Quote Originally Posted by pentaxuser View Post
Nor presumably will a F6 either? Don't all autofocus cameras rely on contrast and texture to focus otherwise they "hunt" back and forth.

TTL autofocus system the kind used in SLR do need subject with contrast to focus. There are other system that don't need contrast at all like the sonar system used by polaroid and the active IR system used in some small P&S camera. Both of these however can't focus on distance subject.
My post meant to ask the poster who said his F5 won't AF on infinity I am wondering what kind of subject he aim the camera at.