The field of focus is very good. Almost without exception if you focus them to you own personal vision anything you need to see will be in focus. There designed for longer range viewing as that's what you need on a boat. I've almost never needed to view something closer than a couple of hundred feet. I think that you will find that the field of focus will be in the range of 100 feet to infinity.

The only time you need to readjust them is when you're looking at the top of the mast. A focusing set of binoculars can be a pain in the ass on a boat.

The only problem I have with them or any other type of binoculars are that when you give them to another person they will change the focus for their eyes. But,,,, even full focus binoculars have one reticle that changes for individual eyes so it really makes no difference.