality glass and coatings, the light-gathering ability between the two will be the same.How big is the exit pupil on a 10x42 binocular?
10x42 binoculars produce a 4.2mm exit pupil (42/10) When there is plenty of light, your pupils constrict to a size smaller than both the exit pupil on a 10x50 and a 10x42 and thus there is more than enough light for you to perceive a bright view.What advantages does 10x50 offer over 8x42 format?
Question, what advantages does 10x50 offer over 8x42 format? well, the obvious are greater light gathering, finer resolution and smaller detail. 10x50s can see typically 0.4-0.5 magnitude fainter, have 25% larger image scale and resolve equally finer deatil.Are 10x binoculars good for hand-holding?
For the majority of users with relatively steady hands, a 10x binocular is fine for hand-holding and it is only once you go above 12x to 15x that it becomes a problem. However, if you have particularly unsteady/shaky hands, this may be something worth keeping in mind and her an 8x instrument would make a better choice.