Although I use individual eyepiece focus (IF) binoculars for astronomy on a regular basis, can't say I have much use for IF in my birding binoculars. IF is just not a practical system for close in work on warblers and sparrows and much of my birding is for these groups. That's not to say IF binoculars cannot be used for some types of birding. I once knew a guy who swore by Steiner 7x50 military marine binoculars and, for his birding, they suited him well. He was a duck hunter by fall and a waterfowl birder by spring, operating out of the same blind for both. At waterfowl distances, his IF Steiner was perfect and especially useful for identifying ducks on the wing, since no focusing required.