How do I know? Well, I have a G2 screen for my Nikon F4s. When I focus with the G2 screen (or even with the regular B screen) and can tell by MY eyes that the focus is where it should be, I find my Nikon F4s's green light to be off. That is, when an image is truly in focus, the F4 has the red triangle showing. When I compensate for AF lights and make it in focus according to my F4's AF (that is, get a green light indicator), the image I see from the viewfinder is actually off just a tad. Curious if anyone knows if this is a problem I can somehow fix? And if so, how? I'm tempted to send it to Nikon Canada but I'm not sure if they'll repair my stuff. If anyone has any suggestions, that'd be great!