>>2997689>with respect to first acquisition and tracking?>I shoot motorsports. Also birds (but only out of interest for gearfagging).Just to make sure we're on the same page, this is the 300mm F4 ED I'm talking about, it's available pretty cheap used and is optically great, just slow. Should be fine with motorsports as long as your technique is good and you don't let the subject leave the focus area causing it to hunt. It's on the short side for birds, especially full frame, and birds are probably the biggest challenge for AF systems to boot. The limiter makes the hunt faster when it happens, but the initial focus is still slow if it has to sweep the range at all. Don't expect it to go from infinity focus to a moving bird at 20' in less than a second, it's just not going to happen unless you're lucky. You'd better be tracking that bird from perch to flight or spec in the distance to up close, because if the camera loses it at all it's going to take too long to focus. The biggest problem IMO is that you can't get it close on a moving subject with MF and let AF take over to track because of the way it switches from MF to AF.
If the AF-S lenses are truly only $300 more than these today, just get the AF-S. This was my first Nikon telephoto prime, and AF-S lenses were nowhere near affordable to me at the time but they are way better. Today I'd just skip it. I rarely use it now because I have a 200-500mm AF-S VR and a 300mm f4 PF VR
