Often you will hear the phrase or see in advertising the mention of auto focus binoculars. So what are auto focus binoculars ?
I,m afraid to the best of my knowledge there is no such thing as auto focus. This is a very misleading claim by some manufacturers and sellers. They are in fact fixed focus. In other words they are fixed at around 50-100 yards. Often you will see fixed focus binoculars in the 7×50 range. 7×50 is the most popular fixed focus choice due to their large depth of field. So for example if they are pre-focused at 50 yards, they will show everything in focus from around 30 yards to infinity. They will be OK, but you will not get precise focus throughout the range
To some people , due to restricting disabilities , injury etc a fixed focus set will be ideal, with no focus wheel to turn. But with many sets now coming with less than half a turn of the focus wheel available, there are much better options for most people.
Image upper right shows a pair of focus free 7×50 binoculars. Note there is no focus wheel