There are currently no manufacturers, of which I am aware, producing 'true' auto focus binoculars. The majority of camera manufacturers have auto focus lenses as standard on all their compact cameras and most of their SLR range of lenses. You just turn the camera on and point it in the direction you wish to shoot. The lens will usually identify the object you wish to photograph and focus upon it.
There is currently no comparable system available for binoculars.
There have been attempts to emulate auto focus camera lenses with binoculars, the most notable being an instrument produced by Minolta, in the 1990's.
It was reported to be bulky and the performance in terms of accuracy of the item upon which the instrument chose to focus, left something to be desired. To be fair, the same can be said, even today, of camera lenses, in low light conditions and where contrast levels are not distinct.
So what are auto focus binoculars?
The term 'auto focus' is somewhat misleading, as it implies a mechanism to automatically focus the instrument. There is no such mechanism. In fact there are no moving parts involved. The term is used to describe an instrument which has a fixed focus. The focus is set to infinity, and anything in the range of approximately 15m to infinity, will be in focus.
Focus free is another term used to describe such instruments.
These instruments do require the user to have 20:20 vision, as they do rely on the focusing ability of the human eye-ball to achieve part of their objective. Spectacle wearers will have to use these binoculars whilst wearing their glasses.
Auto focus binoculars do have their uses and as opera glasses and for viewing sports in a large stadium, they are a very good option. This is especially so where they may be being shared between two or more people, as the need to re-focus to compensate for each user's eye sight is unnecessary.
For other, more detailed observation requirements, they may not be such an ideal solution. As previously stated, there is some reliance on the focusing ability of the eye. For lengthy periods of observation, this can prove to be tiring especially if there is movement involved.
However, as with all binoculars, auto focus binoculars have their role to play depending on your specific requirements. >