K5d or D300s

Well, it may not help you George but for many, including myself, its a great AF system when used correctly.

It was a serious question. How do they help? How do you use the system correctly?

On cameras I have owned, I have found multiple AF points to be waste of time. But perhaps I wasn't using them correctly.

G

It's a good question. If I was doing a thought experiment, I might imagine that the camera was clever enough to notice the subject tracking across the AF points, as its distance from the camera changes.

Then it could predict where the subject was going to be by the time the shutter opened, and put the focus there, rather than the last point it detected that was in focus.

In that scenario, I could imagine that the more AF points it had, covering more of the frame, the better it might be at the prediction.

So how does predictive AF work?

Chris, you may be right, but I was hoping for something more definitive.

I don't know why, but today's sunshine seems to have brought out a crop of people who specialise in non-answers, like the one at the top here. Quite how he thought he was being helpful, I have no idea. Perhaps he has no idea himself, but just thought he should say something out of politeness.

G

[quote:3496ace15f="K10D]The D300 is good with fast glass for AF. My views are that a D300 is not worth the change in system. A D7000 would be the choice but why change system when a K5 with good glass will out IQ the D7000 out of the box and he already knows Pentax. Running a parallel system as I do is not for everyone and it took a while for me to adapt.

[/quote]Corrected D700 to D7000

Best regards

I can't make a comparative analysis between the K-5 and anything with a Nikon badge, but in response to the original question about the K-5's suitability for motorsport...
[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/Rosberg1.jpg[/IMG]
Korea, with Sigma 150-500mm f5-6.3


[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/White1-1.jpg[/IMG]
Brands Hatch, with Tamron 90mm f2.8 macro (not an obvious choice, perhaps, but using the 100-300mm meant standing in nettles and I was wearing shorts)...


[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/bike19-1.jpg[/IMG]
Mallory Park, with Sigma 100-300mm f4


[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/Trulli4r.jpg[/IMG]
Monza, with Tamron 70-300mm f4-5.6 (focusing manually, because the lens isn't really fast enough to track F1 cars)


[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/PriorAriel2-1.jpg[/IMG]
Cholmondeley, with Sigma 100-300mm f4


[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/JdA2.jpg[/IMG]
Suzuka, with Sigma 150-500mm f5-6.3


[IMG]http://i396.photobucket.com/albums/pp41/simonarron/Simon%20Arron%20-%20club%20motorsport/L1011.jpg[/IMG]
Brands Hatch, with Sigma 100-300mm f4

superb photos sir - nice one